Photoenergy-related techniques have undergone dramatic development in the past few decades. The discovery of unique properties of many nanostructures of photoenergy materials and their surfaces has led to many exciting advancements in the field of catalysis. As an important branch of catalysis, photocatalysis is an important type of catalytic reaction that is able to convert and store photo/solar energy through reactions involving electron transfer. Thus far, a large number of nano-systems have been proven effective in photocatalytic reactions due to an ideal bandgap of the material’s structure, acting as a milestone for future studies. One notable example is graphitic carbon nitride (g-C3N4), which has shown promising photocatalytic activity for water splitting due to its tunable electronic structure, ideal bandgap, flexibility for doping and defect formation, and the presence of highly active sites. There is no doubt that promising materials like g-C3N4 will continuously help in addressing the current worldwide energy issue.

However, the study of photocatalysis is also a considerable challenge due to the highly complicated reaction network, the variety of reaction selectivity, and the puzzling reaction mechanisms. Although there are thousands of studies published with promising photocatalytic materials, the reaction mechanisms are still ambiguous. Meanwhile, the rational design and screening of photocatalytic materials are a great challenge due to the expensive computational costs and the lack of effective reaction descriptors. All of these challenges are urgent and should be addressed by future studies.

The aim of this Special Issue is to collate state-of-the-art studies and discussions in photocatalytic nanomaterials for energy conversion and storage. Original research, as well as review articles, are welcomed.

Potential topics include but are not limited to the following:

• Effective photocatalysts for industrially important reactions
• Rational design and understanding of photocatalysts
• New insights into the photocatalytic reactions at the surface of nanomaterials
• Theoretical and computational study on catalyst design and mechanistic understanding
• Mechanistic studies on energy storage in nanomaterials
• Machine learning-assisted studies on photocatalytic materials