ZnCdS纳米球和二苯并噻吩修饰的g-C_(3)N_(4)构成的S型异质结用于增强光催化产氢  

S-scheme heterojunction of ZnCdS nanospheres and dibenzothiophene modified graphite carbon nitride for enhanced H_(2)production

作　　者：李瀚 陶善仁 万思杰 邱国根 龙庆 余家国[1,2] 曹少文 Han Li;Shanren Tao;Sijie Wan;Guogen Qiu;Qing Long;Jiaguo Yu;Shaowen Cao(State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology,Wuhan 430070,Hubei,China;Laboratory of Solar Fuel,Faculty of Materials Science and Chemistry,China University of Geosciences,Wuhan 430074,Hubei,China)

机构地区：[1]武汉理工大学材料复合新技术国家重点实验室,湖北武汉430070 [2]中国地质大学材料与化学学院,太阳燃料实验室,湖北武汉430074

出　　处：《Chinese Journal of Catalysis》2023年第3期167-176,共10页催化学报（英文）

基　　金：国家重点研发计划(2022YFE0114800);国家自然科学基金(51922081,51961135303,51932007);大学生创新创业训练计划(S202210497017);中央高校基本科研业务费专项资金资助(武汉理工大学:2022-CL-A1-01).

摘　　要：光催化分解水产氢被认为是一种具有应用前景的策略来应对能源和环境挑战.许多种类的光催化剂如CdS和TiO_(2)等,已被广泛研究并用于光催化制氢.在各种半导体中,g-C_(3)N_(4)因其能带结构恰当、稳定性好、无毒以及制备容易等优点成为有前途的光催化剂.然而,由于g-C_(3)N_(4)的可见光吸收较差,光激发的载流子复合严重等问题导致其光催化活性相对较低.因此,研究人员采用了纳米结构设计、掺杂、构建异质结和负载助催化剂等策略来对g-C_(3)N_(4)进行改性.通过引入合适的电子供体(D)或受体(A)单元,在g-C_(3)N_(4)基本构型内创建一个分子内D-A结构,被确认为一种有效的策略来提高光催化性能.分子内的D-A结构不仅使g-C_(3)N_(4)的带隙变窄以提高其光吸收能力,还形成了一个内建电场,加速了激子的解离、体相载流子的分离和传输.但单组分的光催化剂仍然存在可见光吸收不足和较严重的载流子复合问题.为了进一步提高光催化产氢的性能,构建梯型(S型)异质结是解决这些问题的有效方法.S型异质结通过内部电场可以实现有效的空间载流子分离,同时保留光生电子和空穴的强大的氧化还原能力.因此,寻找另外一个能带结构匹配的半导体来与g-C_(3)N_(4)构成S型异质结是非常可取的.另一方面,ZnCdS固溶体已经被广泛用于光催化产氢.在固溶体晶格中用锌原子替代镉原子,不仅可以连续调节能带结构,还可以提高其稳定性.为了充分利用固溶体和D-A结构的优势,本文通过自组装方法合成了ZCS(ZnCdS纳米球)@DBTCN(二苯并噻吩基团修饰的g-C_(3)N_(4))S型异质结光催化剂.红外光谱、高分辨透射电镜和X射线光电子能谱等结果证明形成了紧密接触的ZCS@DBTCN异质结.研究了ZCS和DBTCN的能带结构,通过开尔文探针、莫特肖特基曲线和带隙结果确定了ZCS和DBTCN的功函数,导带和价带位置.结果表明,DBTCN�g-C_(3)N_(4)-based photocatalysts with an intramolecular donor-acceptor structure still suffer from inadequate visible-light absorption and severe charge recombination.Constructing S-scheme heterojunction is a promising approach to address these issues.Herein,ZCS(ZnCdS nanospheres)@DBTCN(g-C_(3)N_(4)modified by dibenzothiophene groups)S-scheme heterojunction photocatalyst was synthesized through a self-assembly approach.The ZCS@DBTCN material showed a superior photocatalytic H_(2)production activity of 8.87 mmol g^(-1)h^(-1),which is 3.46 and 2.55 times that of pure DBTCN and ZCS,respectively.This enhanced photocatalytic performance could be ascribed to the synergistic effect of intramolecular internal electric field and S-scheme heterojunction,which boosts the separation and transport of photogenerated carriers within the molecular framework and at the interface,and preserves the maximum redox capacity of the spatially separated electrons and holes.Moreover,the S-scheme charge migrate mechanism of ZCS@DBTCN was strongly evidenced by the in-situ irradiated Kelvin probe force microscopy and in-situ irradiated X-ray photoelectron spectroscopy.This study provides a protocol for designing g-C_(3)N_(4)-based hybrid photocatalysts with high charge separation efficiency and excellent photocatalytic activity.

关 键 词：光催化 氮化碳 锌镉硫 S型异质结 电子转移 

分 类 号：O643.36[理学—物理化学]