Synthesis and characterization of bimetallic metal oxide on graphene support electrocatalyst for carbon dioxide conversion

Abstract

The furthermost challenge of twenty-first century is increasing amount of green house gas, Carbon dioxide (CO2), in the atmosphere due to fossil-fuels and energy-demanding industries. The concerns of problems like global warming and climate change has led to initiate global efforts to reduce the emission and concentration of CO2. Replacement of fossil fuels with renewable energy sources, to reduce CO2 emission is considered from past years. Due to the increase in atmospheric temperature, this problem has attracted the attention of scientific community globally. Carbon dioxide capture and sequestration (CCS) technology has appeared as a first solution to this problem and has gained higher interest, as it could decrease the amount of CO2 into atmosphere. However, higher energy consumption and the risk of leakage of stored CO2 in this process, prevents its large scale up development. Instead of CO2 capture and sequestration its utilization to produce useful chemicals is a better solution. This approach not only provides fuels and useful chemicals but also helps in reducing the amount of CO2 in the atmosphere and cost of CCS process. Many techniques are available for CO2 reduction, such as photochemical, radiochemical, biochemical, electrochemical and thermochemical reduction. The reduction of CO2 becomes a challenging task due to its highly stable nature. Out of all available techniques, electrochemical reduction is believed to be best owing to its advantages, such as controllable electrode potential, reaction temperature, production of alcohols, and hydrocarbons from renewable energy sources and easy for scale up applications. Numerous challenges are associated with the electrochemical reduction of CO2, i.e. occurrence of hydrogen evolution reaction (HER) and formation of multiple products. It is essential/desirable to develop an appropriate electrocatalyst which can produce chemicals selectively with high faradic efficiency and should be durable. Copper based electrocatalysts are found to be attractive and have been extensively used for electrochemical reduction of CO2 due to its unique capability to catalyze the formation of hydrocarbons. Many researchers have performed their work by modifying copper electrode and found interesting results. In this work, graphene supported bi-metallic metal oxide electrocatalyst (Cu2O-ZnO) was synthesized for its use in electrochemical reduction to convert CO2 to chemicals/fuels. The synthesized electrocatalyst were characterized using various techniques namely XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy), Raman spectroscopy and FE-SEM (Field emission scanning electron microscopy). On the basis of characterization results, prepared electrocatalyst is found suitable to be used for electrochemical reduction of CO2 to fuels/chemicals.