Preparation of S-doped CuCoO2 nanosheets with more oxygen defects for efficient oxygen evolution reaction†

Noble metal catalysts are excellent oxygen evolution reaction (OER) catalysts, but the expensive price and scarce reserves constrain the development of water splitting. CuCoO₂ is known as a promising catalytic material due to its abundant raw materials and unique structure. However, its OER performance requires further enhancement. In this research, S-doped CuCoO₂ nanocrystals were synthesized through a one-step solvothermal method. The electrochemical test results revealed that 0.33 mmol S doped CuCoO₂ (CCOS-3) exhibits superior catalytic activity (η₁₀ = 375.5 mV, Tafel slope = 83.4 mV dec⁻¹) in 1.0 M KOH electrolyte. Furthermore, after an 18 hours OER stability test, the CCOS-3 exhibited a minimal overpotential degradation of 27 mV. Brunauer–Emmett–Teller (BET) tests showed that the surface area of CCOS-3 is 12.51 m² g⁻¹. X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible-near infrared (UV-Vis-NIR) absorption spectra results revealed that S doping boosts the quantity of oxygen defect sites and narrows the band gap of CuCoO₂. Therefore, the charge transfer within the material is accelerated and the catalytic activity is optimized. This work may offer a novel insight into enhancing the OER performance of CuCoO₂ catalysts through nonmetallic doping.