Abstract:
Methods for the rapid synthesis of catalyst are provided, as well as catalyst formed from such methods. One method of the rapid synthesis of catalyst comprises forming a homogenous solution comprising a precious metal precursor and a catalyst substrate, reducing the precious metal precursor to precious metal nanoparticles, and depositing the precious metal nanoparticles onto the catalyst substrate to form catalyst particles. The reducing and depositing steps comprise controlling a rate of increase in temperature of the solution with microwave irradiation until the solution is a predetermined temperature and maintaining the solution at the predetermined temperature with microwave irradiation. The method further comprises detecting completion of the reduction and deposition and ceasing microwave irradiation upon detection.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 13/537,842 filed on Jun. 29, 2012 and incorporated herein in its entirety. 
    
    
     TECHNICAL FIELD 
     The disclosure relates in general to the synthesis of fuel cell catalyst, and in particular to the synthesis of fuel cell catalyst using controlled microwave heating. 
     BACKGROUND 
     Fuel cells efficiently and electrochemically convert fuel into electric current, which may then be used to power electric circuits, such as drive systems for vehicles. A fuel cell containing a proton exchange membrane is an electrochemical device that converts chemical energy to electrical energy using hydrogen as fuel and oxygen/air as oxidant. A typical proton exchange membrane fuel cell is generally composed of five layers that form a fuel cell membrane electrode assembly. The membrane electrode assembly includes a solid polymer electrolyte proton conducting membrane, two gas diffusion layers, and two catalyst layers. 
     Catalyst performance is directly tied to fuel cell performance. The electrochemical reactions in a fuel cell occur on the surface of active metal catalysts. Atoms in the surface of the catalyst interact with the fuel and oxidant gases, making and breaking chemical bonds. To optimize the rate of these reactions, fuel cell catalysts are synthesized with nanometer sizes to increase the surface area of the catalyst. However, traditional solution-based chemical techniques for the preparation of metal nanoparticles are typically time-consuming and labor intensive processes. 
     SUMMARY 
     Methods for the rapid synthesis of catalyst are disclosed herein. One method of the rapid synthesis of catalyst comprises first forming a solution that comprises a solvent, a precious metal precursor, a catalyst substrate, a reducing agent and a stabilizer. The solution is homogenized. The precious metal precursor is reduced to nanoparticles of the precious metal and the nanoparticles are deposited onto the catalyst substrate to form catalyst particles. Reducing and depositing comprise increasing a temperature of the solution with microwave irradiation at a controlled rate to a predetermined temperature and holding the solution at the predetermined temperature with microwave irradiation until the reduction and depositing are detected to be complete. 
     Another method of the rapid synthesis of catalyst comprises forming a homogenous solution comprising a precious metal precursor and a catalyst substrate, reducing the precious metal precursor to precious metal nanoparticles, and depositing the precious metal nanoparticles onto the catalyst substrate to form catalyst particles. The reducing and depositing steps comprise controlling a rate of increase in temperature of the solution with microwave irradiation until the solution is a predetermined temperature and maintaining the solution at the predetermined temperature with microwave irradiation. The method further comprises detecting completion of the reduction and deposition and ceasing microwave irradiation upon detection. 
     Also disclosed herein are catalyst formed with the rapid synthesis processed disclosed herein. One embodiment of a catalyst disclosed herein is an ultra-low loading catalyst prepared by a process comprising forming a solution, wherein the solution comprises a solvent, a precious metal precursor, a catalyst substrate, a reducing agent and a stabilizer. The solution is homogenized. The precious metal precursor is reduced to nanoparticles of the precious metal and the nanoparticles are deposited onto the catalyst substrate to form catalyst particles. Reducing and depositing comprise increasing a temperature of the solution with microwave irradiation at a controlled rate to a predetermined temperature and holding the solution at the predetermined temperature with microwave irradiation until the reduction and depositing are detected to be complete. 
