窄带隙/氧化物微观异质结半导体构建与光催化产氢研究

In this work, we aim to fabricate a narrow-band gap/oxide heterogeneous microjunction semicondutors with high electron driven power and study on it application on co-catalyst free photocatalytic hydrogen production. Firstly, precursor route, hrdrothermal or solvothermal methods are used to design and fabrication of oxides A, such as some of titanates and vanadates which with negative conduct band and micro-nano hierachical morphologies. Then, A is used as host material to selective epitaxial growth of guest material B in the specifically microscale surface of A to form well coupling and stable microjunctions. Material B possesses positive conduct band and narrow band gap, such as CdS, g-C3N4. The microjunctions formed by A and B, as well as the huge electric potential difference between the conduct band of A and B, are favorable to electron transport and charge separation, which play the similar effect as the co-catalyst of Pt in photocatalytic hydrogen production. The special possesses of bifunctional effect the same as that of catalyst/ co-catalyst. The changes of electronic structure, band gap structure, electronic spectral features and the promoter action for charge separation are studied by theoretical arithmetic, surface photovoltage spectroscopy and transient absorption spectroscopy. The relationship between material structure and property are revealed, in order to explore the basic principles of co-catalyst free photocatalytic hydrogen generation of semiconductor photocatalysts, to accelerate the practical process of co-catalyst free photocatalytic hydrogen generation in future.

本项目拟构筑具有高电荷驱动力的窄带隙/氧化物微观异质结半导体及无助催化剂光催化产氢性能研究。采用前驱体路线、水热、溶剂热等方法，设计合成具有分级结构的低导带位置氧化物A（如钛酸盐、钒酸盐等）。以A为主体材料，利用其微纳分级结构及选择性晶面裸露等特点，在微观尺度上调控具有高导带位置的窄带隙半导体客体材料B（如CdS, g-C3N4等）在A表面特定区域的选择性外延生长，形成有效耦合的稳定异质结。主客体材料A与B之间形成的微观异质结以及两者导带间构成的大电势差有利于光生电子的传输与电荷的分离，起到类铂的助催化效果，使异质结复合体同时具有光催化和助催化的双功能性。理论计算与稳态、瞬态光伏技术相结合，研究异质结复合体的电子结构、能带变化以及对电荷的分离促进作用，揭示材料结构与性能的关系，进一步探索无助催化剂半导体材料光催化产氢的基本原理，以加快无助催化剂光催化产氢的实用化进程。

本项目申请提出设计构筑能带结构匹配、大电荷驱动力、宽光谱响应的窄带隙/氧化物微观异质结半导体，用于无助催化剂参与的光催化产氢性能研究。在项目的支持下，主要开展了利用基团相互作用设计制备特殊结构低导带位置氧化物主体材料，原位锚定生长策略可控制备高效微观异质结和表面锚定组装策略设计制备碳基微观异质结等三方面的研究工作，发展了小分子“混凝土效应”策略、超分子前躯体路线等成功实现了高活性、特殊结构、低导带位置半导体主体材料的可控制备。进而提出了表面同素锚定的两步原位生长法和锚定组装等合成策略，成功实现了匹配的异质组分在主体材料表面特定区域的可控生长，构筑了具有接触紧密、电子传输优良的微观异质结界面的复合体催化剂材料，这些材料表现出优异的光催化产氢性能。同时也拓展了微观异质结在电催化分解水和能源转化领域的应用，表现出高效的催化性能。本项目研究为制备高性能异质结光（电）催化材料提供了理论和实验依据。在本项目的支持下，共发表SCI收录国际期刊论文82篇。授权发明专利14项。