Diatomic Palladium Catalyst for Enhanced Photocatalytic Water-Donating Transfer Hydrogenation
En Zhao, Jordi Morales‐Vidal, Yue Yang, Sharon Mitchell, Yinlong Zhu, Zhiwei Hu, Jin‐Ming Chen, Shu-Chih Haw, Ting‐Shan Chan, Ziyi Fan, Zhu‐Jun Wang, Núria López, Javier Pérez‐Ramírez, Zupeng Chen
Abstract
Diatomic catalysts (DACs) present unique opportunities for harnessing ensemble effects between adjacent metal atoms, thus, expanding the properties of single-atom catalysts (SACs). However, the precise preparation and characterization of this type of catalyst remains challenging. Following a precursor-preselected strategy, here, we report the synthesis of a carbon nitride-supported Pd-DAC, which achieves an excellent yield of 92% for photocatalytic water-donating transfer hydrogenation of 4-vinylphenol to 4-ethylphenol, far exceeding that of other metal species, including Pd single atoms (47%) and nanoparticles (1%). Combining transmission electron microscopy with standardized machine learning atom-detection methods confirms the stabilization of a substantial fraction of dimeric Pd species over carbon nitride. Density functional theory (DFT) simulations associate the outstanding performance of Pd-DAC to enhanced substrate activation in the hydrogenation path compared to Pd-SAC. The work provides criteria for DACs characterization and demonstrates a transfer hydrogenation application that is sustainable and eco-friendly over conventional hydrogenation technologies.