     These and other aspects of the present disclosure are disclosed in the following detailed description of the embodiments, the appended claims and the accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The various features, advantages and other uses of the present apparatus will become more apparent by referring to the following detailed description and drawing in which: 
         FIG. 1  is a flow diagram of a method of rapidly synthesizing a catalyst as disclosed herein; 
         FIG. 2A  is a flow diagram of a method of preparing a solution used in the processes disclosed herein; 
         FIG. 2B  is a flow diagram of another method of preparing a solution used in the processes disclosed herein; 
         FIG. 2C  is a flow diagram of yet another method of preparing a solution used in the processes disclosed herein; 
         FIG. 2D  is a schematic of yet another method of preparing a solution used in the processes disclosed herein; 
         FIG. 3  is a schematic of an apparatus used to prepare catalyst with the processes as disclosed herein; 
         FIG. 4  is a schematic of another embodiment of an apparatus used to prepare catalyst with the processes as disclosed herein; 
         FIGS. 5A and 5B  are detailed schematics of an embodiment of an apparatus as disclosed herein; 
         FIG. 6  is a schematic of another embodiment of an apparatus used to prepare catalyst with the processes as disclosed herein; 
         FIG. 7  is a cyclic voltammogram comparing a commercial catalyst to a catalyst as disclosed herein; and 
         FIG. 8  is a graphic schematic comparing kinetic currents measured at 0.8V and normalized for loading (mA/mg) and volumetric activities (A/cm 3 ) of PGM catalyst, non-PGM catalyst and the ultralow loading catalyst as disclosed herein. 
     
    
    
     DETAILED DESCRIPTION 
     Traditional methods of catalyst synthesis, particularly water-based methods, produce particles that have non-uniform and non-optimal particle sizes, poor dispersion on the catalyst support, and a high degree of agglomeration. Disclosed herein are processes involving the rapid synthesis of fuel cell catalysts using controlled microwave irradiation. Also disclosed are the ultra-low loading catalyst produced by these processes. These methods produce ultra-fine metal catalyst nanoparticles with a low degree of agglomeration and good dispersion on the support, both of which contribute to optimum catalytic activity. 
       FIG. 1  is a flow diagram illustrating an embodiment of the rapid synthesis of catalyst as disclosed herein. In step  10 , a solution is prepared that comprises a solvent, a precious metal precursor, a catalyst substrate, a reducing agent and a stabilizer. The solution is homogenized in step  12 . The precious metal precursor is reduced to nanoparticles of the precious metal and the nanoparticles are deposited onto the catalyst substrate to form catalyst particles in step  14 . Reducing and depositing in step  14  can be completed by increasing a temperature of the mixture using microwave irradiation at a controlled rate to a predetermined temperature in step  16 , and holding the mixture at the predetermined temperature using microwave irradiation until the reduction and depositing are detected to be complete in step  18 . 
     As noted, the components used to prepare the solution in step  10  include a solvent, a precious metal precursor, a catalyst substrate, a reducing agent and a stabilizer. The catalyst substrate can be those catalyst substrates known to those skilled in the art and include, as non-limiting examples, various types of carbon blacks, such as Vulcan®, Ketjenblack®, Black Pearl™ and acetylene black. Other examples include raw carbon with no structured porosity or carbon precursors, carbon nanotubes, micro-pore controlled structured carbon types. The catalyst substrate can also be non-traditional, novel alternative supports such as oxygen reduction reaction-active carbon materials, conductive metal oxide particles, non-precious group metal catalysts and other materials that assist in oxygen reduction reactions. 
     The precious metal precursor can include one or a combination of precious metals such as platinum, gold, rhodium, ruthenium, palladium and iridium, and/or transition metals such as cobalt and nickel. The precious metal can be in various forms, such as alloys, nanowires, nanoparticles and coreshells, which are bimetallic catalysts that possess a base metal core surrounded by a precious metal shell. The precious metal precursor can include one or more metal co-catalysts, such as PtSnO 2 , PtSnO 2 TiO 2 , PtPdSnO 2  and PtNb 2 O s . 
     The solvent can be, as non-limiting examples, water, alcohol, polyols, and polymeric polyols. If a polyol is used as the solvent, the polyol will also perform as the reducing agent, reducing the number of raw materials required. For example, polyols such as ethylene glycol, diethylene glycol, propylene glycol, glycerol and polyethylene glycol can be used as the solvent and reducing agent to carry out the reduction of metal precursors to metallic nanoparticles. Depending on the type of precious metal precursor added to the solution, an additional reducing agent may be required. For example, a precious metal precursor containing palladium may require an additional reducing agent if ethylene glycol is used as the solvent. 
     The stabilizer added to the solution can be a surfactant or any other substance known to those skilled in the art to protect the particles from agglomeration. If particular polyols are used as the solvent and reducing agent, it is possible a stabilizer will not be needed as the polyol will also perform as the stabilizer. 
