CO2 reduction into formic acid under hydrothermal conditions: A mini review

Converting CO2, a major component of greenhouse gas in the atmosphere, into value-added fine chemicals is beneficial from environmental and economic aspects. Except for various methods for CO2 reduction such as thermal catalysis, photocatalysis, electrocatalysis and biological reduction, hydrothermal reduction of CO2 to organics is becoming a novel and promising strategy. The hydrogen formed in situ from high-temperature water could avoid the serious issues of hydrogen storage and transportation. This paper summarizes the recent advances on CO2 conversion to formic acid with metal- and biomass-based compounds under hydrothermal conditions mainly focusing on the role of high-temperature water, autocatalysis mechanism of metal reductants, and interfacial catalysis mechanism of metal/metal oxides. The effects of several experimental variables including temperature, reaction time and pH of the solution on formic acid yield are systematically illustrated as well. Finally, future efforts for fundamental researches and industrial applications of hydrothermal CO2 reduction are discussed.

Automated summary

Converting CO2 into value-added chemicals is environmentally and economically beneficial, and hydrothermal reduction is a promising strategy. This paper summarizes the recent advances in converting CO2 into formic acid using metal- and biomass-based catalysts under hydrothermal conditions, and discusses the effects of several experimental variables on the formic acid yield.