Catalytic reduction of CO2 by Al–Sn-CNTs composite for synthesizing formic acid

Electrochemical reduction and photocatalytic reduction of CO 2 have attracted more and more attention, but they also face the problem of low utilization efficiency of electricity and solar energy. In this study, a new strategy of applying a novel Al–Sn-CNTs composite in electrochemical corrosion process was proposed to reduce CO 2 without additional electricity and light. In the Al–Sn-CNTs/CO 2 system, micro galvanic cell with Al as anode and Sn or CNTs as cathode was formed, and CO 2 was reduced to formic acid on the cathode surface . The cumulative formic acid concentration of the Al–Sn-CNTs/CO 2 system achieved 21.18 mg/L within 60 min under the conditions of initial pH 9.0, Cl − concentration 10 mmol/L, and Al–Sn-CNTs composite dosage 2 g/L. Based on the morphology, crystal structure and electrochemical test results of the Al–Sn-CNTs composite, a possible mechanism of CO 2 reduction to formic acid in the Al–Sn-CNTs/CO 2 system was proposed.