From biomass to fuel: Advancing biomass upcycling through photocatalytic innovation

In the face of escalating energy demands and environmental degradation, the transformation of biomass into gaseous fuels such as hydrogen (H₂) and carbon monoxide (CO) has become pivotal in renewable energy research. Photocatalysis, recognized as a promising and sustainable approach, enables the conversion of biomass into fuels and value-added compounds by harnessing light energy to catalyze chemical reactions under ambient conditions. The key to the success of this technology is the development of photocatalysts that can effectively absorb and convert light for these reactions. Since photocatalytic conversion of biomass into value-added fuels is a new and innovative research direction, a comprehensive and thorough review systematically summarizing and outlining the prospects for this specific topic is lacking until now. Our comprehensive review, one of the pioneering works in systematically summarizing this emerging research avenue, illuminates the intricacies of biomass photoconversion, from fundamental principles to the cutting-edge design of novel photocatalysts, including cost-effective and sustainable metal-free variants like graphitic carbon nitride. In this regard, this review starts with the fundamental principles and mechanisms of biomass photoconversion and centers on the design of state-of-the-art photocatalysts. We begin with noble metals, then move to cheaper metal-based alternatives, and finally place emphasis on metal-free graphitic carbon nitride. Through strategic modifications, including heterojunction construction, doping, and morphology optimization, we highlight significant strides in enhancing the photocatalytic performance of these materials. Our discussion not only encapsulates the recent advancements but also projects into the future, suggesting directions for research that could unlock the full potential of photocatalytic technology in renewable energy production. We aim to offer insight for designing next-generation photocatalysts, paving the way for future breakthroughs in the field of biomass upcycling.