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Tierui Zhang1 2

1, Technical Institute of Physics and Chemistry (TIPC), Chinese Academy of Sciences (CAS), Beijing, , China
2, University of Chinese Academy of Sciences, Beijing, , China

It is still a great challenge to develop highly efficient photocatalysts for solar fuels to deal with the energy crisis and climate change. Layered double hydroxides (LDHs), are a very promising family of photocatalysts, due to their easily controllable metal cation composition and thicknesses that allow band gap tuning.1 By carefully synthesizing LDH nanosheets of a few nanometers thick, oxygen-vacancies can be easily generated on the surface/edge of LDH nanosheets, which promote the adsorption of CO2 on the surface of LDH nanosheets, thereby enhancing the rates of photocatalytic CO2 reduction to CO in the presence of water vapor.2 Furthermore, heterostructured catalysts consisting of nickel nanoparticles partially decorated with nickel oxide layers (NiOx/Ni) supported on alumina prepared based on the topological transformation of LDHs can be used to selectively synthesize hydrocarbons with chain lengths of up to seven carbon atoms at room temperature via carbon monoxide (CO) hydrogenation under mild reaction conditions in the presence of sunlight, mainly attributed to the controlled reaction path of intermediate species induced by the interfacial synergistic effect.3 A series of CoFe-based catalysts were successfully fabricated via direct H2 reduction of a CoFeAl-LDH nanosheet precursor. By varying the reduction temperature, three unique catalysts were obtained, each of which showed distinct activity and product selectivity for CO2 hydrogenation under simulated solar excitation. LDH precursor reduction at temperatures above 600 oC resulted in CoFe-alloy nanoparticle formation, thereby affording a remarkable CO2 hydrogenation selectivity towards high value (C2+) hydrocarbons through photothermal effects.4 The above results provide a full understanding of surface and interfacial at the nanoscale for achieving improved photocatalytic performance.

References
1. Y. Zhao, T. R. Zhang, et al., Adv. Energy Mater. 2016, 6 (6), 1501974.
2. Y. Zhao, T. R. Zhang, et al., Adv. Mater. 2015, 27, 7824.
3. Y. Zhao, T. R. Zhang, et al, Angew. Chem. Int. Ed. 2016, 55, 4215.
4. Y. Zhao, T. R. Zhang, et al, Adv. Mater. 2017, 55, 1703828.

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