     In preparing the solution, the precious metal precursor, the solvent, the reducing agent and the stabilizer can be added in any order or contemporaneously. As a non-limiting example, the solution in step  10  can be prepared as illustrated in  FIG. 2A , where the solvent, reducing agent and stabilizer can be added to the precious metal precursor in any order or contemporaneously. The catalyst substrate can then be added to complete the solution. Alternatively, as shown in  FIG. 2B , the catalyst substrate can be added to the solvent and stabilizer to produce mixture A, and the precious metal precursor can be added to additional of the solvent and stabilizer, along with the reducing agent, to product mixture B. Mixtures A and B can be mixed together to form the solution. For example, the catalyst substrate can be mixed with ethylene glycol and the precious metal precursor can be mixed with ethylene glycol. Those two mixtures are then added together to form the solution. The ethylene glycol acts as the solvent, reducing agent and stabilizer. 
     In another aspect of the process, illustrated in  FIG. 2C , an acid can be added to a the catalyst substrate, when the catalyst substrate comprises carbon, prior to adding the precious metal precursor to optimize deposition of the precious metal precursor on the catalyst substrate. The acid facilitates the formation of acidic functional groups, which are positively charged, on the carbon in the catalyst substrate prior to reducing. The acidic functional groups assist in positioning the precious metal in the precious metal precursor, which is negatively charged, as the precious metal precursor is reduced. Acids such as perchloric acid can be used. The solvent, reducing agent, stabilizer and precious metal substrate are added after the acid. 
       FIG. 2D  is a schematic diagram illustrating producing a solution for a multi-component catalyst. In  FIG. 2D  a metal oxide is provided in step  50 , shown as tin dioxide (SnO 2 ) as a non-limiting example. A precious metal precursor, here PtCl 6   2  is added to the metal oxide in step  60 , and ethylene glycol is added in step  70  as the solvent, reducing agent and stabilizer. The chemical reaction taking place in step  70  is shown in greater detail in the bubble. The precious metal precursor is reduced to Pt 0  and forms PtSnO 2  nanoparticles in step  70 . Catalyst substrate is added to the mixture to complete the solution in step  80 . The nanoparticles are deposited on the catalyst substrate in step  90 . 
     Referring back to  FIG. 1 , in step  12 , the solution is homogenized. To homogenize the solution, any means can be used known to those skilled in the art. Examples include sonication, mixing with a magnetic bar, and the like. The homogenization assists in dispersing the catalyst substrate and precious metal precursor, which results in a more uniform loading of the catalyst particles on the catalyst substrate. 
     In step  14 , the precious metal precursor is reduced to nanoparticles of the precious metal and the nanoparticles are deposited onto the catalyst substrate to form catalyst particles. Step  14  is carried out in two parts, increasing the temperature of the solution using microwave irradiation at a controlled rate until the predetermined temperature is reached, in step  16 , and holding the solution at the predetermined temperature using microwave irradiation until the reduction and depositing are detected to be complete in step  18 . The reduction of the precious metal precursor to nanoparticles can occur in either or both of step  16  and  18 . The deposition of the nanoparticles onto the catalyst substrate occurs after reduction has initiated, so it can occur in either or both of step  16  and  18  so long as reduction has been initiated. 
     During steps  16  and  18 , the metal salts, oxides, and other complexes in the catalyst precursor are reduced by the reducing agent at elevated temperatures. For example, metal ions are reduced to their metallic elemental state by receiving electrons from the oxidation of the reducing agent. The stabilizer adsorbs on the metal nanoparticle surface and provides electrostatic repulsive forces between metal nanoparticles to prevent particle agglomeration. As a non-limiting example, ethylene glycol can be used as the solvent, reducing agent and stabilizer. The precious metal ions in the precious metal precursor, for example PtCl 6   2- , are reduced to their metallic elemental state Pt 0  by receiving electrons from the oxidation of ethylene glycol to glycolic acid. Glycolic acid becomes glycolate in alkaline or basic solutions. The glycolate anions adsorb on the metal nanoparticle surface and act as stabilizers by providing electrostatic repulsive forces between metal nanoparticles to prevent particle agglomeration. 
     In step  16 , the temperature of the solution is increased from room temperature to a predetermined temperature of up to about 300° C., and in particular, about 180-200°C., using microwave irradiation. The temperature is increased at a controlled rate, with the rate selected from between about 8° C./minute to about 12° C./minute. The controlled rate prevents superheating of a portion or all of the solution and provides for more uniform reduction and deposition. 
