{"title":"Modulating NH2 Lewis Basicity in CTF-NH2 through Donor-Acceptor Groups for Optimizing Photocatalytic Water Splitting","authors":"Zhao Lu , Hu Lv , Qinzhuang Liu , Zhongliao Wang","doi":"10.3866/PKU.WHXB202405005","DOIUrl":null,"url":null,"abstract":"<div><div>Photocatalytic water splitting (PWS) provides an optimal approach for the sustainable production of green hydrogen. NH<sub>2</sub>-modified covalent triazine frameworks (CTFs-NH<sub>2</sub>) hold potential in PWS due to robust light uptake, optimal charge separation, and considerable redox potential. However, the high surface reaction barriers hinder the efficiency of PWS owing to the conversion difficulty of intermediate products. Modulating the Lewis basicity of NH<sub>2</sub> on CTFs offers a feasible route for addressing this challenge. In this work, electron-donating ethyl (C<sub>2</sub>H<sub>5</sub>) and electron-withdrawing 5-fluoroethyl groups (C<sub>2</sub>F<sub>5</sub>) are introduced at the <em>para</em> position of amine groups, producing C<sub>2</sub>H<sub>5</sub>-CTF-NH<sub>2</sub> and C<sub>2</sub>F<sub>5</sub>-CTF-NH<sub>2</sub>, to adjust the Lewis basicity of CTF-NH<sub>2</sub>. Through DFT calculations, the optical properties, excited states, electronic structures, dipole moments, and surface reaction processes of the CTF-NH<sub>2</sub>, C<sub>2</sub>H<sub>5</sub>-CTF-NH<sub>2</sub> and C<sub>2</sub>F<sub>5</sub>-CTF-NH<sub>2</sub> are simulated. The results indicate that the electron-withdrawing C<sub>2</sub>F<sub>5</sub> group can decrease the electron density and Lewis basicity on NH<sub>2</sub>, thereby lowering the energy barriers for hydrogen and oxygen evolution reactions, effectively ameliorating the PWS efficiency of CTF-NH<sub>2</sub>. This work unveils an innovative approach for donor-acceptor-regulated CTFs for the application of PWS.</div><div><span><figure><span><img><ol><li><span><span>Download: <span>Download high-res image (76KB)</span></span></span></li><li><span><span>Download: <span>Download full-size image</span></span></span></li></ol></span></figure></span></div></div>","PeriodicalId":6964,"journal":{"name":"物理化学学报","volume":"40 12","pages":"Article 2405005"},"PeriodicalIF":10.8000,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"物理化学学报","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1000681824001851","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Photocatalytic water splitting (PWS) provides an optimal approach for the sustainable production of green hydrogen. NH2-modified covalent triazine frameworks (CTFs-NH2) hold potential in PWS due to robust light uptake, optimal charge separation, and considerable redox potential. However, the high surface reaction barriers hinder the efficiency of PWS owing to the conversion difficulty of intermediate products. Modulating the Lewis basicity of NH2 on CTFs offers a feasible route for addressing this challenge. In this work, electron-donating ethyl (C2H5) and electron-withdrawing 5-fluoroethyl groups (C2F5) are introduced at the para position of amine groups, producing C2H5-CTF-NH2 and C2F5-CTF-NH2, to adjust the Lewis basicity of CTF-NH2. Through DFT calculations, the optical properties, excited states, electronic structures, dipole moments, and surface reaction processes of the CTF-NH2, C2H5-CTF-NH2 and C2F5-CTF-NH2 are simulated. The results indicate that the electron-withdrawing C2F5 group can decrease the electron density and Lewis basicity on NH2, thereby lowering the energy barriers for hydrogen and oxygen evolution reactions, effectively ameliorating the PWS efficiency of CTF-NH2. This work unveils an innovative approach for donor-acceptor-regulated CTFs for the application of PWS.