Enhanced electrocatalytic water splitting activity by modulating the catalytic microenvironment with incorporated rhenium atoms in metal organic frameworks derived cobalt phosphide

Modulating the catalytic microenvironment has emerged as a highly effective strategy for developing high-performance catalysts. In this study, a microenvironment modulation strategy is successfully implemented by incorporating rhenium (Re) atoms into metal organic frameworks (MOFs)-derived cobalt phosphide (Co₂P). This results in the production of a high-performance electrocatalyst of Re-Co₂P for overall water splitting (OWS). Owing to the incorporated Re atoms, the catalytic microenvironment is effectively regulated, and the conductivity and electron transfer are improved as well. As a result, the optimized Re-Co₂P catalyst exhibits outstanding catalytic activities, manifested as the low overpotentials of 57 and 235 mV under 10 mA cm⁻² for hydrogen and oxygen evolution reactions, and a small cell voltage of 1.50 V under 10 mA cm⁻² for OWS. Experimental characterizations and density functional theory calculations reveal that Re incorporation in Co₂P regulates the electronic structure, facilitates the charge transfer, and optimizes the Gibbs free energy, thereby improving the water splitting efficiency. This work demonstrates an efficient strategy to construct OWS electrocatalysts by regulating the catalytic microenvironment through the incorporation of metal atoms into MOFs-derived materials.