CO <sub>2</sub> Photoreduction by H <sub>2</sub> O: Cooperative Catalysis of Palladium Species on Poly(triazine imide) Crystals
Xinyu Xu, Bo Su, Sibo Wang, Wandong Xing, Sung‐Fu Hung, Zhiming Pan, Yuanxing Fang, Guigang Zhang, Huabin Zhang, Xinchen Wang
Abstract
Abstract Photocatalytic CO 2 reduction coupled with H 2 O oxidation has been pursued extensively, albeit facing challenges in efficiency and selectivity. Herein, we develop a Pd SAs+NPs /PTI catalyst by co‐anchoring atomic and nanoparticulate Pd species on poly(triazine imide) crystals, which exhibits high activity, selectivity, and stability for CO 2 reduction to CO using H 2 O as the reductant. Combined experimental and theoretical studies reveal that the dual Pd species synergistically enhance charge separation and transfer while promoting CO 2 activation, CO desorption, and H 2 O dissociation. Photo‐stimulated electrons migrate to Pd nanoparticles to reduce CO 2 , and holes oxidize Pd 2+ sites to Pd 4+ species that catalyze H 2 O splitting to OH* and H*. The resulting H* spills onto adjacent Pd nanoparticles to support proton‐coupled CO 2 reduction, whereas OH* is oxidized by Pd 4+ to evolve O 2 , regenerating Pd 2+ , and closing the catalysis cycle. Importantly, the photoinduced Pd 4+ sites dynamically modulate the local adsorption environment, weakening *CO binding on nearby Pd nanoparticles. This facilitates *CO desorption and hampers its hydrogenation to CH 4 , enabling high CO selectivity. The optimal catalyst achieves a CO yield rate of 22.2 mmol g Pd −1 h −1 with 95.7% selectivity, stably operating over 30 h.