Noble metal single atoms (SAs) on semiconductors are increasingly explored as co-catalysts to enhance the efficiency of photocatalytic hydrogen production. In this study, we introduce a "spontaneous deposition" approach to anchor Pd SAs onto graphitic carbon nitride (g-C3N4) using a highly dilute tetraaminepalladium(ii) chloride precursor. Maximized photocatalytic activity and significantly reduced charge transfer resistance can be achieved with a remarkably low Pd loading of 0.05 wt% using this approach. The resulting Pd SA-modified g-C3N4 demonstrates a remarkable hydrogen production efficiency of 0.24 mmol h-1 mg-1 Pd, which is >50 times larger than that of Pd nanoparticles deposited on g-C3N4 via conventional photodeposition. This significant enhancement in catalytic performance is attributed to improved electron transfer facilitated by the optimal coordination of Pd SAs within the g-C3N4 structure.

Department of Chemical Engineering University of Chemistry and Technology Technická 3 Prague 160 00 Czech Republic

Department of Materials Science WW4 LKO Friedrich Alexander University of Erlangen Nuremberg Martensstrasse 7 91058 Erlangen Germany

Institute of Catalysis Research and Technology KIT Hermann von Helmholtz Platz 1 76344 Eggenstein Leopoldshafen Germany

Laboratoire de Chimie de Coordination CNRS Université de Toulouse INPT UPR 8241 205 Route de Narbonne 31077 Toulouse Cedex 4 France

Regional Centre of Advanced Technologies and Materials Šlechtitelů 27 78371 Olomouc Czech Republic

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