Catalyst-Free Reduction of Co2: Achieved by Spontaneous Generation of Hydrogen Radicals Through Nanobubbles-Water System

Abstract

Hydrogenation reduction of CO2 typically requires the assistance of catalysts or harsh reaction conditions. In this study, we present a pioneering catalyst-free approach for the conversion of CO2 to formic acid and oxalic acid in aqueous solution under ambient temperature and pressure conditions. This novel approach involves generating CO2 nanobubbles in water. The hydrogen radicals spontaneously generated by the nanobubbles are responsible for the hydrogenation reduction of CO2. With the aid of isotope labeling experiments and H/D kinetic isotope effect theory, we revealed that H2O served as the proton donor in the CO2 reduction process. This research introduces a novel strategy for CO2 conversion and provides a deeper understanding of the properties and functions of nanobubbles.

Keywords: nanobubble, CO2 reduction, free radicals, isotopic kinetic effect