Bridging Copper–Oxygen–Titanium Bonds for Methanol Photoreforming to Hydrogen on Zero-Dimensional/Two-Dimensional CuxO/TiO2 Heterojunctions

Solar-driven hydrogen (H2) evolution from liquid organic hydrogen carriers (LOHCs) by using rationally designed heterojunctions represents a transformative approach toward carbon neutrality. However, practical implementation is hindered by inefficient charge separation and transport, predominantly due to suboptimal interfacial engineering in conventional heterostructures. Here, dense Cu–O–Ti bonds are created between zero-dimensional (0D) CuxO nanocrystals (2–3 nm) and two-dimensional (2D) TiO2 architectures via a mechanism mediated by unsaturated oxygen atoms, which serve as electron mobility highways to ease excited-state relaxation and recombination. The optimized heterostructure achieves a record-high H2 evolution activity (64 mmol·g–1·h–1) from methanol photoreforming, outperforming pristine TiO2 and commercial TiO2 by 9-fold and 428-fold, respectively. Dynamic Cu2+/Cu+ redox cycling not only contributes to durability in extracting protons from methanol to H2 but also activates water molecules, promoting methanol oxidation into formic acid. This work points to a feasible path to overcome the quantum mechanical barriers for methanol photoreforming, powering an efficiency leap for solar-to-H2 conversion.