WO_(3)/Zn_(0.5)Cd_(0.5)S S型异质结光催化产氢耦合有机物转化机理研究  

Insights into Photocatalytic Mechanism of H2 Production Integrated with Organic Transformation over WO_(3)/Zn_(0.5)Cd_(0.5)S S-Scheme Heterojunction

作　　者：曹爽 钟博 别传彪 程蓓[1] 徐飞燕 Shuang Cao;Bo Zhong;Chuanbiao Bie;Bei Cheng;Feiyan Xu(State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology,Wuhan 430070,China;Laboratory of Solar Fuel,Faculty of Materials Science and Chemistry,China University of Geosciences,Wuhan 430078,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,武汉430070 [2]中国地质大学(武汉),材料与化学学院太阳燃料实验室,武汉430078

出　　处：《物理化学学报》2024年第5期50-54,共5页Acta Physico-Chimica Sinica

基　　金：国家重点研究与发展计划(2022YFB3803600,2022YFE0115900);国家自然科学基金(52003213,22238009,22261142666,52073223,22278324,51932007);湖北省自然科学基金(2022CFA001)资助。

摘　　要：开发新型纳米材料实现光催化产氢耦合有机物转化、提高太阳能到化学能的转换效率,在解决能源和环境危机方面具有巨大潜力。三元金属硫化物具有可调控的带隙和优异的可见光响应,在光催化分解水产氢方面引起了广泛关注。其中,Zn_(0.5)Cd_(0.5)S是一种带隙较窄、导带位置较高、耐光腐蚀的还原型光催化剂;然而,单一Zn_(0.5)Cd_(0.5)S中光生电子和空穴的复合率较高,只有少部分光生载流子参与光催化反应,导致量子效率较低而无法达到实际需求。WO_(3)是一种典型的氧化型光催化剂,具有较低的价带位置和较强的氧化能力,是与Zn_(0.5)Cd_(0.5)S耦合构建S型异质结的理想半导体。基于此,本文通过静电纺丝和水热方法将Zn_(0.5)Cd_(0.5)S纳米片垂直生长在WO_(3)纳米纤维上,制备了具有核壳结构的WO_(3)/Zn_(0.5)Cd_(0.5)S异质结。功函数的差异驱动Zn_(0.5)Cd_(0.5)S的电子转移到WO_(3)上,在界面处形成内建电场并使能带弯曲。通过原位光照X射线光电子能谱、电子顺磁共振和时间分辨荧光光谱分析,发现在内建电场、弯曲能带和库仑吸引力的作用下,WO_(3)导带上的光生电子迁移到Zn_(0.5)Cd_(0.5)S价带上并与其光生空穴复合,表明WO_(3)和Zn_(0.5)Cd_(0.5)S之间形成了S型异质结,实现了具有强氧化还原能力的载流子的高效分离。得益于独特的S型光催化机制以及反应物在催化剂表面的有效吸附与活化,没有贵金属助催化剂的情况下,WO_(3)/Zn_(0.5)Cd_(0.5)S异质结在产氢(715 μmol·g^(-1)·h^(-1))和乳酸转化为丙酮酸方面表现出增强的光催化活性,实现了光生电子和空穴的高效利用。原位漫反射傅里叶变换红外光谱和密度泛函理论计算揭示了光催化产氢和有机物转化的反应机理。本工作为设计和研究新型S型异质结光催化剂、实现高效产氢耦合有机物转化提供了新的见解。Developing novel nanostructures to enhance the efficiency of solar-tochemical conversion through integrated photocatalytic hydrogen(H2)evolution and organic transformation holds great promise in addressing pressing energy and environmental crises.Ternary metal sulfides have garnered considerable attention in photocatalytic H_(2) production due to their tunable bandgap and excellent visible light response.Among them,Zn_(0.5)Cd_(0.5)S stands out as a reduction photocatalyst with a narrow bandgap,a high conduction band level,and excellent resistance to photocorrosion.However,unitary Zn_(0.5)Cd_(0.5)S suffers from a high recombination rate of photogenerated electron/hole pairs,resulting in only a small fraction of charge carriers being involved in the photoreactions,leading to a low quantum efficiency that falls short of practical demand.WO_(3),a typical oxidation photocatalyst with a lower valence band position and strong oxidization ability,is an ideal candidate for constructing an S-scheme heterojunction with Zn_(0.5)Cd_(0.5)S.Herein,a core-shell structured WO_(3)/Zn_(0.5)Cd_(0.5)S heterojunction with Zn_(0.5)Cd_(0.5)S nanosheets vertically growing out of WO_(3) nanofibers is fabricated through electrospinning and hydrothermal methods.The distinct disparity in work functions leads to the transfer of electrons from Zn_(0.5)Cd_(0.5)S to WO_(3) upon contact,creating an interfacial electric field(IEF)and simultaneously bending the energy bands at the interface.As a consequence of IEF,bent energy bands,and coulomb attraction,the photogenerated electrons in the conduction band of WO_(3) migrate to the valence band of Zn_(0.5)Cd_(0.5)S and recombine with its photoinduced holes,signifying the formation of an S-scheme heterojunction between WO_(3) and Zn_(0.5)Cd_(0.5)S and enabling efficient separation of powerful charge carriers,as evidenced by in situ irradiated X-ray photoelectron spectroscopy,electron paramagnetic resonance,and time-resolved fluorescence spectroscopy analyses.Benefiting from the unique S-scheme photoca

关 键 词：三氧化钨 S型异质结 产氢 有机物转化 化学吸附与活化 

分 类 号：O643[理学—物理化学]