This mini-review by Liu et al. explores the significant role of pH in electrochemical reactions, particularly in proton-coupled electron transfer (PCET) processes. The authors highlight how pH influences mass transport, the structure of the electrochemical double layer (EDL), and surface adsorption energy, all of which affect the overall electrochemical processes. The review focuses on three key reactions: hydrogen evolution reaction/hydrogen oxidation reaction (HER/HOR), oxygen reduction reaction/oxygen evolution reaction (ORR/OER), and carbon dioxide reduction reaction (CO2RR). Through a bibliometric analysis, the authors identify trends and advancements in the field, emphasizing the importance of pH in these reactions. They also provide a systematic overview of the mechanisms governing these reactions, particularly the influence of pH on both protons and electrons. Finally, the review discusses current challenges and suggests future research directions to enhance our understanding of pH's role in electrochemical reactions.This mini-review by Liu et al. explores the significant role of pH in electrochemical reactions, particularly in proton-coupled electron transfer (PCET) processes. The authors highlight how pH influences mass transport, the structure of the electrochemical double layer (EDL), and surface adsorption energy, all of which affect the overall electrochemical processes. The review focuses on three key reactions: hydrogen evolution reaction/hydrogen oxidation reaction (HER/HOR), oxygen reduction reaction/oxygen evolution reaction (ORR/OER), and carbon dioxide reduction reaction (CO2RR). Through a bibliometric analysis, the authors identify trends and advancements in the field, emphasizing the importance of pH in these reactions. They also provide a systematic overview of the mechanisms governing these reactions, particularly the influence of pH on both protons and electrons. Finally, the review discusses current challenges and suggests future research directions to enhance our understanding of pH's role in electrochemical reactions.