Photocatalytic\nMethanol Dehydrogenation Promoted Synergistically\nby Atomically Dispersed Pd and Clustered Pd

Supported\nmetal in the form of single atoms, clusters, and particles\ncan individually or jointly affect the activity of supported heterogeneous\ncatalysts. While the individual contribution of the supported metal\nto the overall activity of supported photocatalysts has been identified,\nthe joint activity of mixed metal species is overlooked because of\ntheir different photoelectric properties. Here, atomically dispersed\nPd (Pd<sub>1</sub>) and Pd clusters are loaded onto CdS, serving as\noxidation and reduction sites for methanol dehydrogenation. The Pd<sub>1</sub> substitutes Cd<sup>2+</sup>, forming hole-trapping states\nfor methanol oxidation and assisting the dispersion of photodeposited\nPd clusters. Therefore, methanol dehydrogenation on CdS with supported\nPd<sub>1</sub> and Pd clusters exhibits the highest turnover frequency\nof 1.14 s<sup>–1</sup> based on the Pd content and affords\nH<sub>2</sub> and HCHO with a similar apparent quantum yield of 87\n± 1% at 452 nm under optimized reaction conditions. This work\nhighlights the synergistic catalysis of supported metal for improved\nphotocatalytic activity.