It has been challenging for Fe(Ⅲ)regeneration in Fe-based photocatalysts for continuous peroxydisulfate(PDS)activation due to the lower ability to reduce Fe(Ⅲ).In this work,Fe-doped ultrathin VO_(2)(Fe-VO_(2))nanobelts were synthesized for purifying metronidazole(MNZ)via PDS activation.As an efficient Fentonlike catalyst for PDS activation,2 wt%Fe-doped VO_(2)can remove 98%of MNZ within 40 min and exhibits impressive recyclability.The synergistic effect of Fe-VO_(2)and Fe(Ⅲ)activated PDS boosted the photocatalytic performance.Moreover,SO_(4)•^(−),h+,O_(2)•^(−),^(1)O_(2),and•OH were the main reactive radicals.The effects of initial MNZ concentration,Fe-VO_(2),PDS dosage,and various anions/cations on MNZ removal by the Fe-VO_(2)/PDS/Vis system were studied.The intermediates of MNZ degradation and possible pathways were determined by density function theory(DFT)calculations and HPLC-MS.This study provided a sustainable technology using Fe-doped ultrathin VO_(2)nanobelts for photocatalytic PDS activation and decontamination of pharmaceutical wastewater.
Semiconductor photocatalysis holds significant promise for addressing dye-pollution in water.However,the efficiency of photocatalytic water purification is constrained by the weak light absorption capacity and low active site distribution of photocatalysts.Utilizing a bottom-up approach,carbon-doped TiO_(x)(C-TiO_(x))nanosheets with high concentrations of Ti^(3+)active sites were fabricated by etching the Al element in Ti_(3)Ai C_(2)with H_(2)O_(2).Experimental evidence demonstrates that the optimal C-TiO_(x)nanosheets exhibit high activity for the photocatalytic degradation of methylene blue,achieving a degradation rate of 100%within 50 min.The introduction of carbon into the C-TiO_(x)nanosheets induces a red shift in the absorption edge,boosting the migration of photo-generated charge carriers.Moreover,there is a significant correlation between the concentration of Ti^(3+)active sites and the density of oxygen vacancies in the C-TiO_(x)nanosheets,which synergistically influence the photocatalytic degradation performance of MB dye wastewater.
Perfluoroalkyl substances(PFASs)are typical persistent organic pollutants,and their removal is urgently required but challenging.Photocatalysis has shown potential in PFASs degradation due to the redox capabilities of photoinduced charge carriers in photocatalysts.Herein,hexagonal ZnIn_(2)S_(4)(ZIS)nanosheets were synthesized by a one-pot oil bath method and were well characterized by a series of techniques.In the degradation of sodium p-perfluorous nonenoxybenzenesulfonate(OBS),one kind of representative PFASs,the assynthesized ZIS showed activity superior to P25 TiO_(2) under both simulated sunlight and visible-light irradiation.The good photocatalytic performance was attributed to the enhanced light absorption and facilitated charge separation.The pH conditions were found crucial in the photocatalytic process by influencing the OBS adsorption on the ZIS surface.Photogenerated e−and h+were the main active species involved in OBS degradation in the ZIS system.This work confirmed the feasibility and could provide mechanistic insights into the degradation and defluorination of PFASs by visible-light photocatalysis.
It is a challenging task to efficiently convert deleterious hydrogen sulfide(H_(2)S)into less harmful products such as SO_(4)^(2-)species.In an effort to address such issue,a step-scheme(S-scheme)heterojunction photocatalyst has been built by concatenating TiO_(2)(P25)and ultrathin Bi_(4)O_(5)Br_(2)into TiO_(2)/Bi_(4)O_(5)Br_(2)(namely,x-TB-y:x and y denote the molar ratio of TiO_(2):Bi_(4)O_(5)Br_(2)and pH value for solution-based synthesis,respectively)via in-situ hydrothermal method.The S-scheme charge transfer pathway in TB is confirmed by electron spin resonance and band structure analysis while experimental data and density functional theory calculations suggest the formation of an internal electric field to facilitate the separation and transfer of photoinduced charge carriers.Accordingly,the optimized heterojunction photocatalyst,i.e.,5-TB-9,showcases significantly high(>99%)removal efficiency against 10 ppm H_(2)S in a 17 L chamber within 12 minutes(removal kinetic rate r:0.7 mmol·h^(-1)·g^(-1),specific clean air delivery rate SCADR:5554 L·h^(-1)·g^(-1),quantum yield QY:3.24 E-3 molecules·photon^(-1),and space-time yield STY:3.24 E-3 molecules·photon^(-1)·mg^(-1)).Combined analysis of in-situ diffuse reflectance infrared Fourier transform adsorption spectra and gas chromatography-mass spectrometry allows to evaluate the mechanisms leading to the complete degradation of H_(2)S(i.e.,into SO_(4)^(2-)without forming any intermediate species).This work demonstrates the promising remediation potential of an S-scheme TiO_(2)/Bi_(4)O_(5)Br_(2)photocatalyst against hazardous H_(2)S gas for sustainable environmental remediation.
Baofei HaoYounes AhmadiJan SzulejkoTianhao ZhangZhansheng LuKi-Hyun Kim
For environmental applications,it is crucial to rationally design and synthesize photocatalysts with positive exciton splitting and interfacial charge transfer.Here,a novel Agbridged dual Z-scheme Ag/g-C_(3)N_(4)/CoNi-LDH plasmonic heterojunction was successfully synthesized using a simple method,with the goal of overcoming the common drawbacks of traditional photocatalysts such as weak photoresponsivity,rapid combination of photogenerated carriers,and unstable structure.These materials were characterized by XRD,FT-IR,SEM,TEM UV-Vis/DRS,and XPS to verify the structure and stability of the heterostructure.The pristine LDH,g-C_(3)N_(4),and Ag/g-C_(3)N_(4)/CoNi-LDH composite were investigated as photocatalysts for water remediation,an environmentally motivated process.Specifically,the photocatalytic degradation of tetracycline was studied as a model reaction.The performance of the supports and composite catalyst were determined by evaluating both the degradation and adsorption phenomenon.The influence of several experimental parameters such as catalyst loading,pH,and tetracycline concentrationwere evaluated.The current study provides important data for water treatment and similar environmental protection applications.
Razieh FazaeliHamid AliyanDarrin RichesonYuning Li
