Preparation And Performance Of Novel Fe₂O₃-Bi₂O₃-Bi₂S₃ And Fe₂O₃-MoS₂-CdS Photoelectrocatalysts

Developing environmentally friendly treatment technology becomes increasingly essential to resolve the environmental pollution problems.Photoelectrocatalysis?PEC?technique provides a "green" method using solar light for elimination of pollution and producing energy.Herein,we focus on the fabrication and performance of novel visible light driven photoelectrocatalysts.Fe₂O₃-Bi₂O₃-Bi₂S₃ photoelectrocatalytic film was fabricated by electrodeposition,calcination and hydrothermal reaction and characterized by XRD,XPS and SEM.Results indicated that Bi₂O₃ and Bi₂S₃ were loaded on the Fe₂O₃,which significantly changed the morphology of Fe₂O₃.The photocurrent density of Fe₂O₃-Bi₂O₃-Bi₂S₃ composite increases by 8 times relative to pure Fe₂O₃ at 0.45 V vs.Ag/AgCl in 0.1 M NaOH aqueous solution under visible light irradiation.Compared with Fe₂O₃-Bi₂O₃ and Fe₂O₃ films,the Fe₂O₃-Bi₂O₃-Bi₂S₃ electrode exhibits the smallest charge transfer resistance,highest IPCE value and slowest recombination rate.Thus,the transfer and separation efficiency of electron-hole pairs as well as photocatalytic activity of Fe₂O₃-Bi₂O₃-Bi₂S₃ film were enhanced.The PEC activity of Fe₂O₃-Bi₂O₃-Bi₂S₃ electrode was evaluated by the degradation of phenol under visible light irradiation.Among the tested films,Fe₂O₃-Bi₂O₃-Bi₂S₃ film exhibited the highest PEC activity for phenol degradation.Then,the prepared Fe₂O₃-Bi₂O₃-Bi₂S₃ films were used for degradation of phenol in photoelectrochemical system in comparison with that in photochemical and electrochemical system.The effects of applied potential,initial pH value,initial concentration and trapping agent type on degradation efficiency of phenol were investigated systematically.The PEC reaction rate of phenol increased with the enhancement of the applied potential.Good degradation efficiency was achieved in the acid or neutral solution.The photogenerated holes and hydroxyl radicals were considered as main active species by adding different trapping agents.Moreover,good stability and activity were observed in cyclic runs.Fe₂O₃-MoS₂-CdS film was fabricated by electrodeposition,calcination,hydrothermal reaction and chemical bath deposition.The photocurrent density of Fe₂O₃-MoS₂-CdS composite increases by 40 times relative to pure Fe₂O₃ at 0.45 V vs.Ag/AgCl in 0.1 M NaOH aqueous solution under visible light irradiation.In addition,the Fe₂O₃-MoS₂-CdS electrode exhibits the smallest charge transfer resistance,highest IPCE value and slowest recombination rate.Therefore,the photocatalytic activity was enhanced.The as-prepared Fe₂O₃-MoS₂-CdS films were used as the photoanodes to test the PEC activity by the degradation of phenol.The degradation efficiency of phenol using Fe₂O₃-MoS₂-CdS films in the PEC system was the highest,compared with that in photochemical and electrochemical system.Among the tested films,Fe₂O₃-MoS₂-CdS film exhibited the highest PEC activity for phenol degradation.The highest degradation efficiency?90.47%?,rate constant?0.0076 min-1?and electrochemical enhancement value?97.37%?were observed at 2.5 V.Good degradation efficiencies were achieved in the acid or neutral solution.By adding different trapping agents,the superoxide radicals and hydroxyl radicals were considered as main active species.Moreover,good stability and activity were observed in cyclic runs.