TiO2/Cu2O Heterojunction with Ultrafine Cu2O Dispersion and Enhanced Performance for Solar-Driven Hydrogen Production: A Low-Temperature, Ambient Pressure, and Common Stabilizing Agent-Free Synthesis Approach

The development of efficient catalysts for hydrogen photoproduction is a significant research field, as the demand for clean energy increases. In this context, we have successfully applied an innovative synthesis protocol for TiO2/Cu2O heterojunctions, designed to be carried out at low temperature and ambient pressure without the need for addition of a special stabilizing agent, offering a novel and efficient approach to fabricating these materials. The TiO2/Cu2O heterojunction demonstrated a notable increase of over 280 times in photocatalytic hydrogen (H2) production under sunlight compared to neat TiO2 (8.51 mmol h–1 g–1 vs. 0.03 mmol h–1 g–1), maintaining reasonable photostability, with ∼15% reduction in activity after the fifth cycle. Furthermore, the material was characterized by XRPD, scanning electron microscopy (SEM), transmission electron microscopy (TEM), DRS, EIS, and N2 physisorption. Interestingly, TEM analysis revealed that the applied synthesis protocol─despite not employing any specific capping or stabilizing agent─successfully achieved an excellent dispersion of ultrasmall Cu2O species (<2 nm) on the TiO2 support. This remarkable dispersion is responsible for the efficiency of the heterojunction interface and provides a key explanation for the outstanding photocatalytic performance observed. The present study represents a step forward in developing photocatalysts for H2 generation by demonstrating the potential of a straightforward, low-temperature, capping or stabilizing agent-free, and environmentally benign synthesis protocol to prepare a TiO2/Cu2O heterojunction as an efficient catalyst for sustainable H2 photoproduction.