The extent of pH rise is dependent on RF of the catalyst, with higher surface porous catalysts producing higher surface pH due to the higher number of active sites. Consequently, local pH within varies within the catalytic bed, depending on the uniformity of distribution of surface active area. The progressive variations in the local pH along the catalytic bed in mass transport models stands in contrasts with many experimental studies on the impact of pH on CO2RR using copper electrocatalysts. These studies typically examine impact of a discrete pH values (for example pH =1, 2, 7, 12/13) on various voltages without providing a comprehensive range of pH values on product selectivity of CO2RR. Future mechanistic models can ensure that wider ranges of pH values as a function of applied voltage are captured.