Design And Synthesis Of The Bismuth-based Photocatalysts And Study On The Mechanism Of Antibiotic Degradation Coupling With Simultaneous Resource Recovery

During the treatment of antibiotic wastewater,various technologies have been proposed to realize its harmless treatment.However,it is estimated that wastewater treatment in China will produce 54.14 million tons of carbon dioxide equivalent(CO2e)in 2016,accounting for 1.71%of total emissions,and this figure will rise to 2.95%by 2030.Therefore,converting the secondary carbon pollution generated in the removal process of antibiotic into useful fuels or value-added chemicals is a promising way to reduce carbon source waste.However,the simultaneous recycling reaction of antibiotic degradation involves the simultaneous oxidation reaction and reduction reaction.Due to the bottleneck problems such as large competition of oxidation/reduction active sites,low efficiency of synchronous reaction and poor selectivity of CO2 reduction,the synchronous recycling of antibiotic degradation is difficult to achieve.Given the above problems,we carried out related research:1)A synthetic strategy for accurately regulating the ratio of(0 0 1)/(1 1 0)co-exposed facets of BiVO4 was invented,and the controllable adjustment of the facets and morpology of BiVO4 was proved through characterization.In addition,photoelectrochemical measurements and in situ Kelvin probe force microscopy were used to suggest the face-dependent charge transfer and migration directions of BiVO4 catalysts.2)BiOBr/BiVO4 photocatalyst rich in surface oxygen vacancy was synthesized by one-pot method,which achieved 86.12%removal rate of carbamazepine under 4 hours of light irradiation and highly selective conversion of CO2 to 10.23 μmol·g-1 CO.Through experimental tests and DFT calculations,it is proved that the oxygen vacancy in the BiOBr/BiVO4 composite induces the internal directional charge transfer from BiOBr to BiVO4,and the active site constructed by the oxygen vacancy and its adjacent surface hydroxyl group can effectively adsorb and activate CO2.3)Pt/BiVO4 catalyst with facet-selective active site was designed,99.55%of diclofenac sodium was removed and CO2 was reduced to 18.14 mmol·g-1·L-1 polycarbonate product C2H5OH(selectivity>90%)after 5 hours’visible light irradiation via the regulation of microenvironment.Through kinds of characterization and theoretical calculation analysis,it was confirmed that the surface electron-rich microenvironment induced by selective deposition of Pt nanoparticles on the(0 0 1)plane of BiVO4 promoted the deep oxidation of pollutants.The microenvironment ehanced CO3-·constructed at the catalyst optimizes the energy barrier of the key step of C-C coupling and realizes the highly selective production of ethanol.4)Mo-BiVO4 catalyst doped with heteroatom was synthesized by in-situ microwave hydrothermal method.Under 4 hours’ visible light irradiation,the Mo-BiVO4 catalyst could achieve 99.18%degradation of bisphenol A and selectively produce 38.01 μmol·g-1 CO by photocatalytic coupling advanced oxidation.The experimental characterization and DFT calculation proved that the Mo atom tends to replace the V site of the tetrahedron in the Mo-BiVO4 catalyst.Meanwhile,unsaturated electrons in the Mo atom adsorb proton H to form a large number of surface-bridged hydroxy-OHB.Finally,the structure-activity relationship between the modification of the Mo-BiVO4 catalyst and its photocatalytic coupling of advanced oxidation degradation of bisphenol A and photoreduction of CO2 to selectively obtain CO was revealed.