Synthetic Process And Performance Study Of Conductive ZnO Thin Film And Phosphomolybdate Film For Electrocatalytic Hydrogen Evolution Reaction

The study on ZnO dates back to1930s, but not until the past few years, the excellentproperties of ZnO including wide and direct band gap (3.37eV under room temperature), highexciting banding energy (60meV) and good bio-compatibility are valued and applied to devicessuch as transparent electrode and TFT, ultraviolet detector, photodiode, piezoelectric devices,semiconductor spin devices, biosensor and so on.In this thesis, we first discuss the process of preparation of ZnO thin films on common glasssubstrate by sol-gel method, and the influence of the doping concentration, the number of layersand the annealing temperature to the crystalline state, growth orientation, microstructure andconductivity of the film. The results of the experiments show that, in the temperature range whichcommon glass could suffer,1.5%doping concentration,20layers and set550℃as theannealing temperature is the best condition to get the most even, compact and transparent film,and the film also has better c-axis orientation and lower resistance.The fossil energy crisis and environmental pollution may be solved by the rapid developmentof renewable energy sources. As an inexhaustible energy sources, photovoltaic power also has abottleneck that the generated electricity could not be stored easily and produced whenever needed.But there is an ideal storage for photovoltaic power--hydrogen energy has many advantages suchas: light weight, high heat value, it comes from the splitting of water and becomes water afteroxidation. It has been more than half a century that people make utilization of hydrogen as thestorage of photovoltaic power by photoelectrocatalysis water splitting, the recent search resultsshowed that several molecular solid state (containing Mo, Co element) compounds catalyze watersplitting in very positive onset-potential and small over-potential, these compounds are muchmore cheaper than noble metal catalysis and the multiphase compounds do not run off easily.The second part of this thesis focus on three types of polyoxometalate (containing Mo and P),we study their electrodeposition process and get the electrochemistry modification electrode withfilm. Then we use the modified electrode and select the proper over-potential to perform constantpotential electrolysis and achieve high Faraday efficiency. We also use the equipment includingSEM, AFM, XPS and Raman Spectrum to characterize the film and analysis the results.The phase changes during the crystal growth influence the properties and functions of thecrystal directly. Since to some materials whose melting point is lower than phase transformation point and cannot be obtained by the traditional melting top-seeded pulling technique, melt rapidcooling method could be a proper way to obtain the assigned crystal. The last part of this thesissimulates the process of iron melt crystal growth by molecular dynamics, and discusses thegeneral laws during this process. This work can contribute to the synthesis of ZnO film andPOMs.