One of the greatest challenges in CO 2 RR is the inherent stability of carbon dioxide molecules. The energy required to break the C--O bond is about 750 kJ/mol, about twice the value for forming C-H, C-C, and C-O bonds . Consequently, a substantial applied potential is necessary for the reaction to occur. Furthermore, the hydrogenation of CO 2 can yield multiple products, limiting the efficiency of the process , and the competition with the hydrogen evolution reaction (HER) further complicates the process. These issues have drawn the attention of a considerable amount of research regarding CO 2 RR . The goals are i) to reduce the energy required for the reaction to happen, ii) to improve the selectivity of the process, and iii) to decrease the H 2 formation. These conditions are reflected in the following metrics measured in laboratories and commonly reported in the literature: the applied potential and the light intensity associated with the energy furnished to the system, the faradaic efficiency (FE), and the formation rate of a catalyst toward a specific product, indicating the selectivity of the reaction. Different approaches have been utilized for this task, each with its own advantages and limitations, resulting in distinct performances and outcomes. Keeping track of these metrics is paramount to understanding how research has progressed over the years, and providing some guidance for future works in this field.