Deng Zhiqin, Ma Chaoqun, Li Zerong, Luo Yongsong, Zhang Longcheng, Sun Shengjun, Liu Qian, Du Juan, Lu Qipeng, Zheng Baozhan, Sun Xuping
College of Chemistry, Sichuan University, Chengdu610064, Sichuan, China.
Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu610054, Sichuan, China.
ACS Appl Mater Interfaces. 2022 Oct 19;14(41):46595-46602. doi: 10.1021/acsami.2c12772. Epub 2022 Oct 5.
Electrocatalytic nitrate reduction reaction (NORR) affords a bifunctional character in the carbon-free ammonia synthesis and remission of nitrate pollution in water. Here, we fabricated the CoO nanosheet array with cobalt vacancies on carbon cloth (v-CoO/CC) by in situ etching aluminum-doped CoO/CC, which exhibits an excellent Faradaic efficiency of 97.2% and a large NH yield as high as 517.5 μmol h cm, better than the pristine CoO/CC. Theoretical calculative results imply that the cobalt vacancies can tune the local electronic environment around Co sites of CoO, increasing the charge and reducing the electron cloud density of Co sites, which is thus conducive to adsorption of NO on Co sites for greatly enhanced nitrate reduction. Furthermore, the v-CoO (311) facet presents excellent NORR activity with a low energy barrier of about 0.63 eV on a potential-determining step, which is much smaller than pristine CoO (1.3 eV).
电催化硝酸盐还原反应（NORR）在无碳合成氨和缓解水中硝酸盐污染方面具有双功能特性。在此，我们通过原位蚀刻铝掺杂的CoO/CC在碳布上制备了具有钴空位的CoO纳米片阵列（v-CoO/CC），其表现出97.2%的优异法拉第效率和高达517.5 μmol h cm的高NH产率，优于原始的CoO/CC。理论计算结果表明，钴空位可以调节CoO的Co位点周围的局部电子环境，增加Co位点的电荷并降低其电子云密度，从而有利于NO在Co位点上的吸附，大大增强硝酸盐还原。此外，v-CoO（311）晶面在电位决定步骤上具有约0.63 eV的低能垒，表现出优异的NORR活性，这比原始的CoO（1.3 eV）小得多。
