Au supported on Ti has gained popularity as a highly stable and efficient catalyst in various fields. In this study, we report the use of Au/Ti as electrocatalysts for both electrochemical (EC) CO2 reduction and CO reduction in a phosphate buffer electrolyte. We demonstrate, for the first time, that the dominant gas products are CO, H2, and CH4, and that the EC CO2 reduction process yields long-chain hydrocarbons (CnH2n and CnH2n+2, n = 2–7) resulting from initial CO2 adsorption. Similarly, CH4 and long-chain hydrocarbons are significantly produced by EC CO reduction via direct CO adsorption on the catalyst surface. We also demonstrate an EC method for mimicking Fischer-Tropsch synthesis, which involves both indirect CO2 and direct CO adsorptions. By analyzing the weight distribution using the Anderson-Schulz-Flory method, we were able to understand the surface polymerization reaction, which we attributed to CO and CHx insertion. These findings are highly unique and represent a significant advancement in the development of electrochemical methods and electrocatalysts for producing long-chain hydrocarbon fuels.