FIELD OF THE INVENTION

The present invention relates to a partial replacement of precious platinum catalyst by using non-noble metal such as cobalt and nickel in PEM fuel cell. A stable fuel cell catalyst with low platinum loading was achieved using non-noble functional nano inorganic particles.

BACKGROUND OF THE INVENTION

Fuel cells have attracted great interest as energy conversion devices with high-energy conversion efficiency and low pollutant emission [1]. In this report we have reported the recent development of platinum and non-Pt catalysts and preparation method of catalysts. Precious metal, platinum (Pt), is traditionally used as a high-performance electro-catalyst for proton exchange membrane fuel cells and for fine chemical synthesis, platinum black was the first catalyst used in PEMFCs as the anode and cathode electro-catalyst. The typical particle size was 50 to 100 nm and the physical surface area of Pt black is about 10 m g" . Due to the lower physical surface area, higher Pt loadings (> 4 mg cm"2) were required to achieve useful power densities [2]. Ongoing research is focused on identifying and developing new materials that will reduce the cost and extend the life of fuel cell. Researchers are continued work trying to reduce the precious metal requirement in the fuel cell by designing better materials and improving the overall system of cell [3]. The move from platinum black to carbon supported platinum catalysts has significantly cut platinum requirements [4]. The present invention relates to a platinum supported catalyst for the anode of a PEM fuel cell with high resistance to poisoning by carbon monoxide. The catalyst contains the noble metals platinum and ruthenium on a finely divided, conductive support material. It is particularly suitable for use as an anode catalyst in fuel cells with a polymer electrolyte membrane [5]. Pt and Pt-alloy electrocatalysts supported on carbon are currently used in cathodes and anodes of PEMFCs [6]. Major challenges are to the replacement of high cost of precious platinum catalyst by non-noble metal. Thus, considerable efforts have been devoted to the development of new alternative support materials to improve the stability of catalysts. Therefore author innovate the new technique to the partial replacement of platinum catalyst by using the two-step chemical reduction method. Carbon supported platinum metal alloy catalysts (Pt-M/C) are widely used in low temperature fuel cells. In present, we focus on synthesis of carbon supported Pt-Ni and Pt-Co catalysts (Pt-Ni/C & Pt-Co/C) by using ultrasonic irradiation method is described in order to apply practically to fuel cell. Ultra-probe sonicator irradiation method is novel process and it is confirmed to be one of the high potential methods to synthesize carbon-supported Pt-Ni & Pt-Co catalysts. It operates at a frequency range 20 kHz to several KHz and ultrasonic power 110-120 watts. Their potentiality as ORR catalysts in proton exchange membrane fuel cell is proved by evaluating the electro-catalytic activity of the prepared Pd-Ni/C & Pt-Co/C catalyst.

Proton Exchange Membrane Fuel Cells (PEMFCs) and role of Platinum Catalyst

The proton exchange membrane fuel cell (PEMFC), also called polymer electrolyte fuel cell (PEFC) or the solid polymer fuel cell (SPFC) because the electrolyte of PEMFC is the solid polymer. The mobile ion in the polymers used is an H+ ion, so the basic operation of the cell is essentially the same as for the acid electrolyte fuel cell.

Reduction & Oxidation on Pt:

The issues of low activity and dispersion of Pt catalysts on the supports can lead a significant decrease in the whole performance in low catalytic activity. At present, Pt or Pd based catalysts exhibit the good catalytic and chemical properties of HOR and ORR in PEMFCs and DMFCs. So far, the Pt catalyst has showed the highest activity to ORR, and most of research has led to understand ORR on the whole catalytic systems of Pt or Pt based alloy bimetal, ternary, multi-metal catalysts using a low Pt loading at minimal level. The urgent demands for the low Pt catalyst loading weight, total high-performance, durability and effective-cost design are very important [7]. Smaller particle sizes are more desirable for PEMFC electrodes because smaller the particles, the greater the particle surface area to reduce hydrogen [8].

Hydrogen Oxidation Reaction (HOR)

At anode side occurs the mechanism of hydrogen electrooxidation on Pt in acid electrolytes is thought to proceed by rate-determining dissociative electrosorption of molecular hydrogen (Reaction 1) followed by facile electron transfer (Reaction 1-7) [9-14]

Oxygen Reduction Reaction (ORR)

At cathode side the oxygen reduction reaction occur in two main pathways in acidic electrolytes as follows:

At present, the phenomena of ORR kinetics and mechanisms occurring on the Pt catalysts were studied in a very high overpotential loss observed [10-13]. Thus, the very high loadings of Pt must be supplied in the high requirements of the FCs operation. However, studies reveal that the addition of precious or transition metals to Pt can change the electronic structure of Pt and enhance the ORR catalytic performance [14, 15]. The improvement in catalytic activity when Pt is alloyed with transition metals is attributed to the increased Pt d-band vacancy and Pt-Pt interatomic distance [16].