     When the predetermined temperature is reached, the solution is held at the predetermined temperature using microwave irradiation until the reduction and depositing are detected to be complete in step  18 . 
     The detection of the reduction and depositing being complete can be achieved by detecting when a predetermined period of time has elapsed. When the predetermined period of time has elapsed, the microwave irradiation will cease. Alternatively, visual detection of a color change of the solution can detect the completion of reduction and deposition. As non-limiting examples, the solution can begin as a nearly transparent solution with the completion of the reduction and deposition detected when the solution has turned opaque, and/or the solution can begin as a colored solution such as orange with the completion of the reduction and deposition detected when the solution has turned black. As an alternative or addition to visual detection, a light emitter and detector can be used to detect when the solution turns from transparent to opaque. 
     The microwave irradiation can be provided with a microwave oven or with directed microwave beams. An apparatus disclosed herein uses a microwave oven for more uniform heating. 
     Referring back to  FIG. 1 , the solution can be cooled to room temperature in step  20 . Once cooled, the catalyst particles are washed in step  22  to remove impurities. For example, the catalyst particles may be washed a number of times with deionized water to remove chloride ions from the catalyst particles along with other impurities. 
     During step  14 , reducing and depositing, additives may be added to the solution. For example, additional surfactants, stabilizers or dispersants can be added. Additional reducing agents may be added to the solution if a stronger reducing agent is required, such as NaBH 4  Additional metal precursors can also be added in the middle of the synthesis, such as additional transition metals and/or precious metals when the resulting catalyst particles are to be alloys or core-shell morphologies. 
     Also disclosed are embodiments of an apparatus for the rapid synthesis of catalyst by the methods disclosed herein. As shown in  FIG. 3 , the apparatus  100  can comprise a microwave radiation generator  102  with a reaction chamber  104  positioned relative to the microwave radiation generator  102  to receive microwave radiation. A temperature probe  106  is configured to detect a temperature within the reaction chamber  104 . A reflux condenser  108  is in fluid communication  110  with the reaction chamber  104  and is positioned relative to the microwave radiation generator  102  to avoid microwave radiation of the reflux condenser  108 . A controller  112  is configured to receive the temperature within the reaction chamber  104  from the temperature probe  106  and control production of microwave radiation by the microwave radiation generator  102  based on the temperature received from the temperature probe  106  to increase the temperature of the reaction chamber  104  at a controlled rate until a predetermined temperature is reached. The controller  112  is also configured to control production of microwave radiation by the microwave radiation generator  102  to maintain the temperature of the reaction chamber  104  at the predetermined temperature until the reduction and depositing are detected to be complete. 
     In  FIG. 3 , the microwave radiation generator  102  is illustrated as a microwave oven.  FIG. 4  illustrates another aspect of the embodiment of  FIG. 3 . In  FIG. 3 , the microwave radiation generator is a microwave laser  114  and the reaction chamber  104  is positioned within a beam  116  of the microwave laser. The reflux condenser  108  is positioned outside of the beam  116  of the microwave laser  114 . 
     As noted, the detection of the completion of the reduction and deposition can be done in a number of ways.  FIG. 3  illustrates the use of a light emitter  120  and light detector  122  to detect when the solution turns from transparent to opaque. The light emitter  120  emits light through the reaction chamber  104  and the light detector  122  monitors the amount of light that passes through the reaction chamber  104  and sends the information to the controller  112 . The controller  112  will request the microwave irradiation stop when the light detector  122  indicates that the solution is opaque. The light emitter  120  and light detector  122  can be used with any embodiment disclosed herein. 
       FIGS. 5A  and B are detailed illustrations of an embodiment of an apparatus  200  for the rapid synthesis of catalyst by the methods disclosed herein. In this embodiment, the microwave radiation generator is a microwave oven  202 . As a non-limiting example, an industrial microwave oven can be used having an output power of approximately 1000 microwave watts and an operating frequency of approximately 2.45 GHz. The microwave oven  202  has a cavity  204 , which can have corrosion-resistant stainless steel walls. The microwave oven  202  provides even microwave radiation distribution for uniform heating with no or minimal hot spots. The cavity  204  can also have a powered exhaust fan to remove fumes, preventing any gas build-up in the cavity  204 .  FIG. 5A  illustrates the cavity  204  enclosed by a door  206  of the microwave oven  202 . 
