Construction of CoNiSSe-g-C3N4 nanosheets with high exposed conductive interface for boosting oxygen evolution reaction

•A comparative study of electron transfer from bimetallic Co/Ni and monometallic Co active sites to a large amount of pyridine-N in the potential g-C3N4 to promote oxygen evolution reactions.•XPS indicated that metal Ni-N bonds were formed between CoNiSSe and g-C3N4, which compared with no Ni-N covalent bonds between CoSSe and g-C3N4.•The bimetallic CoNiSSe@g-C3N4 hybrid electrocatalysts demonstrated remarkable performance toward OER with an overpotential of 282 mV (1.512 V vs. RHE) at 10 mA cm–2 and a Tafel slope of 59 mV dec–1, which exhibited considerable current densities, small overpotentials, and satisfactory stabilities.•Theoretical calculations demonstrate that the CoNiSSe@g-C3N4 at the Fermi level is significantly increased. The high DOS of CoNiSSe@g-C3N4 indicates that more charge carriers can directly participate in the catalytic reaction, which can help to improve OER performance. [Display omitted] Herein, the design and manufacture of electrocatalysts based on bimetallic CoNiSSe-g-C3N4 and monometallic CoSSe-g-C3N4 are reported. A comparative research of electron transfer from bimetallic Co/Ni and monometallic Co active sites to a large amount of pyridine-N in the potential g-C3N4 to promote oxygen evolution reactions. The CoNiSSe-g-C3N4 hybrid electrocatalysts exhibited nanosheet morphology and have an average thickness of 0.92 nm. XPS indicated that metal Ni-N bonds were formed between CoNiSSe and g-C3N4, which compared with no Ni-N covalent bonds between CoSSe and g-C3N4. Meanwhile, the integration of g-C3N4 provides a 2D g-C3N4 matrix for high-efficient interfacial charge transfer. The bimetallic CoNiSSe-g-C3N4 electrocatalysts demonstrated distinguished performance toward OER accompanied by an overpotential of 282 mV (1.512 V vs. RHE) at 10 mA cm–2, Tafel slope 59 mV dec–1, which exhibited excellent current densities, small overpotentials, and good stabilities. Theoretical calculations demonstrate that the DOS intensity of the Fermi level is closely related to the conductivity of the electrocatalysts, which indicates rapid charge transfer kinetics, electron transfer process.