Materials and Reaction System Design Advances in Photocatalytic Decarboxylation of Fatty Acids to Low-Carbon Liquid Fuels

Abstract

The decarbonization of the liquid fuels industry is vital for sectors reliant on energy-dense hydrocarbons, including aviation, shipping, and heavy-duty transport. Fatty acids derived from biomass and waste lipids are abundant renewable feedstocks for drop-in fuel production. Photocatalytic decarboxylation has emerged as a promising solar-driven route to convert fatty acids into hydrocarbon fuels under mild conditions. This review critically examines recent advances and future perspectives in photocatalytic fatty acid decarboxylation, with particular emphasis on reaction mechanisms, catalyst design, and reactor engineering for the selective production of low-carbon liquid fuels. We first discuss feedstock availability and map fatty acid chain lengths to gasoline-, jet-, and diesel-range products. Reaction pathways are then analyzed in terms of hydrogenation to Cn–1 alkanes and dimerization to longer-chain hydrocarbon products. Selectivity is governed by radical generation and stabilization, hydrogen availability, surface confinement, solvent effects, and reaction atmosphere. Recent developments in semiconductor photocatalysts, cocatalysts, and active site design are reviewed to elucidate how surface chemistry and hydrogen management direct pathway selectivity. Ultimately, we propose future research directions that integrate feedstock characteristics, catalyst architectures, and reactor configurations through functional active site engineering and process intensification. By establishing design principles that link molecular-scale reaction control with system-scale performance, this review provides a framework for advancing photocatalytic routes to sustainable liquid fuels.