Interface-Rich Highly Oxophilic Copper/Tin–Oxide Nanocomposite on Reduced Graphene Oxide for Efficient Electroreduction of CO<sub>2</sub> to Formate
Manjunatha Kempasiddaiah, Rajib Samanta, Sonali Panigrahy, Sudip Barman
Abstract
In recent days, it has been reported that bimetallic electrocatalysts can increase the activity for electrochemical formate (HCOO – ) production during CO 2 reduction. However, they still have some apparent drawbacks such as poor selectivity and durability. In the current work, notable improvements in the electrochemical CO 2 reduction (CO 2 RR) to formate production were accomplished by incorporation of reduced graphene oxide (rGO) into nanostructured bimetallic CuSnO x electrocatalysts (Cu x SnO x /rGO). The interface-rich mixed crystalline–amorphous nanostructured Cu 0.33 SnO x /rGO nanocomposite is able to enhance the electrocatalytical activity, resulting in conversion of CO 2 to formate with lower overpotential of 590 mV vs RHE. The control experiments show that the presence of SnO x in the catalyst considerably increased electrocatalytic activity and product selectivity toward formate production. Further, the increased oxophilicity of the Cu 0.33 SnO x /rGO nanocomposite supports the plausible CO 2 reduction mechanism through the formation of bicarbonate intermediate, as demonstrated by CO stripping studies. The Cu 0.33 SnO x /rGO had maximum formate faradaic efficiency (80.62%) at lower potential of −0.69 V (RHE), which is 2.09 and 1.85 times better than those of CuSnO x /rGO and Cu 3 SnO x /rGO nanocomposites, respectively. The catalytic performance may be attributed to synergistic interaction, the presence of interfaces, higher electrochemical surface area, and the mixed crystalline–amorphous nature of Cu 0.33 SnO x /rGO nanocomposite. Thus, the obtained results gave rise to a practical method for boosting the activity and product selectivity of electrocatalysts for efficient CO 2 conversion.