The research group led by Prof. Yujie Xiong made new progress on the design of hybrid photocatalysts, based on their previous findings on related topics (refer to: Angew. Chem. Int. Ed. 2014, 53, 5107; Angew. Chem. Int. Ed. 2014, 53, 3205). Teamed up with Prof. Jun Jiang and Prof.Qun Zhang, the researchers performed the studies by integrating controlled synthesis with theoretical simulations and advanced characterizations, and designed semiconductor-based hybrid structures with tunable charge transfer and molecular activation, enabling improved photocatalytic efficiency for water splitting and carbon dioxide conversion. This series of progress has been published in Advanced Materials 2014, 26, 5689 (http://onlinelibrary.wiley.com/doi/10.1002/adma.201401817/) and Advanced Materials 2014, 26, 4783 (http://onlinelibrary.wiley.com/doi/10.1002/adma.201400428/abstract), and highlighted on the inside front cover and inside back cover of Advanced Materials, respectively.
Design of hybrid photocatalysts highlighted on the inside front cover and inside back cover of Advanced Materials
It has been commonly recognized that development of functional materials is encountering a major bottleneck that bare material systems cannot meet the demand of practical applications. Given that each specific material possesses its own unique function and advantage, the integration of materials with differentiated electronic structures would be a valid approach to overcoming the limitation of bare materials. More importantly, the synergetic interplay between component materials may further enhance their overall performance (i.e., 1 + 1 > 2). Specifically in the photocatalytic system, different component units in hybrid structures can play various important roles in the complex processes such as charge separation and molecular activation. However, it is not practical to achieve the integration of component properties in most cases mainly due to the difficulty of interface control. The low quality of interface would induce severe charge recombination, largely wasting solar energy.
To address this grand challenge, the researchers have designed a series of hybrid structures with controllable interfaces. For example, they proposed a novel semiconductor-metal-graphene stack design whose single-crystal interface can substantially reduce interfacial charge recombination and thus better harness the Schottky barrier between semiconductor and metal to improve charge separation. This structure exhibits significantly enhanced performance in photocatalytic hydrogen production (Advanced Materials 2014, 26, 5689). In another case, they designed metal-organic framework (MOF)-semiconductor core-shell structures to solve the problem that gas molecules can be hardly captured in photocatalytic gaseous reactions. In this design, the photoexcited electrons in semiconductor are efficiently delivered to MOF and maintain long lifetime, while the carbon dioxide adsorbed in the MOF can be specifically converted into methane upon receiving the electrons, dramatically improving reaction activity and selectivity for carbon dioxide conversion (Advanced Materials 2014, 26, 4783). In the studies, both ultrafast spectroscopy characterizations and theoretical simulations have verified the niche of designed structures and elucidated the working mechanisms. It is anticipated that this series of works cast new light on rational design of hybrid photocatalysts, and provide new insights into charge behavior and mechanisms in hybrid functional materials.
This work was supported by 973 Program, NSFC, Recruitment Program of Global Experts, CAS Hundred Talent Program, and Fundamental Research Funds for the Central Universities.
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