     The reaction chamber  208  is positioned within the cavity  204  of the microwave oven  202 . The reaction chamber  208  can be a reaction flask made from glass or other inert material. The reflux condenser  210  is positioned outside of the microwave oven  202  and is connected to the reaction chamber  208  with an adapter  212  extending through an aperture  214  in a wall  216  of the microwave oven  202 . The adapter  212  can be sized to fit with a sealable engagement to a neck of the reaction chamber  208 , for example. The adapter  212  is configured to prevent radiation leakage from the microwave oven  202 , such as with seal  218  made of material such as Teflon®, for example. The reflux condenser  210  can be equipped with a liquid circulator  222  configured to control a temperature of liquid circulated through the reflux condenser  210 . 
     The temperature probe  220  is configured to measure the temperature of the solution in the reaction chamber  208 . The reaction chamber  208  can have a port sized and configured to receive the temperature probe  220 . The microwave oven  202  can have a built-in microwave-safe temperature probe  220  containing a thermocouple embedded within a stainless steel tube, as a non-limiting example. 
     The temperature probe  220  provides the temperature of the solution in the reaction chamber  208  to a controller  224 , such as a central processing unit. The controller  224  can be a separate unit in communication with the microwave oven  202  or can be integrated within the microwave oven  202 . The controller  224  interfaces with the temperature probe  220  to monitor and control the solution temperature. Heating is controlled by feedback from the temperature probe  220  of the solution temperature to the controller  224 . The controller  224  is programmed to increase the temperature of the solution in the reaction chamber  208  at a controlled rate between about 8° C./minute to about 12° C./minute until a predetermined temperature is reached at which the solution will soak. The predetermined temperature is below about 300° C., and particularly between about 180° C. and 200° C. When the predetermined temperature is reached, the controller  224  compares the solution temperature to the predetermined temperature. If the sample temperature is too low, the controller  224  calls for microwave radiation to maintain the solution at the predetermined temperature. If the solution temperature is too high, the controller  224  ceases microwave radiation to maintain the solution at the predetermined temperature. These steps are repeated by the controller  224  until the reduction and depositing are detected to be complete. 
     The controller  224  can have a control panel  226  configured to receive input from the user, such as the rate at which the temperature should be increased, the predetermined temperature and the predetermined period of time. The controller  224  can be preprogrammed with options such that the user will use the control panel  226  to select the required parameters. The control panel  226  can display any information desirable, such as current temperature of the solution, target predetermined temperature, time period lapsed, etc. 
     The apparatus  200  can also include a sealable portal  230  configured to allow introduction of material to the reaction chamber  208  during irradiation. As non-limiting examples, the adapter  212  can have a second portal extending in a Y-shape that can be separately sealed and through which material can be added, or the reaction flask  208  itself can have a second portal extending there from and through a second aperture within the microwave oven  202  wall  216 . 
       FIG. 6  is another embodiment of an apparatus  300  for the rapid synthesis of a plurality of catalysts by the methods disclosed herein. In this embodiment, the apparatus  100 ,  200  as disclosed herein can be altered so that a plurality of the same catalyst can be made simultaneously or a plurality of different types of catalyst can be made simultaneously.  FIG. 6  is a schematic of  FIG. 3  with additional components described herein. 
     A plurality of reaction chambers  308  are positioned within the cavity  304  of the microwave oven  302 . The three reaction chambers  308  shown in  FIG. 6  are provided as an example and is not meant to limit the number of reaction chambers  308 . Reflux condensers  310  are positioned outside of the microwave oven  302  and are each connected to a respective reaction chamber  308  with an adapter  312  extending through respective apertures  314  in a wall  316  of the microwave oven  302 . Each reflux condenser  310  can be equipped with a liquid circulator  322  configured to control a temperature of liquid circulated through the reflux condenser  310 . 
     Each reaction chamber  308  has a temperature probe  320  configured to measure the temperature of the solution in the associated reaction chamber  308 . Each temperature probe  320  provides the temperature of the solution in its associated reaction chamber  308  to a controller  324 , which interfaces with the temperature probes  320  to individually monitor and control the solution temperature in each reaction chamber  308 . Heating of each reaction chamber  308  is controlled by feedback from its temperature probe  320  of the solution temperature to the controller  324 . The controller  324  is programmed to increase the temperature of the solution in each reaction chamber  308  at a controlled rate, which can be the same for each reaction chamber  308  or different based on user selection. When the predetermined temperature is reached for the individual reaction chamber  308 , the controller  324  compares the solution temperature to the predetermined temperature. If the sample temperature is too low, the controller  324  calls for microwave radiation to maintain the solution at the predetermined temperature. If the solution temperature is too high, the controller  324  ceases microwave radiation to maintain the solution at the predetermined temperature. These steps are repeated by the controller  324  until the reduction and depositing are detected to be complete. 
