High quantum efficiency of hydrogen production from methanol aqueous solution with PtCu-TiO2 photocatalysts

Liquid water reforming of methanol is a promising method for on-demand hydrogen production. An atomic-level catalyst design strategy, using synergy between single atoms and nanodots, is now shown to demonstrate a high quantum efficiency for hydrogen production. Methanol with 12.5 wt% H-2 content is widely considered a liquid hydrogen medium. Taking into account water with 11.1 wt% H-2 content, H-2 synthesis from the mixture of water and methanol is a promising method for on-demand hydrogen production. We demonstrate an atomic-level catalyst design strategy using the synergy between single atoms and nanodots for H-2 production. The PtCu-TiO2 sandwich photocatalyst achieves a remarkable H-2 formation rate (2,383.9 mu mol h(-1)) with a high apparent quantum efficiency (99.2%). Furthermore, the oxidation product is a high-value chemical formaldehyde with 98.6% selectivity instead of CO2, leading to a nearly zero-carbon-emission process. Detailed investigations indicate a dual role of the copper atoms: an electron acceptor to facilitate photoelectron transfer to Pt, and a hole acceptor for the selective oxidation of methanol to formaldehyde, thus avoiding over-oxidation to CO2. The synergy between Pt nanodots and Cu single atoms together reduces the activation energy of this process to 13.2 kJ mol(-1).

Automated summary

A promising method for on-demand hydrogen production is demonstrated using an atomic-level catalyst design strategy that combines single atoms and nanodots. The PtCu-TiO2 sandwich photocatalyst achieves a high formation rate of H-2 with a high quantum efficiency.