Enhanced Ethylene Formation from Carbon Dioxide Reduction through Sequential Catalysis on Au Decorated Cubic Cu₂O Electrocatalyst

Abstract

Electrochemical reduction of carbon dioxide to fuels has been recognized as a perspective way to address the environmental and energy issues. Herein, the novel Au decorated Cu 2 O electrocatalysts were synthesized via the galvanic replacement reaction and the successive pre-reduction by linear voltammetry (LSV) method. In contrast to Cu 2 O, CO formation became dominant over HCOOH and H 2 on Au x Cu 2 O, and a remarkably enhanced selectivity of C 2 H 4 was obtained beyond À 1.1 V vs. RHE. Among them, Au 0.02 Cu 2 O exhibited the highest Faraday efficiency (FE) of C 2 H 4 of 24.4 % at À 1.3 V vs. RHE, which was as high as 2~2.5 and 5 times of those on other two Au x Cu 2 O and bare Cu 2 O, respectively. Meanwhile, it is demonstrated that the optimal ratio of Au/Cu was essential for effective sequential catalysis between Au and Cu 2 O to enhance CÀ C coupling. Furthermore, the effect of copper states resulting from different pre-reduction methods on the selectivity of C 2 H 4 was explored. A half decrease of C 2 H 4 FE was observed on HPR-Au 0.02 Cu 2 O (high potential reduced) relative to the LSV reduced Au 0.02 Cu 2 O, which was ascribed to the different content of Cu 0 and residual Cu + in two catalysts. Our results demonstrate an effective approach to construct Cu 2 O based bimetallic catalysts for ethylene formation from CO 2 .

Effect of Charge on Carbon Support on the Catalytic Activity of Cu2O toward CO2 Reduction to C2 Products

“…The redox behaviors of the NG/Cu, BG/Cu, and rGO/Cu were investigated by cyclic voltammetry (CV, Figure S29). The catalysts exhibit cathodic peaks assigned to the reduction of CuO to Cu 2 O (C1), further reduction to Cu (C2) and HCuO 2– (C3), and anodic peaks associated with the oxidation of Cu to Cu 2 O (A1) and Cu 2 O to CuO (A2) . NG/Cu presents a smaller A1 peak area than BG/Cu and rGO/Cu, suggesting that the NG substrate improves the resistance to reduction of Cu 2 O.…”

“…The catalysts exhibit cathodic peaks assigned to the reduction of CuO to Cu 2 O (C1), further reduction to Cu (C2) and HCuO 2− (C3), and anodic peaks associated with the oxidation of Cu to Cu 2 O (A1) and Cu 2 O to CuO (A2). 45 NG/Cu presents a smaller A1 peak area than BG/Cu and rGO/Cu, suggesting that the NG substrate improves the resistance to reduction of Cu 2 O. The area of the A2 peak was larger than that of the A1 peak, which indicates the dominance of Cu(I) in the mixed Cu states of catalysts.…”

Conversion of carbon dioxide into solid carbon materials – a mini review

“…The electrocatalytic CO 2 reduction reaction (CO 2 RR) refers to the electrochemical reduction of CO 2 to desired products, 9 e.g. C1 products (carbon monoxide, 10 formic acid, 11,12 methanol, 13 methane [14][15][16] ), C2 products (ethylene, [17][18][19][20] ethanol [21][22][23] ), and C3 products (propanol 24 ). The first step of CO 2 RR is the activation of CO 2 into a radical intermediate.…”