Manganese‐Doped Bimetallic (Co,Ni)₂P Integrated CoP in N,S Co−Doped Carbon: Unveiling a Compatible Hybrid Electrocatalyst for Overall Water Splitting

Abstract

Rational design of highly efficient noble‐metal‐unbound electrodes for hydrogen and oxygen production at increased current density is crucial for robust water‐splitting. A facile hydrothermal and room‐temperature aging method is presented, followed by chemical vapor deposition (CVD), to create a self‐sacrificed hybrid heterostructure electrocatalyst. This hybrid material, (Mn−(Co,Ni)2P/CoP/(N,S)−C), comprises manganese‐doped cobalt nickel phosphide (Mn−(Co,Ni)2P) nanofeathers and cobalt phosphide (CoP) nanocubes embedded in a nitrogen and sulfur co‐doped carbon matrix (N,S)−C on nickel foam. The catalyst exhibits excellent performance in both the hydrogen evolution reaction (HER; η10 = 61 mV) and oxygen evolution reaction (OER; η10 = 213 mV) due to abundant active sites, high porosity, and enhanced hetero‐interface interaction between Mn−(Co2P−Ni2P) CoP, and (N,S)−C supported by significant synergistic effects observed among different phases through density functional theory (DFT) calculations. Impressively, (Mn−(Co,Ni)2P/CoP/(N,S)−C (+,−) shows an extra low cell voltage of 1.49 V@10 mA cm−2. Moreover, the catalyst exhibits remarkable stability at 100 and 300 mA cm−2 when operating as a single stack cell electrolyzer. The superior electrochemical activity is attributed to the enhanced electrode–electrolyte interface among the multiple phases of the hybrid structure.

Synergetic Catalytic Effect between Ni and Co in Bimetallic Phosphide Boosting Hydrogen Evolution Reaction

“…Recent studies have shown that the addition of heterogeneous metals can alter the electronic structure of monometallic phosphides, thereby improving their catalytic efficiency [18][19][20]. On this basis, we constructed a bimetallic NiCoP heterojunction to modulate the intrinsic electronic distribution and enhance the H* coverage on the catalyst surface during HER under alkaline conditions, making NiCoP a promising candidate for efficient HER catalysis.…”