Hydrogen production by water splitting with Al and in-situ reduction of CO2 into formic acid

• Hydrogen obtained by water spilling with Al was used for in-situ reduction of CO2 into formic acid.
• A considerable high formic acid yield of 64% with near 100% selectivity was achieved.
• CO2 reduction by waste metal is feasible.

The utilization of CO2 as a carbon source to produce useful chemicals could be regarded as a promising way to reduce CO2 emissions and to minimize global warming. In this study, hydrogen obtained by water spilling with Al was used for in-situ reduction of CO2 into formic acid. The common bulk Al was employed as a reducing agent to split water for reduction of CO2, possessing safe and convenient advantages. Results revealed that the hydrogen production from water with the oxidation of Al can be enhanced in the presence of NaHCO3, as a source of CO2, which can be in-situ reduced into formic acid. A considerable high formic acid yield of 64% with near 100% selectivity was achieved. Additionally, experiments of mix-metals containing Fe, Al, Cu. Zn and Sn with NaHCO3 were conducted to investigate the Electronic waste (E-waste) as reductant for reducing CO2 and more than 60% yield of formic acid were obtained, indicating that CO2 reduction by waste metal is feasible. This study can assist in developing an efficient and economical process for conversion of CO2 to value-added chemicals.