Cobalt-regulation-induced dual active sites in Ni2P for hydrazine electrooxidation

Abstract

Better understanding of electrochemical reaction behaviors of hydrazine electrooxidation at metal phosphides has long been desired and the optimization of reaction kinetics has been proved to be operable. Herein, the dehydrogenation kinetics of hydrazine electrooxidation at Ni2P is adjusted by Co as the (Ni0.6Co0.4)2P catalyzes HzOR effectively with onset potential of –45 mV and only 113 mV is needed to drive the current density of 50 mA cm–2, showing over 60 mV lower than Ni2P and Co2P. It also delivers the maximum power density of 263.0 mW cm–2 for direct hydrazine fuel cell. Detailed experimental results revealed that Co doping not only decreases the adsorption energy of N2H4 on Ni sites, lowering the energy barrier for dehydrogenation, but also acts as the active sites in the optimal reaction coordination to boost the reaction kinetics. This work represents a breakthrough in improving the catalytic performance of non-precious metal electrocatalysts for hydrazine electrooxidation and highlights an energy-saving electrochemical hydrogen production method.