Molten Salt‐Assisted Facet Control of Metal Compounds for Photocatalysis

Abstract Metal compounds have attracted considerable attention for widespread applications due to their unique electronic structures, abundant active sites, and excellent chemical stability. Facet control of metal compounds in a well‐defined manner is an efficient approach to further enhance their application performances, especially toward photocatalysis, benefiting from the optimized electronic structures of specific exposed facets, which could restrict the recombination and promote the transfer of photoinduced carriers. Owing to the accelerated atom diffusion, wide range reaction temperature, and the selective adsorption of ions on the specific facets, the molten salt‐assisted method has been widely explored to rationally regulate the exposed facets of metal compounds. In this review, the aim is to systematically summarize recent progress in the molten salt‐assisted facet control of diverse metal compounds, including metal oxides, metal nitrides, metal carbides, etc., particularly focusing on the underlying facet control mechanisms and their promising photocatalytic applications. Finally, the remaining key challenges are also outlined, and some personal perspectives in this promising research field are provided.