Electroreduction of CO2 to High-Value Products Using Selenide Based Electrocatalysts

Abstract

Electrochemical conversion of carbon dioxide (CO2) to useful chemicals presents both the potential for advantageous processes to the industry and for environmental benefits. Anthropogenic gas emissions has increased to a new level (413 ppm) in past few years. Concerns are high about impacts on climate due to high CO2 gas levels. Intergovernmental Panel on Climate Change (IPCC) report has indicated a strong risk of crisis as early as 2040 which includes worsening food shortages and wildfires, and a mass die-off of coral reefs.3 Fossil fuels has been predicted to last only for 100 years. Also the common renewable resources like wind energy or solar energy depends on the whim of weather. CO2 has been believed to cause the rise in temperature of earth’s atmosphere by 1°C. If we can use CO2 to produce energy then it can prove an everlasting energy source. Copper based catalysts are mostly active for the electrochemical reduction of CO2. Cu nanocrystals when used for CO2 electrochemical reduction give some C2 products which contain a C-C bond. Cu nanowires also reduced CO2 to CO with a faradaic efficiency of ∼50% at a moderate overpotential of 490 mV. Electrochemical reduction of CO2 if incorporated in the modern day energy resources can serve two purpose: make environment clean and provide energy too. In this work we have shown for the first time, electrocatalytic activity of Cu2Se for CO2 electroreduction to value-added chemicals. The Cu­2Se catalyst was synthesized hydrothermally and was dropcasted on Carbon Fiber paper substrate (CFP) using very low quantity of nafion as binder. The Cu2Se modified CFP served as the working electrode for CO2 electroreduction and the electrochemical measurement was measured in KHCO3 electrolyte under flowing CO2 using a two-compartment electrochemical cell. The electrocatalyst was characterized by XRD, XPS, SEM, TEM, and EDS for morphology, and elemental chemical compositions. It was observed that the reduction products could be controlled by tuning the reduction potential, and a highly selective formate production was obtained at a higher potential with a high total current density approximately 30 mA cm-2. C2 products such as ethanol and acetic acid were obtained as reduction products. The details of catalyst synthesis, characterization and activity will be presented in the meeting.