One step hydrothermal preparation of leaf-like CuInS2 micro-nano structures on three-dimensional flexible substrate to enhance photothermal catalytic activity

One potential sustainable energy conversion technique is the photocatalytic reduction of CO2 by semiconductors. However, insufficient active sites and low utilization efficiency of solar energy lead to the unsatisfactory effect of photothermal catalytic reduction of CO2. Thus, in this study, leaf-like CuInS2 micro-nano structures are prepared on three-dimensional flexible substrate by one-step hydrothermal method to improve the photothermal CO2 reduction efficiency. Among them, the preparation process of hydrothermal method is simple, energy-saving and efficient. In addition, micro-nano structures can not only provide more active sites for photocatalysts due to their large specific surface area, but also form more pores that can promote electron transfer efficiency. Meanwhile, the introduction of sulfur vacancy can promote the separation of photogenerated carriers and improve the adsorption capacity of CO2. As a result, the yields of CO2 reduction to CO and CH4 by leaf-like CuInS2 micro-nano structures were 1285.2 μmol/m2/h and 231.4 μmol/m2/h, respectively, under the synergistic action of photothermal. At present, there are few reports about the preparation of CuInS2 micro-nano structures in flexible stainless steel mesh, which also provides a new idea for the design of efficient photothermal cocatalysts.