摘要
Designing highly active,durable,and nonprecious metal-based bifunctional electrocatalysts for overall water electrolysis is of urgent scientific importance to realize the sustainable hydrogen production,which remains a grand challenge.Herein,an innovative approach is demonstrated to synthesize flower-like 3D homogenous trimetallic Mn,Ni,Co phosphide catalysts directly on nickel foam via electrodeposition followed by plasma phosphidation.The electrochemical activity of the catalysts with varying Mn:Ni:Co ratios is assessed to identify the optimal composition,demonstrating that the equimolar trimetallic phosphide yields an outstanding HER catalytic performance with a current density of 10 mA cm^(-2) at an ultra-low overpotential of~14 mV,outperforming the best reported electrocatalysts.This is asserted by the DFT calculations,revealing strong interaction of the metals and the P atom,resulting in enhanced water activation and optimized G_(H)^(*)values for the HER process.Moreover,this optimal composition appreciably catalyzes the OER by exposing more intrinsic active species in-situ formed on the catalyst surface during the OER.Therefore,the Mn_(1)-Ni_(1)-Co_(1)-P-(O)/NF catalyst exhibits a decreased overpotential of~289 mV at 10 mA cm^(-2).More importantly,the electrocatalyst sustains perfect durability up to 48 h at a current density of 10 mA cm^(-2) and continued 5000 cycling stability for both HER and OER.Meanwhile,the assembled MNC-P/NF||MNC-P/NF full water electrolyzer system attains an extremely low cell voltage of 1.48 V at 10 mA cm^(-2).Significantly,the robust stability of the overall system results in a remarkable current retention of~96%after a continuous 50-h run.Therefore,this study provides a facile design and a scalable construction of superb bifunctional ternary MNC-phosphide electrocatalysts for efficient electrochemical energy production systems.
