Application Of Natural And Artificial Synthetic Material Doped With Rare Earth Elements In Photocatalytic Water Splitting

The exploitation of fossil energy brings serious environmental pollution and ecological damage.Hydrogen is a clean energy source with high energy density.Photocatalytic decomposition of water to produce hydrogen is an eco-friendly hydrogen production strategy.In photolysis water,designing and synthesizing photocatalysts that can effectively utilize sunlight is an important way to improve photocatalytic hydrogen production efficiency.However,most of semiconductor catalysts have a wide band gap and only can respond to ultraviolet light,which limits their utilization of sunlight.Due to the unfilled 4f and5d electronic configurations,rare earth elements have rich electronic energy levels and long lifetime excited states.There are many electronic transition channels,so they can generate a variety of radiation absorption and emission,and become a wide range of luminescent and laser materials.In this paper,we mainly use the light conversion performance of rare earth conversion material and natural ore?Ce,La?[CO₃]F materials and the catalytic activity of rare earth ions to achieve photocatalytic hydrogen production in the whole spectral range.This article is divided into four chapters:The first chapter is the introduction part,which mainly reviews the current research progress in the field of photocatalysis,especially the light-emitting principle and synthesis method and its application in the field of photocatalysis of rare earth materials such as rare earth upconversion luminescent materials,rare earth long afterglow materials and rare earth natural ore materials,etc.And briefly introduced the significance of the topic and the main research content.In the second chapter,the hydrogen production performance of long afterglow/upconversion composites excited by near-infrared light is studied and the mechanism of hydrogen production is clarified.In this research,Y₂O₂S:Eu³⁺,Mg²⁺,Ti⁴⁺/YVO₄:Yb³⁺,Er³⁺persistence/upconversion luminescent materials were assembled by converting YVO₄:Yb³⁺,Er³⁺upconversion luminescent material and Y₂O₂S:Eu³⁺,Mg²⁺,Ti⁴⁺persistence luminescence material.The upconversion material is used to convert near-infrared light into ultraviolet light and visible light,thereby exciting long afterglow materials,and at the same time,utilizing long-lived characteristics of carriers generated by long afterglow materials,thereby achieving long-term continuous hydrogen production under near-infrared light excitation.In the third chapter,the research on the photocatalytic hydrogen production by using natural materials directly as a photocatalyst is carried out for the problems of complicated synthetic steps,high energy consumption and high cost of synthetic materials.?Ce,La?[CO₃]F is a natural ore that does not require us to lose energy to synthesize photocatalysts,so that the value of photolytic water will be greatly enhanced.However,the disadvantage is that the forbidden band width is large,and only ultraviolet light and full light can be used.We want to obtain a better photocatalytic effect by using the calcination treatment.The high temperature calcination treatment produces oxygen vacancies,which reduces the forbidden band width of?Ce,La?[CO₃]F,and solves the problem of narrow spectral response,thereby improving photocatalytic effect of the?Ce,La?[CO₃]F to achieve hydrogen production under visible light.The fourth chapter summarizes and forecasts the full text briefly.