Cooperative Shunt Photocatalysis of Pt Single Atoms and Nanoparticles for Efficient Methanol Conversion to Hydrogen and Formaldehyde.

Photocatalytic methanol dehydrogenation requires not only charge separation but, more critically, synchronized and rapid consumption of photogenerated electrons and holes-an unmet challenge in conventional Pt-based photocatalysts. Here we report a photocatalytic platform in which Pt single atoms (Pt SA) and Pt nanoparticles (Pt NP) are uniformly integrated on crystalline carbon nitride (CCN), denoted CCN-Pt SA+NP, via photoinduced reduction of chloroplatinic acid. In situ spectroscopic analyses reveal that spatially separated Pt SA/Pt NP redox pairs enable balanced and rapid photocarrier utilization, yielding closely matched TA-derived decay time constants of photogenerated holes and electrons of 405.1 and 386.7 ps, respectively. This synchronized charge consumption effectively suppresses recombination. Meanwhile, Pt single-atom sites enhance methanol adsorption and lower the energy barrier for the initial O─H bond cleavage, favoring the generation of alkoxy intermediates. The accelerated hole consumption and proton supply at the oxidation site further facilitate proton-electron coupling reactions on Pt nanoparticles. Consequently, the optimized CCN-Pt SA+NP catalyst delivers exceptional photocatalytic performance, achieving H2 and HCHO evolution rates of 24.5 and 22.6 mmol g-1 h-1, respectively, with an H2-to-HCHO ratio approaching unity. This work establishes a general strategy for engineering single-atom/nanoparticle redox pairs to realize matched electron-hole consumption and selective, low-carbon methanol-to-hydrogen conversion.