P-block Bi doping stabilized reconstructed nickel sulfide as high-performance electrocatalyst for oxygen evolution reaction

Turning the chemical state of in-situ converted oxyhydroxides is essential for the development of efficient oxygen evolution reaction (OER) catalysts. In this work, P-block element Bi is first introduced as a dopant to tune the in-situ reconstruction of Ni 3 S 2 pre-catalyst towards enhanced OER activity. Analysis revealed that Bi doping adjusts the electronic structure of Ni 3 S 2 , improves its stability, and leads to mild surface oxidation forming supported Bi-NiOOH species. Theoretical calculations showed that Bi dopant serves as electron depletion center to provide electrons for Ni and O, and reduces the energy barriers of OER intermediates. Consequently, a low OER overpotential of 339 mV is achieved by the Bi-Ni 3 S 2 /NF electrode in 1M KOH at 100 mA cm −2 . More importantly, Bi-Ni 3 S 2 -NF retains a high catalytic stability even at 200 mA cm −2 . This work unveils the role of P-block metal doping on the sulfide-based OER pre-catalyst, providing an alternative strategy for the development of high-performance electrocatalysts.