Experimental investigation of hydrogen and oxygen bubble growth on platinum microelectrodes of different sizes

Bubble coverage on the electrode surface significantly reduces the efficiency of water electrolysis. This study investigates the effects of current density and microelectrode size on the growth and detachment dynamics of hydrogen and oxygen bubbles during water electrolysis. A high-speed camera is used to capture the dynamic behavior of bubble evolution and electrochemical measurements are conducted to record the instantaneous potential fluctuations. The results reveal that the bubble detachment size depends on the electrode size. At identical current densities, as the diameter of microelectrodes decreases, the generated hydrogen and oxygen bubbles exhibit smaller detachment diameters. Moreover, as the current density increases, the detachment diameter of bubbles increases. The results indicate that solutal Marangoni convection plays a critical role in the detachment of bubbles. These findings provide critical insights into bubble dynamics for optimizing electrolysis efficiency.