Nowadays, different studies reveal that the level of carbon dioxide in the atmosphere is rising continuously and disrupting the environment due to its cause of global warming. For this reason, advanced and emerging technologies associated with the conversion of CO₂ are highly essential. Among many methods, electrocatalytic reduction of CO₂ is the most efficient and easy way to reduce CO₂ into CO, alcohols, hydrocarbons, and other products. Bimetallic nanoparticles of Au and Cu and the parent monometallic of each metal are synthesized and supported on functionalized multi-walled carbon nanotubes (MWCNT). The supported bimetallic nanoparticles are dispersed uniformly on fiber carbon papers (CP). To evaluate and correlate the performance of the reduction, tuning the size and structural properties of Au-Cu electrocatalyst are investigated by incorporating polyvinylpyrrolidone (PVP) for electrochemical reduction (ECR) of CO₂. Different amounts of PVP are applicable for each bimetallic and monometallic electrocatalysts (AuCu/MWCNT/CP, Au/MWCNT/CP and Cu/MWCNT/CP). The significant role of PVP on the atomic distribution of Au-Cu nanoparticles (NPs) and its particle size have been studied in advance. X-ray absorption near-edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) are key measurements to estimate the alloying extent of Au Cu in the alloy including the coordination numbers of each metal. The electrocatalysts, which are prepared with PVP, have a better activity and selectivity compared to the bimetallic synthesized without PVP. The amount of PVP affects the structure and significantly minimizes the size of NPs that influences the activity and selectivity of products. At -0.91 V vs. RHE, the faradaic efficiency (FE%) of CO using Au-Cu/CNT (1.5 g PVP) was around 89%, but in the absence of PVP, the same test resulted in ~72%, indicating the effect of PVP in the product selectivity.