Understanding Boosted Selective CO<sub>2</sub>‐to‐CO Photoreduction with Pure Water Vapor over Hierarchical Biomass‐Derived Carbon Matrix
Zhifeng Jiang, Zhiquan Zhang, Jianli Liang, Min Zhou, Daobin Liu, Danjun Mao, Qun Zhang, Wei Zhang, Huaming Li, Li Song, Taicheng An, Po Keung Wong, Chun‐Sing Lee
Abstract
Abstract Solar‐driven CO 2 reduction reaction (CO 2 RR) with water into carbon‐neutral fuels is of great significance but remains challenging due to thermodynamic stability and kinetic inertness of CO 2 . Biomass‐derived nitrogen‐doped carbon (N‐C b ) have been considered as promising earth‐abundant photocatalysts for CO 2 RR, although their activities are not ideal and the reaction mechanism is still unclear. Herein, an efficient catalyst is developed for CO 2 ‐to‐CO conversion realized on diverse N‐C b materials with hierarchical pore structures. It is demonstrated that the CO 2 ‐to‐CO conversion preferentially takes place on positively charged carbon atoms next to pyridinic‐N using two representatives treated pollens with the largest difference in pyridinic‐N density and N content as model photocatalysts. Systematic experimental results indicate that surface local electric field originating from charge separation can be boosted by hierarchical pore structures, doped N, as well as pyridinic‐N. Mechanistic studies reveal that positively charged carbon atoms next to pyridinic‐N serve as active sites for CO 2 RR, reduce the energy barrier on the formation of CO*, and facilitate the CO 2 RR performance. All these benefits cooperatively contribute to treated chrysanthemum pollen catalyst exhibiting excellent CO formation rate of 203.2 µmol h −1 g −1 with 97.2% selectivity in pure water vapor. These results provide a new perspective into CO 2 RR on N‐C b , which shall guide the design of nature‐based photocatalysts for high‐performance solar‐fuel generation.