CO2 Reduction into Syngas Using NiZn Bimetallic Electrocatalyst

Abstract

The level of CO2 in the atmosphere is continuously increasing, making it the largest contributor to greenhouse gases, which are responsible for global warming and climate change. To reduce CO2 concentrations, several methods have been developed and implemented. One such method is the electrochemical conversion of CO2 into fuel. In the CO2 reduction electrochemical process, the role of a catalyst is very important to obtain a selective product with an efficient process. The stages in this study consisted of 3 stages, namely catalyst synthesis, testing of the electrocatalytic activity of the catalyst, product characterization. The NiZn electrocatalysts were synthesized with various variations, namely Zn100%, Ni25% Zn75%, Ni50% Zn50%, Ni75% Zn25%, and Ni100%. Galvanostatic electrodeposition was carried out at a current of -1A.cm-2 for 30 seconds. The results of the performance test using the LSV method show that the best electrocatalytic performance for reducing CO2 is Ni50% Zn50%, which has the highest current density of -45.88 mA.cm-2 at a potential of -1 V vs RHE. The chronoamperometry method also showed the same results, where the Ni50% Zn50% electrocatalyst had the most negative current density of –44.31 mA.cm-2. The GC results showed that as the proportion of Zn in the catalyst increases, the ratio of CO gas produced also increases. On the other hand, Ni is more favorable for producing H2 gas. For an electrocatalyst with a Ni50% and Zn50% composition, it produces syngas with a 1:1 ratio. The HPLC results showed that the NiZn electrocatalyst was not a selective catalyst for formic acid production.

Keywords: CO2 reduction, NiZn electrocatalyst, Synthesis, Electrodeposition