p-Cu(OH)2/n-SrTiO3 Heterojunction for Efficient Photocatalytic Hydrogen Production

Improving the efficiency of well-known photocatalysts in the hydrogen evolution reaction is contingent upon the development of cost-effective and highly efficient co-catalysts. The rapid recombination of photogenerated charges within semiconductor materials, such as SrTiO₃ (STO), results in reduced photocatalytic efficiency. To address this, copper-based co-catalysts have garnered considerable attention due to their relative low-cost, natural abundance of constituents, and promising reactivity. In this work, p-Cu(OH)₂/n-SrTiO₃ heterojunctions are prepared for efficient photocatalytic hydrogen production. The SrTiO₃ photocatalysts with a flower-like morphology decorated with Cu(OH)₂ at different weight percentages of Cu (0.1, 0.5, 1, 2, and 5 wt.%) are successfully prepared using a simple solvothermal and photodeposition process. The p-Cu(OΗ)₂/n-SrTiO₃ composite with 1 wt.% Cu content exhibits significant enhancement toward photocatalytic hydrogen production compared to the pristine STO, achieving a rate of ∼139 µmol h⁻¹ (∼6950 µmol g⁻¹ h⁻¹ mass activity) under λ > 360 nm light irradiation which is ≈3.5 times higher than that of single-component STO. X-ray photoelectron spectroscopic studies indicate formation of Cu(OH)₂ phase. Moreover, UV–vis/NIR, EIS spectroscopy, and photocatalytic evaluation studies indicate that the improved photocatalytic performance arises from the formation of p-n junction at the Cu(OH)₂/STO interface that promotes enhanced charge carrier transfer and separation within the heterojunctions.