Synthesis of cube-shaped PtFeNiCuCo alloy catalyst towards high performance alkaline hydrogen evolution

Abstract

The commercialization of hydrogen fuel cell technologies requires high-performance and low-cost catalysts for production of highly pure hydrogen from electrochemical water splitting. In this work, cube-shaped multicomponent alloy catalysts PtFeNiCu and PtFeNiCuCo supported on carbon nanotubes were synthesized by one-step wet chemical reduction method. Powder X-ray diffraction analysis and transmission electron microscope imply the successful synthesis of alloy catalysts. The particle size of PtFeNiCu and PtFeNiCuCo is determined to be around 12.6 nm. The impact of the Co-doping into the PtFeNiCu alloy on the structural defects and catalytic performance towards alkaline hydrogen evolution (HER) was explored. It is observed the Co-doping into PtFeNiCu alloy induces sufficient decrease of the crystalline size and enhancement of the microstrain and stacking defects, as revealed by the Williamson-Hall method. It was observed that the overpotential for PtFeNiCuCo at the current density of 10 mA/cm2 in 1 M KOH is only 27 mV and Tafel slope is 34.7 mVdec1, superior to that of PtFeNiCu and commercial Pt/C. Such enhanced electrocatalytic performance was ascribed to the extensile strain and surface defects induced by the Co-doping and the synergistic effect of Co and other metal elements.