Construction Of Photocatalytic Water Splitting Device And Oxygen Production Performance Evalution Of Mono-and Binuclear Ruthenium Complexes

Research of renewable energy is a priority area for short-and long-term industrial promotion.Among them,the photolysis of water to produce hydrogen and oxygen is considered to be one of the most promising methods.Hydrogen production by solar photocatalysis is a challenging issue that has received much attention in recent years.Since this research topic has the potential to provide clean and renewable energy on a large scale,which can be achieved mainly through direct decomposition of water into hydrogen and oxygen.Most oxo-ruthenium complexes,cationic ruthenium species and nitrogen-containing ruthenium complexes have excellent photophysical properties and can be used as photocatalysts.The research to realize photolysis water is mainly divided into two aspects:the construction of photocatalytic devices and the preparation of photocatalysts.This paper constructs a more advanced photocatalytic hydrogen and oxygen production device,and synthesizes mono-and bi-nuclear ruthenium compounds with certain catalytic ability.The ruthenium complexes are employed as photocatalysts to test the oxygen production performance of the device.The main work are as follows:1.Existing visible light catalytic devices are limited by problems such as large heat generation of the light source,difficulty in heat dissipation,and gas collection.Most of the adopted photocatalytic devices involve liquid-discharge and gas-collecting devices.However,there is no guarantee for the accuracy and stability of the experimental data.In response to these problems,we introduced a photocatalytic reactor that is easy to dissipate heat and enables online analysis of the generated gas.The photocatalytic device can provide a vacuum-tight environment,which is isolated from the outside world,eliminating the interference of external gas,and ensuring the air-tightness and stability of the device.Gas is collected online,as long as the gas is not adsorbed by the glass,it can be detected by gas chromatography to ensure the accuracy of the data.For the reason,the device can be widely used in the experimental research on the photolysis of water to produce hydrogen,oxygen,and CO₂ reduction to produce methanol,methane and other small organic molecules at room temperature.2.It has been found that ruthenium complexes are widely used in photocatalytic hydrogen production,oxygen production,CO₂ reduction,etc.due to their unique redox and photochemical properties.This chapter uses this as an entry point to successfully synthesize a series of mononuclear ruthenium complexes of dialkyldithiocarbamate（DTC）and o-phenanthroline（phen）containing different substituents[（phen）₂Ru（Me₂NCS₂）]（PF₆）（1）,[（phen）₂Ru（Et₂NCS₂）]（PF₆）（2）,[（phen）₂Ru（ⁿPr₂NCS₂）]（PF₆）（3）,[（phen）₂Ru（ⁿBu₂NCS₂）]（PF₆）（4）and one bi-nuclear ruthenium complex withμ-O oxygen bridge[（bpy）₂Ru（μ-O）（μ-Me N=NMe）Ru（bpy）₂]（Cl O₄）₂（5）.The ruthenium complexes are characterized by UV-Vis,IR,and ¹HNMR spectroscopies.Moreover,their electrochemical properties are investigated.Molecular structures of three ruthenium complexes 1～3 and 5 are further confirmed by single-crystal X-ray diffraction analysis.3.Using a 300W xenon lamp as a visible light source（using a 420nm filter）,the system analyzed different factors such as photocatalysts,the amount of catalyst,light intensity,the amount of sacrificial agent,p H value,the content of photosensitizer,and solvent.The study showed that under the following conditions:2mg（0.18 mmol%）binuclear ruthenium complex[（bpy）₂Ru（μ-O）（μ-Me N=NMe）Ru（bpy）₂]（Cl O₄）₂（5）used as the catalyst,15mg（2.3mmol%）of[Ru（bpy）₃]Cl₂ used as the photosensitizer,15mg（6.3mmol%）Na₂S₂O₈ acted as electron sacrificial agent,p H=9,the volume ratio of acetonitrile and water being of 1:1,under 250W light intensity,the system can obtain the maximum oxygen production（TON=96）.Based on the results,the oxygen production mechanism of three-component photolysis water was proposed.