Efficient photoelectrochemical CO_(2) conversion for selective acetic acid production

高效光电化学催化CO_(2)转化合成乙酸

Amidst the development of photoelectrochemical(PEC)CO_(2) conversion toward practical application,the production of high-value chemicals beyond C1 compounds under mild conditions is greatly desired yet challenging.Here,through rational PEC device design by combining Au-loaded and N-doped TiO_(2) plate nanoarray photoanode with Zn-doped Cu_(2)O dark cathode,efficient conversion of CO_(2) to CH3COOH has been achieved with an outstanding Faradaic efficiency up to 58.1%(91.5%carbon selectivity)at 0.5 V vs.Ag/AgCl.Temperature programmed desorption and in situ Raman spectra reveal that the Zn-dopant in Cu_(2)O plays multiple roles in selective catalytic CO_(2) conversion,including local electronic structure manipulation and active site modification,which together promote the formation of intermediate*CH2/*CH3 for C-C coupling.Apart from that,it is also unveiled that the sufficient electron density provided by the Au-loaded and N-doped TiO_(2) plate nanoarray photoanode plays an equally important role by initiating multi-electron CO_(2) reduction.This work provides fresh insights into the PEC system design to reach the multi-electron reduction reaction and facilitate the C-C coupling reaction toward high-value multicarbon(C2+)chemical production via CO_(2) conversion.

光电化学(PEC)催化CO_(2)转化合成高附加值多碳化合物具有广阔的应用前景.本文将Au纳米晶修饰N掺杂TiO_(2)纳米片的光阳极与Zn掺杂Cu_(2)O阴极相结合,构筑了高效PECCO_(2)转化体系.该体系在较低外加偏压(0.5 V vs.Ag/AgCl)和光照条件下能够实现CO_(2)高效转化合成CH3COOH,其法拉第效率高达58.1%(碳产物的选择性为91.5%).研究人员进一步利用程序升温脱附和原位拉曼光谱发现阴极上Zn的引入能够在选择性催化CO_(2)转化合成CH3COOH过程中起到关键作用:(1)优化Cu_(2)O局部电子结构;(2)增加表面反应活性位点;(3)促进C-C偶联中间体CH2/*CH3的形成.而Au纳米晶修饰N掺杂TiO_(2)纳米片优异的光响应则能够为反应提供更多的光生电子,进而提高催化反应速率.这项工作不仅实现了高选择性光电化学催化CO_(2)向高附加值产物的转化,同时为高效PEC CO_(2)转化体系的设计提供了新的思路.