ZIF-8 Assisted Performance Enhancement Of Weak Photo-reduction Photocatalyst?Bi₄O₅Br₂ And Ag₃PO₄?

Photocatalytic H₂ productions from water splitting and degradation of pollutants over semiconductors under solar irradiation have attracted more and more attention due to its potential as one of efficient,low-cost,and environmentally friendly methods to solve the energy crisis and environmental contamination.Now,the key of photocatalytic technology is the research and development of efficient photocatalysts.A lot of past reports shows,construction of heterojunction photocatalyst can improving the photocatalytic performance by efficiency inhibit the recombination of photoinduced electron and hole.However,the photoinduced electron and hole separation efficiency is high,and the redox capacity of heterojunction photocatalysts decreases.Therefore,the target of heterojunction photocatalyst is to promote the separation efficiency and redox ability of photoinduced electron and hole simultaneously.In this paper,the weak photo-reduction photocatalysts?Bi₄O₅Br₂ and Ag₃PO₄?were choosed as research object,the Bi₄O₅Br₂/ZIF-8 and Ag₃PO₄/ZIF-8 heterojunction photocatalysts with excellent photocatalytic activity and stability were prepared by two-step method.The main contents were focused on the following aspects:?1?Bi₄O₅Br₂/ZIF-8 heterojunction photocatalyst was prepared by fixing weak photo-reduction Bi₄O₅Br₂ nanosheets at the surface of strong reduction ZIF-8,which was used as a carrier.The as-prepared samples were tested by X ray diffraction?XRD?,ultraviolet visible diffuse reflectance spectroscopy?UV-Vis?,X ray photoelectron spectroscopy?XPS?and Fu Liye transform infrared spectroscopy?FTIR?.Photocatalytic activity was evaluated by photocatalytic degradation of methyl orange?MO?and photocatalyst to remove NO under illumination,the results showed that the degradation of methyl orange over Bi₄O₅Br₂/ZIF-8 was achieved at 100%within 60 min,which was much higher than pure Bi₄O₅Br₂ and ZIF-8.After four recycling runs,the degradation of MO with Bi₄O₅Br₂/ZIF-8 could maintain above 90%,which showed good photocatlytic activity and stability.?2?The weak reduction of Ag₃PO₄ was improved by the strong reduction of ZIF-8,which not only enhanced Ag₃PO₄ photocatalytic activity but also improved its stability.The photocatalytic activity was evaluated by photocatalytic degradation RhB and when NO was removed by photocatalyst under light irradiation,Ag₃PO₄/ZIF-8 material exhibited higher photocatalytic activity than pure Ag₃PO₄.Meanwhile,the activity of Ag₃PO₄/ZIF-8?25%?was the highest.The hole and·O₂^-were determined to be the main active species in photodegradation process under light irradiation were captured by active species.And the photocatalytic mechanism was explored depended on the active species during photocatalytic process as well as the results of energy band calculation.