Photoelectrocatalytic reduction of carbon dioxide to methanol at cuprous oxide foam cathode

Abstract

In order to increase the reduction rate of CO₂ to methanol, the photoelectrocatalytic reduction of CO₂ at Cu₂O foam electrodes is proposed. The Cu₂O foam electrodes are fabricated by electrodeposition of Cu₂O coatings on copper foam substrates. The effect of bath pH and deposition time on the morphology and structure is investigated. The Cu₂O foam electrodes deposited at bath pH 10 for 20 min exhibit higher intensity of (111) diffraction peak. The photoelectrocatalytic performance of Cu₂O foam electrodes for CO₂ reduction to methanol depends largely on exposed Cu₂O{111} facets. At the applied potential of −1.5 V (vs. saturated calomel electrode), the optimum methanol concentration and the faradaic efficiency of methanol formation are obtained within 1.5 h, and they are 1.41 mM and 29.1%, respectively. The formation rate of methanol achieves 23.5 µmol cm⁻² h⁻¹ within 1.5 h.