Difficulties in Replacement of Platinum:

The following sections will discuss the performance of pure Pt compared to other pure metals with respect to these characteristics.

Activity: It able to adsorb the reactant strongly enough to facilitate a reaction but not so strongly that the catalyst becomes blocked by the reactant or products. Pt has the highest activity of all bulk metals. The HOR is extremely quick and already requires much lower Pt loadings than the ORR. That said, Pt is.currently used for the anode catalyst for the HOR and hence is a target for fuel cell cost reduction [17-18].,

Selectivity: to make the desired product and minimize the production of undesirable intermediates and side products. The catalyst must progress the reaction to make the desired product whilst minimizing the production of undesirable intermediates and side products. [19]. Stability: to withstand the operating environment in a fuel cell, including strong oxidants, , reactive radicals, an acidic environment and high and rapidly fluctuating temperatures, all whilst under an applied voltage. Lack of short term stability is most immediately obvious as a loss in kinetic activity, but long term stability of the catalyst is key to overall system durability [20, 24].

Poisoning Resistance: to be resistant to poisoning by impurities likely to be found in the fuel cell itself and in the feed gases. A good catalyst must be resistant to poisoning by impurities likely to be found in the fuel cell itself and in the feed gases. Impurities in both the hydrogen and the air streams may have a negative impact upon the workings of a PEMFC [21-22]. Alternatives to Pure Platinum: While Pt is the best pure metal in terms of activity, selectivity and stability for both anode and cathode in a PEMFC. The perfect catalyst according to the Sabatier principle would have slightly different electronic properties. Therefore a lot of research focuses on fine tuning the electronic properties of Pt in order to optimize the resulting catalyst material [10-21]. Approaches currently used to improve Pt activity are:

a. Alloying with one or more other metals;

b. Layering Pt on or just below the surface of another metal;

c. A core-shell approach where a core of cheaper metal is coated with Pt;

d. Alloying Pt followed by dealloying such that the finished Pt lattice structure retains some of the original structural strain associated with alloying.

Alloying: Pt-based binary alloys (Pt-X) have shown enhanced activity towards the ORR. In the last few years results have shown that many alloys with the general formula Pt3X (where X is a 3d transition metal) give high activity. Whilst these Pt3X alloys have proven to be highly active towards the ORR, stability as well as activity is crucial for any viable PEMFC catalyst. Hence it must be ascertained whether or not base metal leaches from these systems. Both theoretical predictions and experimental observations indicate that strong leaching takes place. State of Art of Existing Method for the carbon supported catalyst:

The various inventors have already worked on carbon supported catalyst used in fuel cell applications, the details of state of art are reported as follows.

U.S. Pat. No. 7867648 B2, U.S. Pat. No. 20090226796 Al, discloses of which is prepared supported catalyst comprising nanostructured elements which comprised microstructured support whiskers bearing nanoscopic catalyst particles made according to the present method. The present disclosure also provides a fuel cell membrane electrode assembly comprising the present supported catalyst. In this vacuum deposition of material comprising at least one transition metal is cobalt or iron.

U.S. Pat. No. 5593934 discusses the synthesis of carbon supported platinum alloy such as platinum, manganese and iron catalyst. Also includes comparative examples demonstrating carbon-supported catalysts comprising all are in atomic weight percent 50% Pt, 25% Ni and 25% Co; 50% Pt and 50 % Mn; and Pt alone.

U.S. Pat. No. 20080161183 Al, the discloses of invented that improved stability of Pt-Co/C in accordance with certain embodiments of the present disclosure is due to the following: (i) the excess Co in the alloy has been removed by leaching the catalyst in H2SO4 solution (only stable Co species remain in the carbon composite support); (ii) surface functional groups such as oxygen and nitrogen introduced during the preparation of the carbon composite support inhibit Co migration and dissolution; and (iii) interaction of Pt with Co/C at high temperature results in formation of a chemically and structurally stable Pt-Co/C alloy when compared with the
conventional synthesis routes involving Co deposition on Pt/C.

U.S. Pat. No. 5079107, discloses an electrocatalyst for a phosphoric acid electrolyte fuel cell at the cathode side comprising a ternary alloy of Pt-Ni-Co, Pt-Cr-C or Pt-Cr-Ce. U.S. Pat. No. 7351444 B2, invented that new series of catalytically active thin-film metal alloys with low platinum concentration supported on nanostructured materials. In certain embodiments, a ternary catalysts of Ni-Co, Ni-Mo, Ni-V, Co-Mo, Co-V and Mo-V at fixed 40% Pt or 20%> Pt in each alloy system on cathode side.

