Radical‐Mediated Photocatalysis for Lignocellulosic Biomass Conversion into Value‐Added Chemicals and Hydrogen: Facts, Opportunities and Challenges

Abstract

Photocatalytic biomass conversion into high‐value chemicals and fuels is considered one of the hottest ongoing research and industrial topics toward sustainable development. In short, this process can cleave Cβ−O/Cα−Cβ bonds in lignin to aromatic platform chemicals, and further conversion of the polysaccharides to other platform chemicals and H2. From the chemistry point of view, the optimization of the unique cooperative interplay of radical oxidation species (which are activated via molecular oxygen species, ROSs) and substrate‐derived radical intermediates by appropriate control of their type and/or yield is key to the selective production of desired products. Technically, several challenges have been raised that face successful real‐world applications. This review aims to discuss the recently reported mechanistic pathways toward selective biomass conversion through the optimization of ROSs behavior and materials/system design. On top of that, through a SWOT analysis, we critically discussed this technology from both chemistry and technological viewpoints to help the scientists and engineers bridge the gap between lab‐scale and large‐scale production.

Efficient catalytic oxidation of biomass to formic acid coupled with low-energy formaldehyde production from methanol

“…The diminishing fossil resources and the growing concerns about environmental issues have stimulated the utilization of renewable and clean bioresources for energy and chemicals. [1][2][3] As the largest renewable carbon resource, lignocellulosic biomass has great potential to replace fossil resources for the production of chemicals and fuels. Formic acid (FA) is a bulk chemical widely applied in textile, pharmaceutical, leather, agriculture, rubber, and chemical syntheses and in other fields.…”