Single Gas Bubble Evolution Behavior On Pt Electrodes Of Hydrogen Evolution Reaction

With the industrialization revolution,the collection and utilization of fossil energy has been unable to keep up with the progress of science and technology and the development of society.In today's society,the foundation is energy,and it 1s also one of the key difficulties in technological innovation.In order to solve the problems of energy crisis and environmental pollution,improving energy efficiency and finding the clean and sustainable alternative energy sources have became one of the primary tasks of today's scientific researchers.The gas evolution reaction(GER)is one of the foundations of a series of electrochemical industries,so its meticulous research is particularly important.The nanoarray electrodes not only have excellent electrochemical performance,but also have superaerophilic property which is beneficial to improve the mass transfer behavior in GER.So the nanoarray electrodes become a research central issue of GER catalysts.Although scientists have successfully achieved significant improvements in the intrinsic properties of electrocatalysts,studies on the effects of electrode structure and wettablilty on bubble growth behavior is quite limited,lacking accurate kinetic models.In this thesis,a series of nanostrucetured electrodes with different morphologies and electrodes with different wettability were constructed to find out the bubble growth behavior on the surface of structured electrodes and their related electrochemical properties,constructe and analyze the kinetic model and the causes of bubble growth.To further understand the influence of wettability on bubble growth and the fimdamental reason why nanoarray electrodes are superior to the other electrodes.According to this,design a specific structure to obtain much more excellent and efficient electrodes which have high energy efficiency of electrocatalytic reaction of GER.The specific research contents are as follows:Adjust the experimental method to determine the optimal preparation method of platinum nanoarray electrode.Through contact angle and bubble adhesion test,it was found that pine-shaped platinum nanoarray,platinum nanosphere and flat platinum electrode all showed hydrophilicity,and pine-shaped nano-array had the smallest bubble adhesion(about 4 ?N)which is superhydrophilic,so that small size and rapid detachment of the bubble evolution can be achieved.Making its electrochemical performance is superior to other structural electrodes.And the relationship between radius and time of single macro-bubble evolution on the electrode is fitted and is highly match the mathematical equation of the form-R(t)=?tx.And the R-t time coefficient(?R)of the three hydrophilic electrodes are slightly larger than 0.5,and the V-t time coefficient(?V)is about three times larger than ?R.Pt nanoarray electrode with a series of hydrophobic gradient differences was prepared.The electrochemical performance test of HER was carried out.It was found that as the mass concentration of PTFE in the hydrophobic treatment increased,the hydrophobicity of electrodes increased,the HER electrochemical performance decreased,and simultaneously the bubble detachment caused a larger current disturbance.The observation of the growth behavior of a single bubble at a constant potential for the hydrophobic electrode revealed that the ?R decreased as the electrode became more hydrophobic.Focusing on the bubble behavior on the surface of the Pt electrode,three kinds of platinum electrodes with different surface morphologies—Pt Flat,Pt on nanoporous gold(NPG-Pt)and Pt nanoarrays respectively.The experimental analysis shows that there is a linear relationship between square root of time and bubble radius for the smooth flat one,demonstrating that,the behavior of gas bubble on solid interface is diffusion controlled at the presence of concentration gradient of dissolved gases in the aqueous electrolyte near to electrode/electrolyte interface.In addition,the value of ?R of the bubble growth curve fitting equation was found that platinum nanoarrays>platinum plane>nanoporous platinum.A new bubble model based on the supersaturated hydrogen component mass transfer is proposed to analyze the value of ?R.