Ternary Ag/Ag3PO_(4)/MIL-125-NH2 Z-scheme heterojunction for boosted photocatalytic Cr(Ⅵ)cleanup under visible light

摘要

The binary Ag3 P04/MIL-125-NH2(AMN-X)composites were synthesized through ion exchange-solution method,and the ternary Ag/Ag3 PO_(4)/MIL-125-NH2(AAMN-X)Z-scheme heterojunctions were prepared via the photo chemical reduction deposition strategy.The photocatalytic hexavalent chromium(Cr(VI))sequestration over AMN-X and AAMN-X were investigated under visible light.AAMN-120 accomplished superior reduction performance due to that Ag nanoparticles(NPs)act as electrons transfer bridge to enhance the separation efficiency of photogenerated e-h+pairs,in which the reaction rates(k.value)were 2.77 and 124.2 fold higher than those of individual MIL-125-NH2 and Ag3 PO_(4),respectively.The influences of different pH values,small organic acids and coexisting ions on the photocatalytic perfo rmance of AAMN-120 were also investigated.In addition,the AAMN-120 heterojunction expressed great reusability and stability in cycling experiments.The mechanism of photocatalytic Cr(VI)was investigated and verified through photoluminescence(PL),electrochemistry,electron spin resonance(ESR),active species capture,and Pt element deposition experiments.