U.S. Pat. No. 4985386 discloses the catalyst comprising carbon supported and carbides of Pt, carbides of a second metal selected from Ni, Co, Cr and Fe, and optionally, if necessary of Mn on carbon supports. The reference also discloses a method of making a carbon supported catalyst by reductive deposition of metal ions onto carbon supports followed by alloying and at least partial carburizing of the metals by the application of heat and high temperature treatment with carbon monoxide, carbon dioxide or lower hydrocarbons.

U.S. Pat. No. 7811965, discloses the use as a catalyst in oxidation or reduction reactions comprising platinum, copper, and nickel, wherein the concentration of platinum therein is greater than 50 atomic percent and less than 80 atomic percent, and further wherein the sum of the concentrations of platinum, copper and nickel is greater than 95 atomic percent.

U.S. Pat. No. 5096866, E.P. Pat. No. 0355853 A2, discloses supported platinum alloy electrocatalyst for an acid electrolyte fuel cell, said electrocatalyst consisting better activity of an electrically conductive powdery carbon carrier and dispersed in and deposited on the carrier, an ordered platinum-iron-copper ternary alloy comprising 40 to 60 % atomic of platinum, 13 to 40 % atomic of iron and 13 to 40 atomic percent of copper. An electrode for an acid electrolyte fuel cell having an excellent output performance and a long operating life is also provided which comprises the above supported platinum alloy electrocatalyst and a water-repellent binder which are bonded to an electrically conductive and acid-resistant supporting member. U.S. Pat. No. 5178971 A, found that supported platinum quaternary alloy electrocatalyst used in the preferable composition range on the atomic percentage of the platinum-cobalt-nickel-copper quaternary solid solution alloy is 40-70 % for platinum, 9-27 % for cobalt, 9-27 % for nickel and 9-27 % for copper in acid electrolyte fuel cell. A platinum alloy electrocatalyst comprising an electrically conductive carrier, a water-repellent binder and an electrically conductive and acid-resistant supporting member to which the electrocatalyst and the binder are bonded. U.S. Pat. No. 006007934A, the discloses platinum supported catalyst for the anode of a PEM fuel cell with high resistance to poisoning by carbon monoxide, containing the noble metals platinum and ruthenium on a finely divided, conductive support material. It is a feature of the invention that in the catalyst of the invention, the two noble metals are not alloyed with each other. Rather, they are present in a highly dispersed form on the support material, wherein the crystallite size of the platinum is less than 2 nm and that of the ruthenium is less than 1 nm. Mathiyarasu and Phani et. al. [23], reported that the carbon-supported nanoparticles of Pd-Co-M, (M = Pt, Au, and Ag) catalysts for direct methanol fuel cells DMFCs in a ratio of 70:20:10 were prepared through reverse micro-emulsion method. TEM & XRD confirmed that the avg. particle size found to be approximately 20 nm for the prepared materials, in that Pd-Co-Pt alone showed a high methanol tolerance and ORR activity than other combination materials with Au and Ag. Antolini et. al. [24], examine that carbon supported high & low stability binary platinum metal alloy catalysts Pt-Co prepared. Also used as an alloyed Pt-M catalysts as cathode materials in low temperature fuel cells. In addition to a higher activity for oxygen reduction and a higher methanol tolerance, these catalysts present a higher stability against dissolution than the state-of-the-art pure platinum cathodes.

Santiago et. al. [25], prepared cathode material Pt7oCo3o/C nanocatalysts made by polyol method with a long-chain diol as reducing agent have small particle size 1.9 ± 0.2 nm & narrow size distribution, homogeneously dispersed on carbon support. They also showed that prepared catalyst presents an excellent performance as PEMFC cathode material without the need of any further heat treatment.

Deivaraj et. al. [26],examined that the electro-oxidation of methanol for carbon supported bimetallic Pt-Ni nanoparticles were prepared by the reduction of K^PtCU and NiCl2.6H20 by hydrazine using PVP as a stabilizer under different conditions, namely by conventional heating (PtNi-1), by prolonged reaction at room temperature (PtNi-2) and by microwave assisted reduction (PtNi-3).

Markovic et. al. [27], examined the various the underpotential deposition method, the classical metallurgical method and deposition of pseudomorphic metal films for single crystal surfaces of bimetallic Pt-Ni and Pt-Co catalysts made. It was used as electro-catalysis of the ORR on model bimetallic surfaces on Pt-Ni and Pt-Co bulk alloys for to resolve the enhanced ORR kinetics on supported Pt-Ni and Pt-Co catalysts.

