In Situ Assembled ZnWO_(4)/g-C_(3)N_(4)S-Scheme Heterojunction with Nitrogen Defect for CO_(2)Photoreduction

原位合成S型氮缺陷ZnWO_(4)/g-C_(3)N_(4)异质结及CO_(2)光还原性能

Reforming CO_(2)into storable solar fuels via semiconductor photocatalysis is considered an effective strategy to solve the greenhouse effect and resource shortage.Unfortunately,the problem of rapid photogenerated carriers severely limits the CO_(2)reduction capability of one-component catalysts.The fabrication of S-scheme heterojunctions with defects can result in efficient spatial separation of photo-generated charge carriers and increase adsorption and activation of nonpolar molecules.Herein,ZnWO_(4)/g-C_(3)N_(4)S-scheme heterojunctions with defects are constructed through in situ growth method.The experiments show that the generation rate of CO from CO_(2)reduction is up to 232.4μmol∙g^(−1)∙h^(−1)with a selectivity close to 100%,which is 11.6 and 8.5 times higher than those of pristine ZnWO_(4)and g-C_(3)N_(4),respectively.In situ XPS and work function analyses demonstrate the S-scheme charge transport pathway,which facilitates the spatial segregation of photogenerated carriers and promotes CO_(2)reduction.In situ ESR illustrates that CO_(2)molecules are adsorbed by nitrogen vacancies,which act as photoelectron acceptors during the photocatalytic reaction and are favorable for charge trapping and separation.The S-scheme charge transport mode and nitrogen vacancy work together to stimulate the efficient conversion of CO_(2)to CO.This work presents significant insights to the cooperative influence of the S-scheme charge transport mode and defects in regulating CO_(2)reduction activity.

通过半导体光催化将CO_(2)转化为可储存的太阳能燃料是解决温室效应和资源短缺问题的有效策略。然而,光生载流子的快速复合严重限制了单组分催化剂的CO_(2)还原能力。合成具有缺陷的S型异质结可以有效地分离光生电子和空穴,增强对非极性分子的吸附和活化。本文采用原位合成的方法构建了具有缺陷的S型ZnWO_(4)/g-C_(3)N_(4)异质结。结果表明,CO_(2)还原产生CO的速率高达232.4μmol·g^(-1)·h^(-1),选择性接近100%,分别是原始ZnWO_(4)和g-C_(3)N_(4)的11.6倍和8.5倍。原位XPS和功函数分析证明了S型电荷转移路径。S型异质结实现了电子-空穴的有效空间分离,促进了CO_(2)的还原。原位ESR表明CO_(2)分子被氮空位吸附,氮空位是光催化反应中的电子受体,有利于电子捕获和分离。S型电荷转移模式和氮空位共同促进了CO_(2)高效还原。这项工作为了解S型电荷转移机理和缺陷在调节CO_(2)还原活性方面的协同作用提供了重要见解。