The Influence Of Doping Method On The Photoelectrocatalytic And Photocatalytic Properties Of Ag-TiO₂-Reduced Graphene Electrode

Photocatalytic fuel cell?PFC?technology was based on the development of photocatalytic technology.PFC can achieve the transformation of refractory biodegrade pollutants into chemical energy.It can also produce electrical energy from waste water at the same time.Therefore,PFC is one of the most promising ways to implement sustainable development strategy and realize energy efficient utilization and recycling.However,in the operation of photocatalytic fuel cells,there are many factors that restrict the photocatalytic degradation efficiency and power output:low visible light utilization efficiency,low carrier separation rate and slow electron transmission rate.In this paper,Ag-doped titanium dioxide composite reduced graphene was used as the photocatalytic fuel cell anode to explore the mechanism of the above problems.The photocatalytic fuel cell anode prepared in this study is based on titanium dioxide.Firstly,Ag-TiO₂ nanomaterials with visible light catalytic capacity were prepared by doping Ag with hydrothermal method.Taking 20 ppm tetracycline as the target pollutant,the degradation efficiency of Ag-TiO₂ relative to TiO₂ under visible light was improved by 26.1%.Ag doping did not change the adsorption sites on the surface of titanium dioxide,and the adsorption capacity was 60±3%.The mechanism of photocatalytic degradation of tetracycline by Ag-TiO₂ was studied.Reduced graphene can effectively increase electron transfer on the surface of TiO₂.The migration modes were layered composite and mixed composite,i.e.,0.125-1.0%reduced graphene was loaded on Ag-TiO₂ in layered and mixed methods for study.The morphology,light absorption,surface functional groups,electrochemical impedance and Mott-Schottky curves of the two composite electrodes were measured.The electrochemical characteristics of the electrode were analyzed by degradation tetracycline experiment and free radical scavenging experiment.In order to explore the difference and principle of electron transport method,two kinds of composite electrodes were compared in the operation of photoelectric catalysis and photocatalytic fuel cell.First of all,photoelectric catalysis were studied by applying 0.5 V external voltage,anode potential and cyclic voltammetry curve measurement.The results were consistent with the hypothesis of electron accumulation caused by graphene in mixed composite electrodes.The results of radicals scavenging experiments on tetracycline degradation showed that the main active species produced by the two electrodes were different.The main active species produced by the layered composite electrode LG-6 were h⁺and·OH,while the mixed composite electrode MG-0.25 mainly produced·O₂^-.Then,through the operation of photocatalytic fuel cells,the advantages of layered composite electrode electron transport were highlighted.The filling factors of layered and mixed composite electrodes were 0.208 and 0.148 respectively.