Paulus et. al. [28-29], investigated that the comparative study of the ORR on two carbon-supported Pt-based alloy catalysts like Pt-Ni and Pt-Co in aqueous acidic electrolyte at low temperature. Carbon supported alloy catalysts using the thin film rotating ring disk electrode (RRDE) method in 0.1 M HCIO4 in the temperature range between room temperature and 60°C. Pt-Co in the atomic ratio 3:1, 1:1 and Pt-Ni in the ratio 3:1 were stable during the experiments. Both have the bulk compositions of 50 and 75 at. % Pt, with the alloying elements being Ni and Co. Comparison is made to a pure Pt catalyst on the same carbon support, Vulcan XC-72, having the same metal loading of 20 wt % and nominally the same particle size of 4 ± 2 nm. Yu et. al. [30], invented that to check the durability of the synthesized Pt-transition metal alloys such as Pt-Co/C cathode catalyst improved in PEM fuel cell. It also shows to evaluate the durability of a Pt-Co cathode catalyst in the Pt to Co atomic ratio 2.5:1 in a. dynamic fuel cell environment with continuous water fluxing on the cathode.

The present invention therefore describes a process for synthesis of stable, colloidal dispersions of carbon supported low loading of Platinum with non-platinum metal nanoparticles (Pt-X/C, X= Ni, Co). From literature review seen that Pt has been widely used as a catalyst in PEM fuel cell applications. However, besides high overpotential, the Pt catalyst has occurs some drawbacks such as expensive cost, decrease in catalytic activity by CO poisoning and short catalytic stability [31-33]. Searching the proper alternative being able to partially replace the Platinum catalyst was efforts is (i) to curtail the overpotential, (ii) to minimize the consumption of expensive Pt, (iii) to increase the ORR activity and (iv) to improve the catalytic stability, many efforts have been made to date [31-35].

OBJECTIVES OF THE INVENTION

To increase an activity and stability of Pt-Co and Pt-Ni carbon supported catalyst for PEM fuel cell applications. Carbon supported catalyst like use of Pt-X/C alloy catalysts (X = Co, Ni), shown as a twofold activity first is allowing a reduction in platinum loading and second is enhancement of activity for oxygen reduction.

SUMMARY OF THE INVENTION

A series of Pt-X/C catalysts were prepared by hydrazine reduction of K2PtCl6 and cobalt (II) nitrate hexahydrates (Co (N03)2.6H20) and also Nickel (II) chloride hexahydrates (NiCl2.6H20) in water. Features and advantages of the invention will become apparent in the following detailed description and the preferred embodiments with reference to the accompanying drawing. The main objective of the invention is to optimize the Carbon supported catalyst like use of Pt-X/C alloy catalysts (X = Co, Ni) and to synthesize Pt-Co/C and Pt-Ni/C using the same. One of the objectives of an invention is to increase an activity and stability of Pt- Co and Pt-Ni carbon supported catalyst for PEM fuel cell applications. Another objective of the invention is to shown as a twofold activity first is allowing a reduction in platinum loading and second is enhancement of activity for oxygen reduction.

Carbon supported atomic weight 70% Pt & 30% Ni nanocatalyst (Pt7o-Ni3o/C): Use platinum precursor in the range of 0.001 to 0.003 M Potassium hexachloroplatinate (IV) with using stabilizing or surfactant such as polyvinyl pyrrolidone (PVP) & 0.002 M of nickel chloride with PVP add in 1.5 g of Vxc72 carbon powder during magnetic stirring 30 min. Use ultra-sonic probe sonicator (20 mm size of diameter, frequency range 20 KHz & ultrasonic power 110-120 watts) and, added drop by drop 0.01 M of 20 mL Hydrazine hydrate solution prepared in water with PVP in that mixture solution of for 30 min. The final product solution is magnetic stirring for 30 min. Centrifuge the final product solution for removal of impurities and wash with hot distilled water and dry it at 80 °C.

Synthesis of Pt-X/C, (X = CO, Ni) nanoparticles is in ultra-sonic probe sonicator (20 mm size of diameter) by using Hydrazine as a reducing agent as follows: Carbon supported Pt-Co & Pt -Ni nanocatalyst (Pt-Co/C & Pt-Ni/C):

Use platinum precursor 0.01 M of 20 mL potassium hexachloroplatinate (IV) (K^PtCle) with . PVP and 0.005 M of 20 mL cobalt (II) nitrate hexahydrates or nickel (II) chloride hexahydrates with PVP add in 1.5 g of Vxc72 carbon powder during magnetic stirring 30 min. After that, add reducing agent drop by drop 0.04 M of 20 mL Hydrazine hydrate prepared in water with PVP in that mixture solution for 30 min.

