High-flux alkane production from bio-derived fatty acid decarboxylation enabled by photothermal conversion effect

Abstract

Heating is the most straightforward means to achieve rapid, high-throughput production for thermal catalytic reactions, but photocatalysis reactions rarely use it because its intrinsic driving force depends on the effective separation of photogenerated charges, which generally shows little or sometimes negative dependence on temperature. Here we demonstrate that the heat generated by the photothermal conversion of Bi₂O₃ nanoparticles can be utilized to dramatically accelerate the photocatalytic decarboxylation of long-chain fatty acids to C_n-1 n-alkanes. Using high-boiling solvents to maximize reaction temperatures, C_n-1 n-alkane can therefore be obtained in very high concentrations (e.g., ∼0.5 M) in a single operation, 5 orders of magnitude higher than the previous both semiconductor photocatalytic and algal photoenzyme transformations limited in the range ∼ 1–10² μM. Comprehensive characterizations unveil that the heat from incident light enables the standing C-chain at low temperature down onto the surface of catalyst, which allows the photoinduced hole/electron to readily approach and react with the more strained C-COO⁻ bonds. This study manifests that the vast majority of incident light energy can be utilized in the form of heat to improve the reaction efficiency to as meet industrial output levels as possible.