Interfacial electron modulation enables synergistic enhancement of IrNi/Ni(OH)2 for bifunctional overall water splitting

The development of highly efficient and low-cost bifunctional catalysts is pivotal for the large-scale commercialization of water electrolysis technology. A solvothermal method was used to fabricate the bifunctional Ir 0.1 Ni/Ni(OH) 2 electrocatalyst, utilizing Ni(OH) 2 which served as both the support and the nickel (Ni) source for the in-situ formation of IrNi alloy nanoparticles via co-reduction. The significant electronegativity difference between iridium (Ir) and Ni induced electron transfer from Ni to Ir at the alloy interface, resulting in substantial interfacial electronic reconstruction. This electronic synergy optimally regulated the bifunctional activity: the electron-rich Ir sites facilitated the adsorption of hydrogen intermediates, enhancing the hydrogen evolution reaction; whereas the electron-deficient Ni sites strengthened the adsorption of hydroxyl and oxygen intermediates (OH, OOH*), significantly lowering the energy barrier for the oxygen evolution reaction. Therefore, this catalyst exhibits excellent activity and stability in both the OER and the HER. In a 1.0 M KOH solution at a current density of 10 mA cm −2 , the HER requires an extremely low overpotential of only 31 mV, while the OER requires 270 mV. Moreover, Ir 0.1 Ni/Ni(OH) 2 serves as an electrocatalyst for overall water splitting in alkaline media. This research provides a simple and effective strategy for designing advanced alloy catalysts for sustainable energy conversion.