构建K_(3)PW_(12)O_(40)/CdS核壳S型异质结实现同步太阳能光催化分解水和选择性苯甲醇氧化反应  

Hollow dodecahedron K_(3)PW_(12)O_(40)/CdS core‐shell S‐scheme heterojunction for photocatalytic synergistic H_(2)evolution and benzyl alcohol oxidation

作　　者：孙丽娟 于晓慧 唐丽永[1] 王伟康 刘芹芹[1] Lijuan Sun;Xiaohui Yu;Liyong Tang;Weikang Wang;Qinqin Liu(School of Materials Science and Engineering,Jiangsu University,Zhenjiang 212013,Jiangsu,China;School of Mechanical Engineering,Jiangsu University,Zhenjiang 212013,Jiangsu,China)

机构地区：[1]江苏大学材料科学与工程学院,江苏镇江212013 [2]江苏大学机械工程学院,江苏镇江212013

出　　处：《Chinese Journal of Catalysis》2023年第9期164-175,共12页催化学报（英文）

基　　金：国家自然科学基金(21972058);江苏省研究生科研创新计划(KYCX23_3710).

摘　　要：太阳能向化学能转化是能源催化研究领域中一项意义重大且具有挑战性的课题,实现由半导体光催化剂产生的电子和空穴同步高效利用是该领域的研究目标.在众多催化剂中,S型异质结具有高氧化还原能力和快速电荷分离能力,非常适合用于完成同步的光解水反应和有机氧化反应,使电子和空穴得到同步高效利用.苯甲醇(BA)氧化是一种典型的有机氧化反应,BA可被选择性氧化为苯甲醛(BAD),其在合成药物、维生素、香料和其他有价值的化学品等方面具有重要作用.本文采用水热法合成了keggin型多金属氧化物H3PW12O40空心十二面体(KPW),将15 nm的Cd S纳米颗粒原位集成在KPW壳体上,形成KPW@CdSS型核-壳异质结.由于CdS和KPW之间的紧密界面和费米能级差异,形成了一个巨大的内部电场(IEF),促使载流子形成S型电荷转移机制.采用能带结构分析(原位辐照X射线光电子能谱(ISI-XPS)、价带X射线光电子能谱(VB-XPS)和电子自旋共振(ESR))等方法确定了S型异质结界面上的有效电子转移途径.光照条件下原位辐照的XPS结果表明Cd、S和W元素的结合能发生了变化.与普通XPS光谱相比,Cd和S向低结合能方向移动,K,P,O和W向高结合能方向运动.原位辐照XPS结果表明,KPW@CdS所含各元素的结合能偏移,这为光催化剂中的载流子迁移和IEF的形成提供有力的证据.此外,VB-XPS和ESR结果证实电荷转移途径遵循S型机制.在光照射下,IEF作为驱动力可以促进光生载流子的分离和迁移.优化后的复合材料的析氢速率为18.7 mmol g^(-1)h^(-1),增值产物(BAD)的产率为17.5 mmolg^(-1)h^(-1),远高于Cd S.光电实验结果表明,S型异质结界面处存在强内电场效应,且复合材料的IEF强度是纯CdS的27.2倍.优化后的样品在连续照射30 h后,光催化活性没有明显下降,说明KPW@CdS异质结可以作为一种潜在的光催化剂同时生成BAD和H_(2).此外,中空结构有利于提高光�Simultaneous generation of clean energy,H_(2),and organic products holds immense potential in the realm of photocatalysis.The S-scheme heterojunction stands out for these dual-function applications due to its robust redox capacity,facilitating both the water reduction reaction and organic oxidation reactions.In this study,a Keggin-type polymetallic oxide,H3PW12O40 hollow dodecahedron(KPW),was synthesized using a hydrothermal approach.Subsequently,cadmium sulfide(CdS)nanoparticles averaging 15 nm in size were integrated in situ onto the KPW shell,resulting in the creation of a core-shell KPW@CdS S-scheme heterojunction.This optimized composite showcased a hydrogen evolution rate of 18.7 mmol g^(–1)h^(–1),alongside a value-added product,benzaldehyde,with a yield of 17.5 mmol g^(–1)h^(–1)substantially surpassing the performance of standalone CdS.This S-scheme junction,featuring a pronounced internal electronic field,emerges between the KPW and CdS.It significantly enhances the segregation of photogenerated carriers while preserving formidable redox capability.Furthermore,the hollow structure augments light absorption and utility,and the core-shell architecture delivers dual reduction and oxidation sites.As a result,the interplay between the hollow core-shell configuration and the S-scheme mode intensifies the photocatalytic activity.This research provides an innovative approach to crafting hollow S-scheme heterojunctions,aiming to optimize photocatalytic redox reactions for effective solar energy utilization.

关 键 词：S型异质结 内建电场 空心核壳结构 多金属氧酸盐 苯甲醇氧化 

分 类 号：O64[理学—物理化学]