Several studies have shown the feasibility of CO2 reduction into valuable chemicals such as methane, ethylene, and syngas. However, the main challenges of this process are to obtain high activity, stability, and selectivity into desired products. In this process, the catalyst is playing a big role to produce high amounts of hydrocarbons. Many types of catalyst can be used, however Cu-based of gas diffusion electrode (GDE) is the focus on this assignment. Therefore, in this project, the ink compositions (copper, solvent, and polymer) on a gas-diffusion layer will be investigate by using different solvents and polymers. The goal is to compare the effect of ink compositions to increase the catalytic performance and also to evaluate the determinant physical/chemical properties in CO2 reduction.