One‐step photothermal synthesis of biofuels from high‐acid‐value non‐edible oils with adjacent Cs single atoms at ambient conditions

Abstract Thermocatalytic biofuel production via (trans)esterification can be highly enabled by solid alkali catalysts, while often suffering from serious saponification and unsatisfactory catalyst reusability when the bases are directly used for high‐acid‐value oils. Herein, room temperature single‐step upgrading of various non‐edible oils (acid values: 6.6 − 21.5 mg KOH g −1 ) to biodiesel (> 97% yields) after 37 min with satisfactory fuel properties was achieved under solar irradiation over a renewable heterogeneous Lewis base catalyst (Cs/GL‐4), which was composed of adjacent Cs single atoms (ACs SA) anchored on graphene‐like (GL) biomaterial. Infrared thermal imaging showed that Cs/GL‐4 had good photothermal performance, while quantum calculations and COMSOL multiphysics disclosed that ACs SA exhibited the prominent pyroelectric effect which was closely correlated with super‐alkalinity and good acid resistance, both contributing to rapidly producing biodiesel of high efficiency under ambient conditions (25 °C). Moreover, the pronounced activity and reusability of Cs/GL‐4 were verified by reaction kinetics and recycling studies. The life cycle assessment indicated significant advantages in terms of energy savings (68.86 MJ kg −1 ) and negative carbon emission (− 2.42 kg −1 ) associated with the photothermal‐driven protocol for renewable diesel production, suggesting its relatively positive overall environmental impact. The electronic structure of adjacent atomic sites further enhanced by the photothermal effect provides an alternative reference for the one‐step and mild upgrading of raw biomass.