Sulfur-mediated photodeposition synthesis of NiS cocatalyst for boosting H2-evolution performance of g-C3N4 photocatalyst  

NiS助催化剂的硫调控光沉积合成及其增强g-C3N4的光催化产氢性能

作　　者：Min Wang Jingjing Cheng Xuefei Wang Xuekun Hong Jiajie Fan Huogen Yu 王敏;程晶晶;王雪飞;洪学鹍;范佳杰;余火根(武汉理工大学化学化工与生命科学学院化学系,湖北武汉430070;常熟理工学院物理与电子工程学院,江苏常熟215500;郑州大学材料科学与工程学院,河南郑州450001;武汉理工大学硅酸盐建筑材料国家重点实验室,湖北武汉430070)

机构地区：[1]Department of Chemistry,School of Chemistry,Chemical Engineering and Life Sciences,Wuhan University of Technology,Wuhan 430070,Hubei,China [2]College of Physics and Electronic Engineering,Changshu Institute of Technology,Changshu 215500,Jiangsu,China [3]School of Materials Science and Engineering,Zhengzhou University,Zhengzhou 450001,Henan,China [4]State Key Laboratory of Silicate Materials for Architectures,Wuhan University of Technology,Wuhan 430070,Hubei,China

出　　处：《Chinese Journal of Catalysis》2021年第1期37-45,共9页催化学报（英文）

基　　金：国家自然科学基金(51672203);中央高校基本科研业务费专项基金(WUT2019IB002,185220002).

摘　　要：Modification of nickel sulfide cocatalysts is considered to be a promising approach for efficient enhancement of the photocatalytic hydrogen production performance of g-C3N4.Providing more NiS cocatalyst to function as active sites of g-C3N4 is still highly desirable.To realize this goal,in this work,a facile sulfur-mediated photodeposition approach was developed.Specifically,photogenerated electrons excited by visible light reduce the S molecules absorbed on g-C3N4 surface to S^2‒,and subsequently NiS cocatalyst is formed in situ on the g-C3N4 surface by a combination of Ni2+and S2‒due to their small solubility product constant(Ksp=3.2×10^‒19).This approach has several advantages.The NiS cocatalyst is clearly in situ deposited on the photogenerated electron transfer sites of g-C3N4,and thus provides more active sites for H2 production.In addition,this method utilizes solar energy with mild reaction conditions at room temperature.Consequently,the synthesized NiS/g-C3N4 photocatalyst achieves excellent hydrogen generation performance with the performance of the optimal sample(244μmol h^‒1 g^‒1)close to that of 1 wt%Pt/g-C3N4(316μmol h^‒1 g^‒1,a well-known excellent photocatalyst).More importantly,the present sulfur-mediated photodeposition route is versatile and facile and can be used to deposit various metal sulfides such as CoSx,CuSx and AgSx on the g-C3N4 surface,and all the resulting metal sulfide-modified g-C3N4 photocatalysts exhibit improved H2-production performance.Our study offers a novel insight for the synthesis of high-efficiency photocatalysts.作为一种非金属聚合半导体,石墨相氮化碳(g-C3N4)具有特殊的能带结构、可见光响应能力以及优良的物理化学性质以及生产成本低等特点,因而已成为目前光催化领域的研究热点.然而,由于g-C3N4被光激发的电子与空穴极易复合,导致g-C3N4材料的光催化性能并不理想.而助剂修饰是实现光生载流子有效分离以提高光催化活性的有效途径.众所周知,贵金属Pt可以作为光催化产氢的反应位点,但高昂的成本限制了它的实际应用.所以,开发高效的非贵金属助剂很有必要.近年来,NiS作为优良的电子助剂在光催化领域受到广泛关注.大量研究表明,NiS可以作为g-C3N4的产氢活性位点用于提高其光催化产氢性能.NiS助剂主要是通过水热、煅烧和液相沉淀的方法修饰在g-C3N4的表面上.相较而言,助剂的光沉积方法具有一些独特的优势,例如节能、环保、简易并且能够实现其原位牢固地沉积在光催化剂的表面.然而g-C3N4光生电子和空穴强还原和氧化能力容易导致像Ni^2+的还原和S^2-的氧化等副反应发生,因此NiS助剂很难光沉积在g-C3N4材料表面.本文采用硫调控的光沉积法成功合成了NiS/g-C3N4光催化材料,该法利用g-C3N4在光照条件下产生的光生电子结合S以及Ni^2+生成NiS,然后原位沉积在g-C3N4表面.由于E0(S/NiS)(0.096 V)比E0(Ni^2+/Ni)(-0.23 V)更正,所以NiS优先原位沉积在g-C3N4表面.因此,硫调控的光沉积法促进了NiS的生成,并抑制了金属Ni等副反应的形成.通过X射线光电子能谱分析NiS/g-C3N4的表面化学态,表明该方法能成功地将NiS修饰在g-C3N4的表面,这也得到透射电镜和高分辨透射电镜结果的证实.光催化产氢的结果表明,NiS/g-C3N4光催化剂实现了良好的光催化性能,其最优产氢速率(244μmol h^‒1 g^‒1)接近于1 wt%Pt/g-C3N4(316μmol h^‒1 g^‒1).这是因为硫调控的光沉积法实现NiS助剂在g-C3N4表面的修饰,从而促进光生�

关 键 词：g-C3N4 NIS Co-catalyst Sulfur-mediated photodeposition H2 Photocatalysis 

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]