School of Light Industry and Chemical Engineering, Dalian Polytechnic University, Dalian, 116034, China.
School of Light Industry and Chemical Engineering, Dalian Polytechnic University, Dalian, 116034, China.
Environ Res. 2022 Sep;212(Pt C):113390. doi: 10.1016/j.envres.2022.113390. Epub 2022 May 5.
Constructing photocatalyst with both high efficiency and selectivity is highly desired in water treatment process. However, it is difficult to realize the selectivity of photocatalysis due to the non-selective oxidative species produced in this process. Herein, for the first time, the photocatalytic selectivity was achieved on g-CN (CN) through N vacancy introduction for effective removal of organic pollutants, and the mechanism of vacancy induced selectivity enhancement was studied. The nitrogen vacancy modified CN (VCN) showed enhanced photocatalytic activity and unique selectivity towards phenolic compounds with electron-donating group, whose kinetic constant for p-aminophenol (p-NH) degradation was 5.95 times higher than that over CN. Moreover, VCN photocatalytic system also displayed similar selectivity in binary pollutant systems. Characteristics and theoretical calculation results confirmed the enhanced photocatalytic performance and selectivity of VCN was mainly attributed to the effect of N vacancy. On one hand, electron-deficient N vacancy enhanced the adsorption of the O and phenolic compounds, which promoted the production of O and strengthened the photocatalytic surface reaction. On the other hand, the N vacancy preferred to adsorb the electron-donating groups of phenolic compounds, which resulted in their selective removal.
在水处理过程中，构建高效且具有选择性的光催化剂是人们所期望的。然而，由于该过程中产生的非选择性氧化物种，光催化的选择性难以实现。在此，首次通过引入氮空位，在 g-CN（CN）上实现了光催化选择性，研究了空位诱导选择性增强的机制。具有供电子基团的酚类化合物的电子给体，其对邻氨基酚（p-NH）降解的动力学常数比 CN 高 5.95 倍。此外，VCN 光催化体系在二元污染物体系中也表现出相似的选择性。特性和理论计算结果证实，VCN 的增强的光催化性能和选择性主要归因于氮空位的影响。一方面，电子缺陷的氮空位增强了 O 和酚类化合物的吸附，促进了 O 的产生并加强了光催化表面反应。另一方面，氮空位优先吸附酚类化合物的供电子基团，导致它们被选择性去除。
