Synthesis of strontium-incorporation SnO₂ for oxygen evolution reaction

Modulating the electronic structure of metal oxides is an effective strategy to enhance the electrocatalytic oxygen evolution reaction (OER). Shifting the conduction band (CB) to more negative potentials facilitates interfacial charge transfer, improving OER kinetics. Here, strontium (Sr) is incorporated into SnO₂ to shift the CB, induce lattice strain, and generate oxygen vacancies. Structural and electrochemical analyses reveal that intermediate Sr incorporation optimally balances electronic modulation and defect density, yielding the highest OER activity. This catalyst delivers an overpotential of 430 mV at 10 mA cm^-2, a Tafel slope of 68 mV dec^-1, and stable operation over 5.2 h in 1.0 M KOH. The enhanced performance is driven primarily by improved interfacial charge transfer kinetics rather than benchmark intrinsic activity. This work demonstrates how aliovalent doping tunes the band structure and defect chemistry of cost-effective oxides, providing a scalable strategy for designing non-precious metal water splitting catalysts.