Here, we introduce an innovative approach that abstracts from the concept of a well-defined active site and accounts for the diffusion of reaction intermediates among diverse active sites exposed on nanoparticle (NP) catalyst surface. Moreover, we propose a novel ansatz to rationally simplify the catalytic network in the microkinetic model by selecting the most catalytically relevant elementary steps involved in the reaction mechanism. As a result, the developed approaches allow us to obtain profound insight into the CO2 hydrogenation mechanism into C2 compounds and extrapolate our results to the formation of C3+ products. In this study, we focus on Cu-based nanocatalysts due to their widespread use in both electro-and thermocatalytic CO2 hydrogenation, as well as a major component in multimetallic catalysts alongside metals like Co and Fe. Moreover, we extend our analysis to CO2 hydrogenation on Pd catalysts, which are commonly used for the hydrogenation of other compounds despite a very distinct electronic structure from Cu.