Based on the preceding analysis, it becomes evident that determining 𝑗 0 and ∝ relies on the assumption of a single linear kinetic region, which often proves inaccurate. Typically, this approximation is confined to a narrow potential range around the equilibrium voltage. However, over broader voltage ranges, the assumption of linearity is often invalidated. Microscopically, log(J)-V curves exhibit nonlinear electrode kinetics (kinetically limited currents), particularly at higher (negative) voltages, due to the influence of solvent reorganization energy (λ) as per the more rigorous Marcus-Hush-Chidsey (MHC) theory. In the utility of linear approximations for log(J)-V responses, it is common to encounter multiple kinetic regions covering a broad spectrum of applied voltages, particularly in cases involving complex catalytic activities with multi-step reactions and products. Usually, classification of these regions is left to the expertise and judgement of the researcher. The subjective nature of defining boundaries between these regions for extracting Tafel slopes in log(J)-V responses can introduce errors into computational models. Recent studies by Agbo et al. and Limaye et al. have addressed this issue for a single Tafel slope. Thus, although B-Ve in Eq. 2 provides a framework for analytically elucidating the electrode kinetics, it is fundamentally rooted in empirical observations and assumptions. It is primarily designed for single-electron transfer reactions and certain multistep reactions whose rate-determining step (RDS) is intrinsically much slower than the other steps. Moreso, the applicability of B-Ve can be rather limited in complex electrocatalytic systems with several elementary steps because the overall reaction kinetics are influenced by the factors beyond electron transfer. This is the situation in the case of the cathodic CO2 reduction reaction (CO2RR), especially on Cu electrocatalysts, which is the emphasis of this work. In conducting CO2RR on copper electrodes, researchers uncovered a fascinating complexity, unveiling the existence of no less than 16 products, which comprise predominantly hydrocarbons amongst a diverse array of alcohols, aldehydes, ketones, and carboxylic acids. The mechanistic routes leading to the formation of these products on copper reveal that certain pathways are activated by availability of protons, electrons or a concerted/sequential proton and electron transfer processes and potential. Other factors, such as the coverage of reactants/intermediates, multiple competing reaction pathways, surface adsorption/desorption kinetics and additional chemical reaction steps (typically from side reactions), introduce complexity to the identification of a definitive RDS. This complexity is further exacerbated by the influence of the catalyst particles facet structure and surface reconstruction on product selectivity. Experimental observations of CO2RR reveal that conventional concept of a single Tafel slope is inadequate in explaining the electrode activity of certain products generated on Cu electrocatalysts for the CO2RR. Therefore, using exchange current density and Tafel slopes to predict current densities is often inaccurate. Figs. 2a and 2b illustrate multiple distinct kinetic regions for typical log(J)-V responses of a hydrocarbon product specie and hydrogen product specie respectively. The multiple kinetic regions arise from the complex nature of multi-step reactions, the interlocking relationship between the CO2RR and side reactions, such as HER and the formation of various heterogenous products, where coverage of reactive intermediates is dependent on the electrode potential, surface concentrations of reactants, and local pH. In the CO2RR literature, it has been observed that as applied voltage changes, distinct voltage regions emerge in which reaction mechanism transitions from one dominant pathway to another. In fact, Tafel slope is dependent on the applied voltage and specie surface coverage. For instance, in the case of Cu2Oderived Cu catalysts, Huang et al discovered that ethylene production is notably enhanced at a voltage of -0.98V vs RHE, while methane generation is reduced at -1.13 V vs RHE. Production of ethylene was observed when production of CO plateaued at -0.63 V vs RHE. This indicates the switch from one kinetic regime to another, orchestrated by specific applied voltages and coverage, or pH, for which a particular product formation becomes prevalent within a voltage region.