Composition tuning of Ni2P@MxP-Fe2P (M = Mn, Cu, Co) heterostructures in an N and P co-doped porous carbon matrix for efficient oxygen evolution reaction.

Achieving highly efficient and stable non-noble electrocatalysts for the oxygen evolution reaction (OER) is of paramount importance for practical electrochemical water splitting. Herein, we report a series of Ni2P@MxP-Fe2P/NPC (M = Mn, x = 1; Cu, x = 3; Co, x = 2; NPC = N and P co-doped porous carbon) catalysts fabricated via a self-assembly-phosphorization strategy, derived from core-satellite Ni-MOF@MFe-PBA (M = Mn, Cu, Co) heterostructures. In the Ni2P@MxP-Fe2P/NPC hybrid architecture, core-satellite Ni2P@MxP-Fe2P hybrid are uniformly embedded within the NPC matrix, respectively. Experimental investigations reveal that the interfacial electron transfer between diverse phosphide species and the NPC matrix together with abundant active species render these catalysts with excellent OER activity in alkaline media, surpassing that of the benchmark noble metal catalyst RuO2. Notably, the Ni2P@Co2P-Fe2P/NPC catalyst requires a low overpotential of 274 mV to deliver a current density of 10 mA cm-2 and presents a Tafel slope of 45.2 mV dec-1, outperforming both Ni2P@MnP-Fe2P/NPC and Ni2P@Cu3P-Fe2P/NPC counterparts. Theoretic calculations demonstrate that the superior OER performance of Ni2P@Co2P-Fe2P/NPC originates from its optimized modulation of the ⁎OOH oxidation step due to the Co2P-induced electronic perturbation, which is favorable for accelerating OER kinetics. This work provides insightful guidance for rational designing multicomponent electrocatalysts via a metal-organic framework (MOF)-on-MOF-derived strategy, paving the way for advanced OER electrocatalysts.