TiO/CuO Heterojunction with Ultrafine CuO 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 TiO/CuO 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 TiO/CuO heterojunction demonstrated a notable increase of over 280 times in photocatalytic hydrogen (H) production under sunlight compared to neat TiO (8.51 mmol h g vs. 0.03 mmol h g), 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 N 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 CuO species (<2 nm) on the TiO 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 H generation by demonstrating the potential of a straightforward, low-temperature, capping or stabilizing agent-free, and environmentally benign synthesis protocol to prepare a TiO/CuO heterojunction as an efficient catalyst for sustainable H photoproduction.