Exponentially enhanced photocatalytic alkane production from biomass-derived fatty acid decarboxylation via self-heating-induced conformational inversion

Abstract

Heating is the most convenient means to enable unfavourable chemical reactions to upscale their application, but it is rarely used in photocatalysis because its driving force has always been identified as the intensity of excitable light and charge-separation efficiency, both of which are temperature-independent and negatively correlated. Herein, we report that the heat from relaxed incident light could significantly promote the conversion of long-chain fatty acids to alkanes with one less carbon atom (C_n−1 alkanes) mediated by TiO₂ photocatalysis for bio-fuel preparation. Employing high-boiling-point solvents could maximize the reaction temperature and allow the relaxed heat to accumulate within substrate molecules with amphiphilic groups as bond strain is made available by deforming the long C-chain onto the surface of TiO₂. In this way, photocatalysis could run at high temperatures (∼254 °C) and under very concentrated sunlight (∼26 W cm⁻²), with its scale upgraded from the traditional far less than mmol L⁻¹ level to the unprecedented mol L⁻¹ level for a single output.