DETAILED DESCRIPTION OF THE INVENTION

Carbon-supported Pt-X electro-catalysts (X=Co, Ni): (To synthesis of stable, colloidal dispersions of carbon supported, A) Pt-Co nanoparticles that is Pt-Co/C, B) Pt-Ni nanoparticles that is Pt-Ni/C. In the preparation of MEA, catalyst slurry ink prepared by incorporate the platinum precursor and cobalt or nickel precursor in carbon powder using hydrazine as a reducing agent is added by drop by drop in ultra-probe sonicator having 20 mm diameter size and frequency range 20 KHz, ultrasonic power 110-120 watts. After synthesized of carbon supported Pt-Ni or Pt-Co nanoparticles, the impurities were removed by using centrifuge and washed the materials with distilled water 2-3 times and heat it at 80 to 90 C. Preparation of gas diffusion layer (GDL) inks following the final step, take 2.5 gm of Vxc72 carbon black and add demineralised water to wet the carbon powder and sonicate it for 10 to 15 min till you get uniform dispersion using bath sonicator. Then add 1:1 v/v water/isopropanol and sonicate for 15 to 30 minutes to make uniform dispersion of carbon powder (like ink). The precipitate was re-dispersed under sonication in 1:1 v/v water/isopropanol. Add 10 % Teflon solution of as per respective quantity of the carbon powder taken. Then again sonicate it and make the solution like ink.

Membrane Electrode Assembly (MEA) preparation for testing of Pt-X/C (X=Co, Ni) nanocatalyst:

In the preparation of MEA, take 0.1 g of prepared Pt-X/C catalyst, wet with demineralised water and also add 1 mL of IP A and sonicate for 30 min. Now add 5 % of Nafion solution (0.84 mL) for binding of catalyst as per ratio of Nafion to carbon (N/C) taken as per respective amount of catalyst and again sonicate for 30 min. A paste like ink solution formed, this is catalyst ink. Coat the catalyst ink over the GDL on both anode and cathode by using nylon brush. After coating, dry it at 50 C. Repeat the same procedure until catalyst loading at anode and cathode reaches near to 0.25 mg/cm and 0:5 mg/cm respectively. This process of catalyst coating on GDL is called gas diffusion electrode (GDE). Now sinter the GDE at 70°C for an hour. GDE's are hot pressed with NR-212 Nafion membrane at a pressure 60 kg/cm , temperature 90 C and time 3 min. MEA consist of GDE on both sides, Nafion membrane in middle and placed in single cell.

DETAILED DESCRIPTION OF THE DRAWINGS

Present discuss is generally directed towards a novel carbon-based catalyst used for both sides of fuel cell and the processes for making the same.

Figure 1: Illustrates that detailed schematic view of single PEM fuel cell are as follows: 1&6) Flow channels for both anode side and cathode side respectively, 2&7) Gas diffusion layers (GDL) both side, 3) Proton exchange membrane, 4) Anode side catalyst coat material, 5) Cathode side catalyst coat material. In figure 1, 1 & 6 are the flow channels which are generally used for flow the reactant gases i.e. fuel (H2) and oxidant (O2) or air. It is also called bipolar plate, which is made of graphite or carbon-carbon composite material. It distributes the reactant gases uniformly over the active area and also supports the membrane electrode assembly (MEA) robustly. Bipolar plates occurs different flow geometry such as parallel, serpentine and Interdigitated. 2 & 7 are the gas diffusion layers (GDL's). Gas diffusion layers (GDL's) facilitate gas transport from the anode to the cathode side and vice versa and also conducts electrical current. It is porous and electrically conductive and is typically composed of carbon fibers substrate of carbon paper or carbon cloth. The GDL may also be called a fluid transport layer (FTL) or a diffuser/current collector (DCC). 3 is the PEM, is a durable, non-porous, electrically non-conductive mechanical barrier between the reactant gases, yet it also passes H+ ions readily. 4 & 5 are the Gas diffusion electrode (GDE's). In some embodiments, the anode and cathode electrode layers are applied by catalyst and the catalyst coated GDL's are called Gas diffusion electrode (GDE). The resulting catalyst-coated GDL's i.e. GDE sandwiched with a proton exchange membrane (PEM) to form a five layer MEA. The five layers are anode GDL, anode electrode layer, PEM, cathode electrode layer and cathode GDL. In other embodiments, the anode and cathode electrode layers are applied to either side of the PEM, and the resulting catalyst-coated membrane (CCM) is sandwiched between two GDL's to form a five-layer MEA. Figure 2: Illustrates an experimental set up for the preparation of carbon supported catalyst using ultra-probe sonicator having 20 mm diameter size and frequency range 20 KHz, ultrasonic power 110-120 watts, 1) ultrasound generator box, 2) probe sonicator, 3) process beaker for carbon supported Pt precursor & Ni or Co precursor, 4) Pipette for reducing agent (hydrazine), 5) head of sonicator for generate the ultrasound, 6) jacket for cold water. Experimental procedure for synthesis of carbon supported Pt-Co or Pt-Ni nanoparticles is carried in probe sonicator by irradiation method. The preparation of catalyst is explained in examples 1, 2 & 3. It is tested with single cell in fuel cell test station.

