Low-Loading Platinum Alloy Electrocatalyst Supported on Hollow Carbon for the Four-Electron Oxygen Reduction Reaction

Abstract

The oxygen reduction reaction (ORR) at the cathode of proton exchange membrane fuel cell is a very slow reaction. Therefore, Pt-based catalyst is only applied to practical application. Since Pt-based noble metals are very expensive, research is underway to reduce the amount of noble metals or to replace Pt-based noble catalysts. To reduce the total production cost of fuel cells, it is required to develop a simple fabrication process with mass-productivity as well as to reduce the use of noble metals. Metal-organic framework (MOFs)-derived catalyst has been investigated as ORR catalyst due to its significantly large surface area and open pore structure. MOFs-based electrocatalyst still showed low catalytic activity and stability compared to commercial platinum based catalyst. To solve this problem, a small amount of precious metal has been added to the MOFs to maximize the performance of the MOF-based electrocatalyst. In this study, we synthesized ultra-low loading Pt@Co-NC electrocatalyst supported on MOF-derived hollow carbon. Hollow carbon was prepared by carbonization of MOF@MOF core-shell structure. After carbonization, platinum is loaded by polyol method and finally PtCo-N-C electrocatalyst was successfully synthesized through annealing process. Synthesized PtCo-N-C catalysts showed high ORR performance and four-electron selectivity in acidic condition.