Phosphorus Incorporation into Co9S8 Nanocages for Highly Efficient Oxygen Evolution Catalysis

Abstract The improvement of activity of electrocatalysts lies in the increment of the density of active sites or the enhancement of intrinsic activity of each active site. A common strategy to realize dual active sites is the use of bimetal compound catalysts, where each metal atom contributes one active site. In this work, a new concept is presented to realize dual active sites with tunable electron densities in monometal compound catalysts. Dual Co 2+ tetrahedral (Co 2+ (T d )) and Co 3+ octahedral (Co 3+ (O h )) coordination active sites are developed and adjustable electron densities on the Co 2+ (T d ) and Co 3+ (O h ) are further achieved by phosphorus incorporation (P‐Co 9 S 8 ). The experimental results and density functional theory calculations show that the nonmetal P doping can systematically modulate charge density of Co 2+ (T d ) and Co 3+ (O h ) in P‐Co 9 S 8 and simultaneously improve the electrical conductivity of Co 9 S 8 , which substantially enhances oxygen evolution reaction performance of P‐Co 9 S 8 .