Figure 3, 6, 8 & 10: Illustrates that the cyclic voltammetry used to determine the potential dependence for catalyst reduction and oxidation as well as fuel oxidation or reduction. Protons interact with the catalyst surface in the hydrogen region. They adsorb in the negative going scan and desorb in the positive going scan. The CV can also be used to determine the electrochemical surface area. The cyclic voltammetry can be.used to calculate the CO coverage by integrating the areas under the hydrogen desorption and CO oxidation peaks. It is widely accepted that both Pt and Ni or Co can be characterized in this manner, where the surface area from the hydrogen peaks is determined from the relationship of 210 \xC cm" and from the CO peaks by the relationship of 420 (iC cm" . Cyclic voltammetry is performed in 0.1 M H2SO4 (GFS, double distilled) order to clean the surface. The potentiality is scanned from 0.02 to 1.2 V vs RHE at a scan rate of 50mV/s.

Figure 4, 7, 9 & 11: Illustrates that the linear sweep voltammetry (LSV) for all prepared electrocatlyst materials. LSV used for the oxygen reduction reaction (ORR) study, LSV studied . on the rotating disc electrode (RDE) for the electrocatalysts using a scan rate of 5 mVs"1 in an oxygen saturated 0.5 M H2SO4 & other acid. It also used for calculate the constant open circuit potential (OCP) without any load applied on fuel cell system. From figure 4, Pt70-Ni3o/C (70% Pt 6 30% Ni) nanoparticles, OCP is 0.81V for 1 cm2 active area of GDE, similarly for others figure 7 for Pt-Co/C nanoparticles, MEA having 25 cm active area for both anode and cathode of GDE gives OCP 0.926V, figure 9 for Pt-Ni/C nanoparticles, MEA having 25 cm active area for both anode and cathode of GDE shows OCP 0.964 V. From figure 11 on comparison study between Pt-Co/C & Pt-Ni/C nanoparticles for both anode and cathode, the higher OCP for Pt-Ni/C electrocatalyst than Pt-Co/C electrocatalyst i. e. OCP 0.964 V.

The fuel cell is assembled for testing consists of the following components: membrane, catalyst layers, reference electrode, gas diffusion layers, gas/liquid flow fields, current collector plates, gaskets and others some things nuts, bolts. Each component will be discussed in order of assembly. Fuel cell operated by stepping down the voltage from its open circuit value to its short circuit value; one would obtain a V-I (or polarization) curve. Such a curve is illustrated in figure 5,12 & 13 and also result reported in Table 1.

Figure 5: Illustrates that the polarization curve and power density curve of Pt7o-Ni3o/C (70% Pt & 30% Ni) nanoparticle for a 25 cm active area of single PEM fuel cell. The experiments were performed under following conditions: i) cell temperature = 55 °C, ii) anode catalyst loading = 0.25 mg/cm , iii) cathode catalyst loading = 0.50 mg/cm , iv) H2 humidification temp: set temp = 65 °C & line heater temp= 70 °C, v) O2 humidification temp: set temp = 60 °C & line heater temp = 65 °C, vi) hydrogen gas line pressure = 1.9 bar and vii) oxygen gas line pressure = 3.1 bar; Figure 12: Illustrates that the polarization curve and power density curve of Pt-Co/C nanoparticle for a 25 cm active area single PEM fuel cell. Figure 13: Illustrates that the polarization curve and power density curve of Pt-Ni/C nanoparticle for a 25 cm active area of single PEM fuel cell. The experiments were performed under following same conditions for both Pt-Co/C & Pt-Ni/C prepared GDE: i) cell temperature = 65 °C, ii) anode catalyst loading = 0.25 mg/cm , iii) cathode catalyst loading = 0.50 mg/cm , iv) H2 humidification temp: set temp = 72 °C & line heater temp= 77 °C, v) 02 humidification temp: set temp= 70 °C & line heater temp = 75 °C, vi) Hydrogen gas line pressure = 1.9 bar and vii) Oxygen gas line pressure = 3.1 bar; Table 1: Structural composition of the Pt-M/C electrocatalysts, (M = Co & Ni etc.) shows the polarization curves results as follows: X-ray diffraction (XRD) is widely used for determining the atomic and molecular structure of crystalline material. In this research powder XRD measurements were carried out using (PANalytical Model of XPERT-PRO powder system) a diffractometer with Cu Ka source (X=\.540598 or 1.5418 A0) in the 20 scan range between 06 and 80° at a rate of 40 sec. per step or 0.625° mm"1. The sample investigated by X'PERT Pro powder system using Cu K-alpha radiation at a generator voltage of 45 kV and a tube current of 30 mA. Apart from the investigation of the crystal structure and the identification of different metal phases, the diffraction patterns obtained from XRD can also be used to estimate the size of nanoparticles or crystallites. The broadening of a peak in a diffraction pattern is found to be related to the size of the nanoparticles by using a Scherrer equation; where /?(20) is the full width at half maximum intensity (FWHM in radians), K is the dimensionless shape factor or known as the Scherrer constant that is 0.89, X is the X-ray wavelength (A=l.540598 A°), d is the mean or avg. size of the crystallites and 6 is the Bragg angle.

