Fabrication of 3D nanostructured electrocatalysts for fuel cell electrodes via proximity-field nanoPatterning

Abstract

Ordered porous nanostructures are attractive for various electrochemical applications because of their structural advantages: relatively large surface areas, interconnected pores, and high diffusion rates of reactants. First, the three dimensional carbon supports, decorated with platinum nanoparticles, were made by the supported alumina shell carbonization process of the SU8 photoresist. The differences between the shrinkages of the alumina and the photoresist made the large porosity on its surface, and the platinum nanoparticles decorated the carbon supports successfully by the confined activation process. Second, hierarchically porous platinum nanostructures were derived from the dealloying process of nickel-rich $Ni_{80}Pt_{20}$ alloys. The nickel and platinum atoms moved during the dealloying process, and there were tiny nanopores because of the slow surface diffusion rate of platinum. The hierarchically porous platinum nanostructures were free from the degradation of the carbon supports and reduced the amount of platinum per unit area. Herein, we fabricated these two nanostructured electrocatalysts and saw the possibility of the usage for fuel cell electrodes by the oxygen reduction reaction test. We expected that compared with the conventional electrocatalysts, these ordered porous nanostructures improve the effective porosity, the mass transfer, and the water management owing to their structural advantages. Moreover, the pores on the hierarchically porous nanostructures are totally interconnected

therefore, they were expected to enhance the electrical conductivity, electrochemical surface area, and platinum utilization.