Ag-decorated 3D flower-like Bi_(2)MoO_(6)/rGO with boosted photocatalytic performance for removal of organic pollutants

A series of unique 3D flower-like Bi_(2)MoO_(6)(BMO)/reduced graphene oxide(rGO)heterostructured composites decorated with varying amounts of Ag nanoparticles(NPs)were fabricated.Their morphological characteristics,structural features,energy band structures and photoelectrochemical properties were systematically studied.All the Ag/BMO/rGO ternary composites(AgBGy;y=1%,2%and 3%)demonstrated greater photocatalytic activity towards efficient removal of our selected organic models[methyl orange(MO),rhodamine B(RhB)and phenol],as compared with the BMO/rGO binary composites(BG-x;x=0.25,2,4 and 5).Particularly,AgBG-2%,which was synthesized with the addition of 2 wt% rGO and 2 wt%Ag in BMO,possessed superior photocatalytic activity.The fitted rate constants(k)for the photocatalytic degradation of RhB,MO and phenol using AgBG-2% were estimated to be 0.0286,0.0301 and 0.0165 min^(-1),respectively,which were over one order of magnitude greater than those obtained using pure BMO.Several factors may contribute to the observed enhancement,including greater specific surface area,enhanced light absorption,promoted spatial separation of electronhole(e^(-)-h^(+))pairs and their suppressed recombination,especially benefiting from the synergistic effects among BMO,rGO and Ag NPs.Our work suggests that the rational design of BMO/rGO/Ag ternary composite was an effective strategy to boost the photocatalytic activity of the resulting catalyst towards the highly efficient removal of organic pollutants from water.

Constructing Z-schemeβ-Bi_(2)O_(3)/ZrO_(2)heterojunctions with 3D mesoporous SiO_(2)nanospheres for efficient antibiotic remediation via synergistic adsorption and photocatalysis

A series of Z-schemeβ-Bi_(2)O_(3)/ZrO_(2)hetero-junction composites containing three-dimensional(3D)mesoporous silica nanospheres(MSNs)were synthesized as efficient catalysts for antibiotic remediation.The obtained MSN/β-Bi_(2)O_(3)/ZrO_(2)ternary composites possess novel lamellar cross structure,which is well constructed byβ-Bi_(2)O_(3)nanosheets,3D MSNs,and ZrO_(2)nanoparticles.The optimal sample BZS-2(Bi∶Zr∶Si=1∶0.4∶0.33)shows an adsorptive-photocatalytic removal efficiency of 92.7%towards levofloxacin(LVF)and a total organic carbon(TOC)removal efficiency of 60.0%under simu-lated solar light irradiation for 100 min.BZS-2 can also remove 90.1%and 91.2%of tetracycline hydrochloride(TC)and oxytetracycline hydrochloride(OTC),respectively,and themaximum adsorptioncapacityof TCover BZS-2is almost 10 times that of-BiO.Theimprovement ofphotocatalytic activitycan bemainly attributed to the enhanced visible-light adsorption capacity and more efficientseparationof photogenerated electron-hole pairs.A possible Z-scheme photocatalytic mechanism of p BiO/ZrOheterojunctions based on valence band offset(AEvBo)andconduction band offset(EcBo)isproposed.This study provides an efficient way to construct novel mesoporous ternary photocatalyst with increased accessible surface area and active sites for treatment of antibiotics by synergistic adsorption and photocatalysis.