Figure 14, 15, and 16: Illustrates that the XRD pattern of carbon supported 70% Pt- 30% Ni nanoparticle (Pt7o-Ni3o/C), Pt-Co (Pt-Co/C) and Pt-Ni (Pt-Ni/C) respectively. According to JCPDS card 04-0784, these peaks can be assigned to Pt (111), (200) and (220), respectively. The 26 values of 39.75, 46.24, 67.44, 81.28 (for Pt, JCPDS 04-0802) and 40.11, 46.65, 68.11, 82.09 (for Co, JCPDS 15-0806) correspond to (111), (200), (220) and (311) crystal planes for each pure metal, respectively. The XRD pattern of ultrasonically prepared electrocatlyst Pt70-Ni3o/C as shown in figure 14. It was observed peaks around at 20 = 13.81°, 16.69°, 31.69 , 40.065 , 46.51°, 68.14°, 81.69° and 85.55°, which are characteristics of face centered cubic (fee) Pt & Ni phase, except that the first two broad peak values of 13.81 °& 16.69° were associate with the Vulcan XC-72 carbon support.

Figure 15, illustrated that the fee Pt and fee Co phase, the diffraction peak of Pt in Pt-Co/C electrocatalyst were shifted to higher values of 20 = 24.89°, 39.88°, 46.40°, 67.32° and 72.62°, which are characteristics of face centered cubic (fee) Pt & Co phase, except that the first broad peak values of 24.89° was associate with the Vulcan XC-72 carbon support. Figure 16 illustrated that the fee Pt and fee Ni have distinctive diffractions shifted to higher values and the values of 20 = 24.59°, 39.99°, 46.05°, 67.99°, 72.70°, 81.39° and 88.14°. Deivaraj et. al. [26] shows that the XRD of nickel are characterized by peaks at 20 = 44.5 (111), 51.8 (200) and 72.70° (222), while that of fee Pt by peaks at 20 = 39.9 (111), 46.2 (200), 67.99 (220), 81.0 (311) and 86.1 (222). It was clearly seen that Ni/C sample represented the typical Ni fee crystal structure, except that the first broad peak at 20 =26° was associated with the Vulcan XC-72 carbon support. Figure 17 illustrated that the XRD results of comparison between Pt-Co/C & Pt-Ni/C. It was also obvious that the XRD pattern of Pt7o-Ni30/C, Pt-Co/C, and Pt-Ni/C catalyst combined the crystal features of Ni or Co and Pt coexistence of both of them. According to Scherrer's formula, the obtained average mean particle crystal sizes at broad peak of Pt (111) plane of Pt70-Ni3o/C, Pt-Co/C, and Pt-Ni/C were tabulated in Table 2.

Figure 18, 19 & 20: a & b illustrated that transmission of electron microscope (TEM) images of carbon supported 70% Pt- 30% Ni nanoparticle (Pt7o-Ni3o/C)? Pt-Co (Pt-Co/C) and Pt-Ni (Pt-Ni/C) respectively. TEM images of the three samples shows small differences in Figures 18-20 and Table 2. In Figure 18, Pt7o-Ni3o/C prepared by carbon supported on weight basis of 70% Pt-30%» Ni nanocatalyst (Pt7o-Ni3o/C) showed a high degree of agglomeration and very broad particle size distribution (4-6 nm), Figure 19, Pt-Co/C prepared at room temperature carbon supported 0.01 M K2PtCl6 with PVP and 0.005M of cobalt (II) nitrate hexahydrates with PVP, consisted of nanoparticles in the range of 4-8 nm. Similarly Figure 20, Pt-Ni/C prepared by carbon supported 0.01 M K2PtCl6 with PVP and 0.005M of Nickel (II) chloride hexahydrates with PVP, showed well dispersed nanoparticles of size ranging from 2-6 nm. Table 2: Structural characteristics of the Pt-M/C electrocatalysts, M = Co & Ni etc.

DETAILED DESCRIPTION WITH RESPECT TO EXAMPLES

The electrically conductive Vulcan XC-72R carbon powder (products of Cabot Corporation), Potassium (IV) Hexachloroplatinate (K^PtC^) procured from Sainergy Fuel Cell Pvt. Ltd., Chennai, Nickel Chloride (II) Hexahydrates, Cobalt (II) Nitrate Hexahydrates were procured from Merk Specialities Pvt. Ltd., Mumbai, 99% pure Hydrazine Hydrate was procured from Sd Fine chemicals Ltd., Mumbai.

