Behavior And Influence Of Bubble In Hydrogen Production From Electrolyzed Water

Alkaline electrolysis of water for hydrogen production is currently a relatively common hydrogen production method with extremely high gas purity.Due to its low cost and simple experimental conditions,the current commercial level is the highest among several electrolysis water hydrogen production methods,but its efficiency is relatively low.Therefore,the current research on hydrogen production from alkaline electrolysis water is all on improving its hydrogen production efficiency.However,the current research focuses on the overall structure of the electrolytic cell,and there is very little research on the microstructure,and there is a lack of understanding of the basic principle of the microscopic angle of the bubbles in the process of electrolysis of water for hydrogen production.This paper mainly studies alkaline electrolyzed water from the perspective of microscopic microlayer and bubbles.Firstly,according to the research on the formation of the microlayer at the bottom of the bubble and the study of the hydrophilicity and hydrophobicity of the electrode surface on the formation characteristics and influence of the bubble in the hydrogen production process,the corresponding experimental device and experimental system are designed.Secondly,in this paper,a two-dimensional visual laser interference experiment bench and an observation experiment bench for the behavior of bubbles and their effects in the process of electrolysis of water to hydrogen are built.Aiming at the laser interference test bench,this paper uses the laser interferometry method to measure the bottom of the hydrogen bubbles generated during the electrolysis of water to produce hydrogen with high precision.Aiming at the observation experimental bench for the behavior characteristics of bubbles and their influences in the process of electrolysis of water for hydrogen production,two high-speed cameras are used to simultaneously photograph the behavior characteristics of hydrogen bubbles on the surface of the working electrode from the front and side.Finally,the study found that in a single bubble growth cycle,with the progress of electrolysis,the thickness of the microlayer first became thinner and then remained constant until the microlayer disappeared when the bubbles were detached,and the microlayer structure was a meniscus.In the early stage of bubble growth,the variation law of bubbles near the center of the microlayer and farther away from the center of the microlayer is roughly the same.In the late stage of bubble growth,it is far from the center of the microlayer,and the thickness of the microlayer basically does not change,that is,the solution is basically no longer electrolyzed.At this time,the solution is mainly electrolyzed near the center of the circle.At a current density of200 m A/cm2,when carbon paper electrodes with contact angles of 140°,83°,and 68°were used as working electrodes,the cathode overpotentials were 1.55 V,1.18 V,and1.09 V,respectively.When the temperature decreases,the cathode overpotential and bubble detachment diameter tend to decrease,while the number of nucleation points and the bubble detachment frequency increase.Under the same experimental conditions,the cathode overpotentials of 140°,83°,and 68° carbon paper electrodes with catalysts on the surface are reduced by about 24%,11.7% and 16.9% compared with those without catalysts,which increases the detachment frequency of bubbles and reduces the number of bubble nucleation points on the electrode surface.