Cocatalyst Surface Modification For Synergistic Enhancement The Photocatalytic Activity Of Bi₂MoO₆-Based Semiconductor Materials

In recent years,semiconductor photocatalysis technology has attracted extensive attention in the fields of environmental remediation and development of new clean energy academic field due to its advantages of economy,high efficiency and green,etc.The construction of visible-light-responsive photocatalysts with wide-spectrum response,high carrier separation efficiency and surface chemical reactions is still a hot research topic in related fields.As an important Aurivillius semiconductor material,Bi₂MoO₆ is a layered composite oxide composed of?Bi₂O₂?²⁺layers and cornual perovskite-type?MoO₄?^2-sheets alternately laminated,with a forbidden band width of about 2.3-2.8 eV.Due to its excellent photocatalytic activity,stability and low cost,Bi₂MoO₆ has become a multifunctional material and has been widely studied at present.However,Bi₂MoO₆-based catalytic materials still have the disadvantages of low utilization rate of visible light and high recombination rate of photogenerated electrons and holes.The above-mentioned defects limit the practical application of Bi₂MoO₆-based photocatalysts.In this paper,a series of surface/interfacial modification are carried out as well as structure and morphology controlling to promote its photocatalytic performance.The combined strategy,such as plasma resonance?SPR?,surface oxygen vacancy?SOVs?and interface electron transfer?IFCT?strategies are applied to improve the separation efficiency of photo-generated electron-hole pairs and broaden the absorption range of visible light,thus improving the catalytic performance of the Bi₂MoO₆-based photocatalysts.The main conclusions of this paper are as follows:?1?Three-dimensional?3D?spherical Bi₂MoO₆?BMO?was synthesized by alcohol-thermal method,and Au NPs were deposited on its surface by chemical reduction method with sodium borohydride as reducing agent,then all-solid Z-type CdS/Au/BMO photocatalyst was synthesized by secondary hydrothermal method.The photodegradation RhB was selected as a probe reaction to evaluate the activity of the obtained photocatalyst and optimize the optimal composite amount of CdS.Based on the systematic characterization and catalytic activity of Z-type CdS/Au/BMO photocatalyst,it is clarified that the excellent photocatalytic performance of Z-type ternary CdS/Au/BMO is mainly attributed to the synergistic effect of CdS and Au NPs.In the Z-scheme CdS/Au/BMO ternary catalytic system,Au NPs,as a solid-state electron medium,provides a channel for electron transport and transfer.Simultaneously,its surface plasmon resonance?SPR?effect broadens the light response range of the catalyst to visible light and inhibits the recombination of photo-generated electron/hole?e^-/h⁺?pairs.The band gap position of CdS/Au/BMO was determined by structure characterization,and the mechanism for the enhancement photocatalytic activity of as-prepared Z-type CdS/Au/BMO photocatalyst was further discussed.?2?The surface oxygen vacancy?SOVs?and Au NPs co-modified BMO photocatalysts were successfully prepared by simple chemical reduction deposition and calcination.The effect of Au deposition and SOVs on photocatalytic performance of BMO composite was discussed.The results show that the co-modification of SOVs and Au NPs can greatly improve the separation efficiency of photo-generated carriers and broaden the visible light response range of BMO,thus improving the activation efficiency of oxygen molecules.Therefore,the co-modification of SOVS and Au NPS has excellent photocatalytic performance for the degradation of azo dyes?RhB,MO?and phenol.?3?Carbon dots?CDs?,Au NPs and SOVs co-modified BMO photocatalyst were successfully prepared by simple chemical reduction deposition and calcination.Phenol was used as a simulated pollutant to evaluate the photocatalytic activity of the photocatalyst,and the optimal compound amount was optimized.The surface/interfacial synergistic regulation mechanism of BMO activity by CDs,SOVs and Au NP was further discussed.