Development of new electrocatalysts with high electrocatalytic activity and stability is of great importance in the production of hydrogen fuel. Numerous methods have been established to increase the activity of electrocatalysts, including increasing active surface area and improving intrinsic catalytic activity. However, the electrochemical water splitting is a gas-involving reaction in which hydrogen and oxygen bubbles are formed on cathode and anode surfaces, respectively, which lead to an increase in overpotential of electrochemical reactions. In this review, recent advances have been complied to understand the behavior of hydrogen and oxygen bubbles separation from the surface of electrodes during water splitting. Initially, various types of resistance in water splitting have been discussed, and further progress has been discussed to improve the separation of bubbles and thus improve electrocatalytic activity. These improvements include surface nanostructuring and making superaerophobic surfaces where bubbles can easily be removed from the surface, resulting in lower bubble resistance. Furthermore, the use of magnetic, supergravity and ultrasonic fields are among additional methods for fast separation of bubbles from the surface and improving catalytic activity This paper presents a review of a research pathway for creating 3D nanoarrays to improve the bubble separation behavior on the surface and improve electrocatalytic properties.

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