In2S3 Growth Templated by Aluminogermanate Double-Walled Imogolite Nanotubes Toward Efficient Visible Light Photocatalysts

Abstract

Different strategies combining semiconductors and nanomaterials have been explored to enhance the performance of visible light photocatalysts. This work reports the hydrothermal growth of In2S3 on the aluminogermanate double-walled imogolite nanotubes and the photocatalytic properties of the resulting composites. The reaction conditions are optimized to ensure the linear growth of In2S3, while preserving the tubular structure of imogolite nanotubes. The imogolite–In2S3 composites show enhanced photocatalytic degradation of methyl orange compared to the control In2S3, exhibiting a fourfold increase in the photocatalytic dye degradation rate constant. Interestingly, these composites present a negative photocurrent response, indicating the generation of mobile holes, whereas both In2S3 and imogolite by themselves exhibit typical positive photocurrent behavior. The improvement in the photocatalytic dye degradation and the negative photocurrent response is attributed to the interface formation between In2S3 and imogolite in these composites and the p-type character of the latter. Templating the colloidal synthesis of semiconducting nanoparticles in confined spaces could bring a step change in the design of catalytic and photocatalytic materials.