文献类型：期刊文献

英文题名：Boosting CO production from visible-light CO2 photoreduction via defects-induced electronic-structure tuning and reaction-energy optimization on ultrathin carbon nitride

作者：Li, Jiaying[1,2];He, Chengxuan[1,2];Wang, Jinlong[1,2];Gu, Xiaoyi[1,2];Zhang, Zehan[1,2];Li, Huizi[1,2];Li, Mingyang[1,2];Wang, Lingzhi[1,2];Wu, Shiqun[1,2];Zhang, Jinlong[1,2]

机构：[1]East China Univ Sci & Technol, Key Lab Adv Mat, Joint Int Res Lab Precis Chem & Mol Engn, Feringa Nobel Prize Scientist Joint Res Ctr,Sch Ch, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Shanghai Engn Res Ctr Multimedia Environm Catalysi, Shanghai 200237, Peoples R China

年份：2023

卷号：25

期号：21

起止页码：8826

外文期刊名：GREEN CHEMISTRY

收录：;EI(收录号：20234314942063);WOS:【SCI-EXPANDED(收录号:WOS:001081003000001)】；

基金：This work was supported by National Key Research and Development Program of China (2022YFE0107900, 2022YFB3803600), the National Natural Science Foundation of China (21972040, 22202070), the Innovation Program of Shanghai Municipal Education Commission (2021-01-07-00-02-E00106), the Science and Technology Commission of Shanghai Municipality (22230780200, 20DZ2250400), the Postdoctoral Innovative Talent Support Program (BX20220107), China Postdoctoral Science Foundation (2022M720050), and the Shanghai Rising-Star Program (22YF1410200), and Fundamental Research Funds for the Central Universities (222201717003). Thanks to the Research Center of Analysis and Test of East China University of Science and Technology for the help on the characterizations.

语种：英文

外文关键词：Carbon nitride - Chemical activation - Design for testability - Electronic structure - Fourier transform infrared spectroscopy - Light absorption - Oxygen - Oxygen vacancies - Thermodynamics - Urea

摘要：Polymeric carbon nitride is a promising photocatalyst for CO2 reduction; however, its efficiency is limited by the rapid recombination of photogenerated charges and weak CO2 activation ability. In this study, we present the synthesis of g-C3N4 with carbon vacancy and oxygen doping (Vc-OCN) through a facile formaldehyde-assisted thermal polycondensation of molten urea. Comprehensive investigations were carried out and established that the oxygen doping site substituted the 2-coordinated nitrogen site while a carbon vacancy (Vc) was formed at the position of C-3N in the heptazine structure. The incorporation of Vc and oxygen doping could efficiently modify the band structure and electronic structure, leading to enhanced optical absorption and charge separation. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and DFT calculations demonstrated that the Vc-OCN reduced the energy of the rate-determining step of CO2 conversion, with the Vc serving as the active site for CO2 activation. Combining thermodynamics and kinetics optimization, Vc-OCN achieved a high CO generation rate of 13.7 mu mol g(-1) h(-1) under visible-light irradiation without the help of any cocatalysts or sacrificial agents, displaying a 7.6-fold improvement over GCN. This study provides a deep understanding of the synergistic effect of doping and vacancies on CO2 photoreduction and provides novel insights into the design of high-efficiency polymer semiconductors obtained through defects engineering.