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

Solar-driven hydrogen (H 2 ) 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) Cu x O nanocrystals (2–3 nm) and two-dimensional (2D) TiO 2 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 H 2 evolution activity (64 mmol·g –1 ·h –1 ) from methanol photoreforming, outperforming pristine TiO 2 and commercial TiO 2 by 9-fold and 428-fold, respectively. Dynamic Cu 2+ /Cu + redox cycling not only contributes to durability in extracting protons from methanol to H 2 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-H 2 conversion.