类金属WO_(2)/g-C_(3)N_(4)复合光催化剂的构造及其优异的光催化性能  

Metallic WO_(2)‐decorated g‐C_(3)N_(4)nanosheets as noble‐metal‐free photocatalysts for efficient photocatalysis

作　　者：李宁 高雪云[2] 苏俊珲 高旸钦 戈磊 Ning Li;Xueyun Gao;Junhui Su;Yangqin Gao;Lei Ge(State Key Laboratory of Heavy Oil Processing,China University of Petroleum Beijing,Beijing 102249,China;Department of Materials Science and Engineering,College of New energy and Material,China University of Petroleum Beijing,Beijing 102249,China)

机构地区：[1]中国石油大学(北京)重质油加工国家重点实验室,北京102249 [2]中国石油大学(北京)新能源与材料学院,材料科学与工程系,北京102249

出　　处：《Chinese Journal of Catalysis》2023年第4期161-170,共10页催化学报（英文）

基　　金：中国石油大学(北京)科学基金(2462017YJRC048,2462018BJC005);国家自然科学基金(51802351).

摘　　要：随着化石燃料快速消耗和环境污染日益严峻,高效光催化产氢技术作为最有前景的绿色能源技术之一而备受关注.作为典型的2D纳米片,g-C_(3)N_(4)具有很多适合应用在光催化领域的特性,如可见光效应、大比表面积和环境友好等,但单一g-C_(3)N_(4)的载流子复合率高,光催化性能不佳.研究者尝试负载贵金属(如Pt,Ag,Au等),利用贵金属功函数较高,可以快速捕获g-C_(3)N_(4)表面的光生电子,从而有效抑制光生载流子的复合;但其成本较高,限制了该技术的产业化.目前类金属材料(MoO_(2),NbO_(2),WO_(2)等)不仅表现出类似贵金属的特性,且价格低廉,有望替代贵金属.因此,引入类金属助催化剂是实现高载流子浓度和宽光谱照射下强光子吸收的好方法.本文设计并制备了类金属WO_(2)/g-C_(3)N_(4)纳米复合物,其表现出了较好的光催化性能:在可见光照射2h,4 wt%WO_(2)/g-C_(3)N_(4)的光催化降解效率高达96%;同时,4 wt%WO_(2)/g-C_(3)N_(4)/Pt产氢效率高达2436.9μmolg^(-1)h^(-1),是未改性样品3 wt%Pt/g-C_(3)N_(4)的2.55倍和非贵金属样品WO_(2)/g-C_(3)N_(4)的6.18倍,且表现出很好的循环稳定性.紫外可见漫反射光谱和态密度计算结果表明,WO_(2)具有非常窄的带隙,可吸收200-800 nm的宽范围可见光.实验测试和理论计算结果表明,WO_(2)因带隙较窄而表现出类金属特性,即在WO_(2)/g-C_(3)N_(4)界面,WO_(2)快速捕获电子,从而抑制光生载流子的复合.类金属WO_(2)因具有较低的功函数而表现出比贵金属Pt低的捕获光生电子活性.综上,本文为合理设计助催化剂/半导体,实现高效的光催化性能提供了新视角.The introduction of a metallic cocatalyst is a good strategy for achieving a high carrier density and absorbing photons under wide‐spectrum illumination.Herein,metallic WO_(2)/g‐C_(3)N_(4)nanocomposites were designed and synthesized for the first time using a simple calcination method to enhance the photocatalytic performance.WO_(2)/g‐C_(3)N_(4)exhibited significant photocatalytic properties:under visible light irradiation,4 wt%WO_(2)/g‐C_(3)N_(4)exhibited an RhB photocatalytic degradation of 96%in 120 min.Meanwhile,the H_(2)production rate of 4 wt%WO_(2)/g‐C_(3)N_(4)/3 wt%Pt was 2436.9μmol g^(-1)h^(-1),which was 2.55 and 6.18 times higher than that of 3 wt%Pt/g‐C_(3)N_(4)(956.35μmol g^(-1)h^(-1))and WO_(2)/g‐C_(3)N_(4),respectively.Experimental tests and density functional theory calculations reveal that WO_(2)exhibits a metal‐like performance with a narrow bandgap to capture electrons and hinders the recombination of photogenerated charge carriers at the interface of WO_(2)/g‐C_(3)N_(4).Our study provides a new perspective for the rational design of metallic cocatalysts/semiconductors with highly efficient photocatalytic properties.

关 键 词：g-C_(3)N_(4) 类金属WO_(2) 光催化产氢性能 光催化降解 非贵金属光催化剂 

分 类 号：TQ116.2[化学工程—无机化工] O643.36[理学—物理化学] O644.1[理学—化学]