Study On The Novel Photocatalysts For The Conversion Of Methane And Its Mechanism Of Action

With the high-speed development of the modern world,the huge consumption of oil and coa,not only led to the gross pollution of the social environment,but also the traditional energy storage is also facing to dry up.At the same time,as a kind of greenhouse gas,methane has a nonnegligible influence on the earth’s ecological environment.Develop the new way of methane transforming into higher value or smaller environmental hazards product can not only improve the utilization value of methane but also can weaken the influence of greenhouse effect on the ecological environment.Relative to thermal catalytic technology,semiconductor photocatalytic technology can not only react under atmospheric pressure conditions but also can get high yield of target product.After decades of research,the photocatalytic conversion of methane has achieved some achievements,due to the defect of catalytic technology and methane high stability,development of new types of photocatalyst and the new reaction system to improving the conversion efficiency of methane has fundamental significance.This article adopts the method of precipitation-calcination to preparing gallium oxide and zinc oxide with different crystalline phases,precious metal is loaded on zinc oxide by illumination.Using XRD,DRS,SEM,TEM,BET,XPS to reveal the characteristic of catalyst.Through the photocatalystic reaction in self-assembly reactor,the performance for the methane photocatalytic conversion of photocatalyst is evaluated.This research has found out these main conclusion and novel results:1.Under nearly normal temperature and pressure,the photocatalytic conversion of methane could takes place coupling and oxidation reactions at the same time.2.The highest rate of methane conversion over β-Ga2O3 was 3.24 μ l/(gh),the apparent quantum efficiency reached 2.76%,the hydrocarbon selectivity of product was 6.41%,the selectivity of CO was 27.5%,the selectivity of CO2 is supreme.The average consumption rate of methane over α-Ga2O3 was 2.973 μl/(gh),the apparent quantum efficiency was 1.99%,the hydrocarbon selectivity of product was 21.4%,the selectivity of CO increased to 58.6%,the selectivity of CO2 decreases to 20%.3.Under simulated sunlight,the 10%Ag-ZnO-350 ℃ photocatalyst that we prepared through the precipitation-calcining-light deposition method can makes the average methane reaction rate increased to 15.1 μl/(gh),the selectivity of hydrocarbon production increased to 42.8%,the catalyst with the highest under 254 nm light quantum efficiency was 7.84%.4.Through the analysis of active species,we put forward the possible photocatalytic mechanism between methane and oxygen.