Conventional semiconductor photocatalysis based on band-edge absorption remains inefficient due to the limited harvesting of solar irradiation and the complicated surface/interface chemistry. In recent years, the photothermal catalysis derived from the localized surface plasmon resonance of noble metal nanoparticles was testified to be a promising candidate for the conversion of solar energy to chemical energy. However, this approach still has its limitations, such as low economy, poor abundance, excessive surface dependence, and narrow absorption band of light. Herein, we develop a versatile strategy to accelerate the chemical reactions based on the novel full-solar-spectrum heating effect of plasmonic semiconductor nanomaterials. In this report: (a) A well-designed hierarchical Cu7S4 hollow microsphere@zeolite imidazole framework-8 heterostructure is successfully synthesized with the photothermal core and catalytic shell. Experimentally, the plasmonic Cu7S4 nano-heater core shows a surface temperature increase as high as 94.0 oC within 4 min and an excellent photothermal transduction efficiency (31.1%) under a laser irradiation (1450 nm, 500 mW cm-2). (b) Significant enhancement (4.5-5.4 fold) of catalytic efficiency for a [3+3] cyclocondensation reaction is achieved in the near-infrared laser experiment compared to that of the thermal process at room temperature, among which 1.6-1.8 fold enhancement is ascribed to the localized heating effect. The wavelength-dependence and Arrhenius behavior of the reaction rate reveal that the plasmon-induced photothermal effect is responsible for the improved catalytic activity. (c) The concept of photothermal activation efficiency (PTAE) is proposed, for the first time, to describe the utilization efficiency of light energy for the activation of chemical reactions via photothermal effect. The simulated sunlight experiment exhibits the photothermal catalysis with high efficiency (PTAE = 0.07 %) and decent cyclic stability. These fundamental investigations demonstrate that the photothermal effect of plasmonic semiconductor nanomaterials provides an opportunity to enhance the reaction activity with efficient utilization of light. In our follow-up works, we have promoted the value of PTAE to 3.0 % in a copper-ceria photothermal catalyst for the preferential CO oxidation reaction, further manifesting the feasibility of the photothermal strategy.

Photothermal-enhanced catalysis in core-shell plasmonic hierarchical Cu7S4 microsphere@zeolitic imidazole framework-8

253rd National Meeting (2017)

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