     Unlike traditional catalyst preparation apparatus methods, the apparatus and methods disclosed herein provide uniform and even heating of the solution, rapid heating of the solution leading to shortened reaction times, energy-efficiency due to the shortened reaction times and shortened times required to heat, and rapid, one-pot synthesis of novel fuel cell catalysts. 
     Also disclosed herein are catalysts formed with the rapid synthesis processes disclosed herein. The catalyst can be formed using the apparatus disclosed herein. 
     For example, to synthesize a catalyst having 50 wt % platinum on carbon support, 250μL of a 1.0M H 2 PtCl 6  precious metal precursor dissolved in ethylene glycol was mixed with 50 mg Ketjen Black® and 25 mL ethylene glycol. The solution was sonicated for thirty minutes in a reaction chamber to form a homogeneous solution. The reaction chamber was connected to the adapter of the reflux condenser in a microwave oven and heated at a controlled rate of 10° C./minute. The solution was heated to a predetermined temperature of 190° C. and was kept at that temperature for three minutes. The resulting catalyst was then allowed to cool to room temperature and subsequently washed five times with deionized water to remove chloride ions and other impurities. 
       FIG. 7  is a cyclic voltammogram (CV) comparing the catalyst produced in the example above with commercially purchased catalyst having 50 wt % Pt on Ketjen Black® support. This CV comparison confirms the viability of the disclosed processes and apparatus in making commercially acceptable catalyst. 
     Another embodiment of a catalyst disclosed herein is an ultra-low loading catalyst prepared by processes disclosed herein. 
     A non-limiting example of an ultralow loading catalysts disclosed herein comprises support particles of a non-precious group metal (non-PGM) catalyst and precious metal particles supported on the support particles. The non-PGM catalyst is used for the dual functions of support and active catalyst sites. By depositing a small amount of precious metal nanoparticles on non-PGM catalyst support, the cost of the resulting catalyst is reduced while the catalytic activity or performance is increased. The catalytic activity is improved by the addition of single active sites provided by the precious metal nanoparticles, providing more active sites for fuel cell oxygen reduction reaction while keeping increases in volume and price minimal. The ultralow loading catalyst is a non-limiting example and other combinations of the precious metal precursor and catalyst substrate disclosed herein and known to those skilled in the art can be used. 
     The precious metal nanoparticles have a diameter in the range of two to ten nanometers, or more particularly two to four nanometers. Although the smallest practicable nanoparticles are desired, nanoparticles of precious metal less than 2 nanometers tend to be unstable with regard to agglomeration. 
     The processes disclosed herein result in an ultralow loading catalyst with uniformly distributed precious metal nanoparticles on a surface of the catalyst substrate. The ultralow loading catalyst made by the processes herein has a precious metal loading of less than fifteen weight percent. Various precious metal weight percent loaded catalysts can be synthesized, with the minimum and maximum precious metal loading dictated by the structure of the particles used to prepare the ultralow loading catalyst. However, ultralow loading catalyst disclosed herein has been synthesized with a precious metal loading of less than five weight percent. 
     An example of an ultralow loading catalyst as disclosed herein having five weight percent platinum on a non-PGM catalyst is prepared as follows. 5.25 mg H 2 PtCl 6 , a platinum precursor, was mixed with 47.5 mg non-PGM catalyst as the catalyst substrate in 25 mL ethylene glycol. The solution was sonicated for thirty minutes to form homogeneous slurry in a reaction chamber. The reaction chamber was transferred to a microwave oven and attached to the reflux condenser and heated at a controlled ramp rate of 10° C./minute to a predetermined temperature of 190° C. The solution was kept at 190° C. for a predetermined time of three minutes. The resulting catalyst was then allowed to cool to room temperature and subsequently washed five times with deionized water to remove chloride ions and other impurities. 
     Two metrics, kinetic currents measured at 0.8V and normalized for loading (mA/mg) and volumetric activities (A/cm 3 ), are used to compare the activity of the ultralow loading catalyst with non-PGM catalyst alone. As shown in  FIG. 8 , the ultralow loading catalyst having a platinum presence on non-PGM catalyst support exhibits higher kinetic current and volumetric activity than a non-PGM catalyst. 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.