Tailoring the d-band center of porous CoS2 nanospheres via low-electronegative Fe for weakened OH* adsorption and boosted oxygen evolution

The development of high-performance metallic cobalt pyrite OER catalysts with suitable electronic structures remains a challenge. In this paper, a low-electronegative Fe-substituted cobalt pyrite (FexCo1-x)S-2 OER catalyst with controllable morphology and electronic structure was designed and prepared, and it exhibited excellent catalytic activity owing to the conversion of (FexCo(1-x))S-2 to Fe-CoOOH during the OER process. Benefiting from the morphology of porous nanospheres and the modulated electronic structure, Fe0.25Co0.75OOH exhibits an OER overpotential of 274 mV and a Tafel slope of 33.6 mV dec(-1) at a current density of 10 mA cm(-2). Experimental and theoretical calculation methods show that the introduction of Fe into CoOOH can modulate the d-band center of the Co site because the low electronegativity of Fe induces charge aggregation at the Co site to optimize the binding energy between Co and oxygen-containing intermediates. This study provides prospective insights into understanding the synergistic effects of bimetals in the (FexCo1-x)S-2 system and offers a new strategy for exploring other efficient catalysts with controllable electronic structures and controllable morphologies.

Automated summary

A low-electronegative metallic cobalt pyrite OER catalyst was designed and prepared in this study, showing excellent catalytic activity. The introduction of Fe can modulate the electronic structure of Co site and optimize the binding energy between Co and oxygen-containing intermediates.