Artificial photosynthesis (AP) technology which integrates solar energy harvesting and chemical conversion process into one device is a promising solution to both global energy and environmental crises. Despite decades of research, AP for solar hydrogen production and CO2 reduction remains in the technological infancy. The low profit margins of the targeted products, the highly energy‐intensive process, and the engineering impracticality have kept AP technology in the laboratory demonstration stage. Photobiorefinery, a photocatalytic process for biomass valorization, has emerged as a new promising application for AP technology. This process offers high‐value products, requires less energy, and potentially could utilize AP process to enhance selectivity. In this Minireview, the recent progress in photocatalytic biomass depolymerization, partial oxidation, hydrogenolysis, and hydrogenation are featured. Challenges and prospects of the photocatalytic biomass valorization towards commercialization are also discussed.

Although single-atom catalysts (SACs) show significantly higher catalytic performance compared to conventional and nanoparticle-based catalysts (NPs) at the same amount of metal loading, their overall catalytic performance may still be unable to compete with the NPs in many applications due to the limited active sites. Generally, trace amounts of metal (less than 1 wt%) can be successfully loaded onto supports in an atomically-dispersed feature, and higher metal loading usually results in aggregation of the metal atoms. Hence, it is very important to further increase the density of isolated metal atoms in these rising-star SACs to pave the ways for widespread applications or even to replace the NPs. On the other hand, it is well known that this is one of the most challenging topics on SACs research. In this review, the advanced strategies to overcome this challenge and achieve high loading of isolated metal atoms on various supports will be extensively discussed together with the examples showing the research efforts to enrich the metal active sites from the pioneer works with metal loading below 0.2 wt% to the recently-reported SACs with metal loading over 20 wt%. Besides, there are still plenty of rooms to further improve the quantity and quality of metal loading on different supports, and outlooks of this scope is provided. We hope that this comprehensive review aids in the development of synthesis techniques for the new-generation SACs with richer active sites.