The influence of solution pH on electrocatalytic reactions is multifaceted, including intrinsic pH effects and local pH effects. In broad terms, changes in solution pH impact reaction kinetics by inducing shifts in both proton activity and absolute potential of the electrode (i.e., versus the SHE). Given that many electrocatalytic reactions involve proton and electron transfers, variations in pH play a pivotal role. Moreover, the proton donor or oxidant involved in the reaction may transition from proton/hydroxyl to water molecules when pH varies in a wide range. Additionally, for reactants engaged in acid-alkaline equilibrium, such as formic acid and formate, the concentration of the reactant is influenced by the solution pH. These influences are termed as intrinsic pH effects as they collectively shape the overall properties of electrocatalytic reactions.