Tailoring the d-band center of iridium-doped cobalt selenide for dual-boosted hydrogen and oxygen evolution reactions

Designing effective electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential for the advancement of water electrolysis. Herein, iridium-doped CoSe2 (Ir–CoSe2) nanobelts with tailored d-band center are designed to boost both HER and OER in alkaline electrolytes. On the one hand, the adsorption ability of H2O and hydrogen on Ir–CoSe2 is increased due to the upshifted d-band center induced by the electron transfer from CoSe2 to Ir, inducing good HER activity with an overpotential of 126 ​mV at 10 ​mA ​cm−2. On the other hand, the upshifted d-band center of Ir–CoSe2 facilitates the H2O adsorption and ensures the effective exposure of real active sites, resulting in good OER activity with an overpotential of 239 ​mV at 10 ​mA ​cm−2. Meanwhile, when using Ir–CoSe2 as catalysts for alkaline overall water splitting on both HER and OER, a lower voltage of 1.57 ​V at 10 ​mA ​cm−2 is achieved, indicating a good activity and great potential for practical water electrolysis. This work gives an effective method for the rational design of electrocatalysts with customized d-band structures for bifunctional catalysis.