The following examples and comparative study illustrates the present invention more specifically.

EXAMPLE 1: Carbon supported atomic weight 70% Pt & 30% Ni nanocatalyst (Pt?o-Ni3o/C) according to the invention: Use platinum precursor 0.0024 M Potassium (IV) Hexachloroplatinate (K2PtCl6) (0.0233 g of K2PtCl6 in 20 mL water) with stabilizing or surfactant such as polyvinyl pyrrolidone (PVP) & 0.002M of Nickel Chloride (II) Hexahydrates (0.00951 g of NiCl2.6H20 in 20 mL water) with PVP and add 1.5 g of Vxc72 carbon powder during 30 min magnetic stirring. After that using irradiation method by ultraprobe sonicator, add drop by drop 0.01 M Hydrazine hydrate (0.01944 mL in 20 mL of water) with PVP and mix the solution for 30 min.

EXAMPLE 2: Carbon supported Pt-Co nanocatalyst according to the invention: Use platinum precursor 0.01 M Potassium (IV) Hexachloroplatinate (K2PtCl6) (0.0971 g of K2PtCl6 of 20 mL water) with PVP and 0.005 M of.Cobalt (II) Nitrate Hexahydrates (0.029104 g in 20 mL water) with PVP and add 1.5 g of Vxc72 carbon powder during 30 min magnetic stirring. After that using irradiation method by ultraprobe sonicator, add drop by drop 0.04 M Hydrazine Hydrate (0.0388 mL in 20 mL of water) with PVP and mix the solution for 30 min.

EXAMPLE 3: Carbon supported Pt-Ni nanocatalyst according to the invention: Experimental procedures are same as example 2 but in place of cobalt precursor using nickel precursor. Use platinum precursor 0.01 M Potassium (IV) Hexachloroplatinate (K^PtCle) (0.0971 g of K2PtCl6 of 20 mL water) with PVP and 0.005 M of Nickel (II) Chloride Hexahydrates (0.023771 g in 20 mL water) with PVP add 1.5 g of Vxc72 carbon powder during 30 min magnetic stirring. After that using irradiation method by ultraprobe sonicator (frequency range 20 KHz, ultrasonic power 110-120 watts), add drop by drop 0.04 M Hydrazine Hydrate (0.0388 mL in 20 mL of water) with PVP and mix the solution for 30 min.

EXAMPLE 4: Supported Pt-Co/C and Pt-Ni/C catalyst comparative study of example 2 & example 3 according to the invention: Comparative graphical study of synthesized carbon supported electrocatalysts Pt-Co/C and Pt-Ni/C experimental details explained in above examples 2 & 3. Therefore, Pt-Co/C and Pt-Ni/C catalyst were successfully synthesized by ultrasonic irradiation. This indicates that the ultrasonic irradiation method can be one of the high potential methods to synthesize carbon-supported Pt-Co and Pt-Ni catalysts.

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5. CLAIMS:

We are claim as:

1. A low platinum loaded with non-platinum metal catalyst for the both anode and cathode of a PEM fuel cell with high resistance to poisoning by carbon monoxide, comprising the noble metals platinum and non-noble metal such as cobalt and nickel deposited on a finely divided, conductive support material, said noble metals being not alloyed with each other and being present in highly dispersed form on the carbon support material.

2. The supported catalyst according to claim 1, wherein example 1 the weight ratio of platinum to nickel is 70% and 30%.

3. The supported catalyst according to claim 1, wherein example 2 & 3, the molar ratio of Platinum to cobalt and platinum to nickel are 1:0.5.

4. A process for preparing a supported catalyst according to claim 1, comprising' adding the precursors solution of platinum, cobalt or nickel suspending an electrically conductive support material carbon in water to form a colloidal suspension solution.

5. The supported catalyst according to claim 4, wherein using as a strong reducing agent like hydrazine in the suspension solution of carbon supported precursors carried out in Ultra-probe sonicator (frequency range 20 KHz, ultrasonic power 110-120 watts) irradiation process.

6. Process according to claim 5, wherein carried out all solution mixed at a room temperature.

7. Here according to clam 1, coat the prepared catalyst carbon loaded Pt-Ni or Pt-Co catalyst to both side of anode and cathode reaches to 0.25 mg/cm and 0.5 mg/cm respectively.

8. A membrane electrode assembly for PEM fuel cell system which consist of Nafion membrane, and has gas diffusion electrode applied to both the cathode and anode sides, wherein there is present a catalyst layer on both side which is carbon supported catalyst Pt-Co or Pt-Ni according to claiml, example 1 to 3. Test this all materials of MEA in 25 cm single PEM fuel cell.