Fabrication of g-C_(3)N_(4) nanosheet/Bi_(5)O_(7)Br/NH_(2)-MIL-88B(Fe)nanocomposites:Double S-scheme photocatalysts with impressive performance for the removal of antibiotics under visible light

Novel graphitic carbon nitride(g-C_(3)N_(4))nanosheet/Bi_(5)O_(7)Br/NH_(2)-MIL-88B(Fe)photocatalysts(denoted as GCN-NSh/Bi_(5)O_(7)Br/FeMOF,in which MOF is metal–organic framework)with double S-scheme heterojunctions were synthesized by a facile solvothermal route.The resultant materials were examined by X-ray photoelectron spectrometer(XPS),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDX),transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM),photoluminescence spectroscopy(PL),Fourier transform infrared spectroscopy(FT-IR),UV-Vis diffuse reflection spectroscopy(UV-vis DRS),photocurrent density,electrochemical impedance spectroscopy(EIS),and Brunauer–Emmett–Teller(BET)analyses.After the integration of Fe-MOF with GCN-NSh/Bi_(5)O_(7)Br,the removal constant of tetracycline over the optimal GCN-NSh/Bi_(5)O_(7)Br/Fe-MOF(15wt%)nanocomposite was promoted 33 times compared with that of the pristine GCN.The GCN-NSh/Bi_(5)O_(7)Br/Fe-MOF(15wt%)nanocomposite showed superior photoactivity to azithromycin,metronidazole,and cephalexin removal that was 36.4,20.2,and 14.6 times higher than that of pure GCN,respectively.Radical quenching tests showed that·O_(2)-and h+mainly contributed to the elimination reaction.In addition,the nanocomposite maintained excellent activity after 4 successive cycles.Based on the developed n–n heterojunctions among n-GCN-NSh,n-Bi_(5)O_(7)Br,and n-Fe-MOF semiconductors,the double S-scheme charge transfer mechanism was proposed for the destruction of the selected antibiotics.

Perovskite-type lanthanum ferrite based photocatalysts:Preparation,properties,and applications

Clean energy and a sustainable environment are grand challenges that the world is facing which can be addressed by converting solar energy into transportable and storable fuels(chemical fuel).The main scientific and technological challenges for efficient solar energy conversion,energy storage,and environmental applications are the stability,durability,and performance of low-cost functional materials.Among different nanomaterials,perovskite type LaFeO_(3)has been extensively investigated as a photocatalyst due to its abundance,high stability,compositional and structural fexibility,high electrocatalytic activity,efficient sunlight absorption,and tunable band gap and band edges.Hence,it is urgent to write a comprehensive review to highlight the trend,challenges,and prospects of LaFeO_(3)in the field of photocatalytic solar energy conversion and environment purification.This critical review summarizes the history and basic principles of photocatalysis.Further,it reviews in detail the LaFeO_(3),applications,shortcomings,and activity enhancement strategies including the design of nanostructures,elemental doping,and heterojunctions construction such as Type-I,Type-II,Z-Type,and uncommon heterojunctions.Besides,the optical and electronic properties,charge carriers separation,electron transport phenomenon and alignment of the band gaps in LaFeO_(3)-based heterostructures are comprehensively discussed.

Spin regulation on(Co,Ni)Se_(2)/C@FeOOH hollow nanocage accelerates water oxidation

Spin engineering is recognized as a promising strategy that modulates the association between d‐orbital electrons and the oxygenated species,and enhances the catalytic kinetics.However,few efforts have been made to clarify whether spin engineering could make a considerable enhancement for electrocatalytic water oxidation.Herein,we report the spin engineering of a nanocage‐structured(Co,Ni)Se_(2)/C@FeOOH,that showed significant oxygen evolution reaction(OER)activity.Magnetization measurement presented that the(Co,Ni)Se_(2)/C@FeOOH sample possesses higher polarization spin number(μb=6.966μB/f.u.)compared with that of the(Co,Ni)Se_(2)/C sample(μb=6.398μB/f.u.),for which the enlarged spin polarization number favors the adsorption and desorption energy of the intermediate oxygenated species,as confirmed by surface valance band spectra.Consequently,the(Co,Ni)Se_(2)/C@FeOOH affords remarkable OER product with a low overpotential of 241 mV at a current of 10 mA cm^(-2) and small Tafel slope of 44 mV dec^(-1) in 1.0 mol/L KOH alkaline solution,significantly surpassing the parent(Co,Ni)Se_(2)/C catalyst.This work will trigger a solid step for the design of highly‐efficient OER electrocatalysts.

Novel ternary g-C_3N_4/Fe_3O_4/MnWO_4 nanocomposites: Synthesis,characterization, and visible-light photocatalytic performance for environmental purposes

The g-C3 N4/Fe3 O4/MnWO4 nanocomposites were prepared by a refluxing-calcination procedure. Visiblelight-induced photocatalytic experiments showed that the g-C3 N4/Fe3 O4/MnWO4（10%） nanocomposite has excellent ability to degrade a range of contaminants including rhodamine B, methylene blue, methyl orange, and fuchsine, which is about 7, 10, 25, and 31 times of the g-C3 N4 photocatalyst, respectively.Reactive species trapping experiments revealed that superoxide anion radicals play major role in the photodegradation reaction of rhodamine B（RhB）. After the treatment process, the utilized photocatalyst was magnetically recovered and reused with negligible loss in the photocatalytic activity, which is vital in the photocatalytic processes. Finally, a mechanism was proposed for the enhanced interfacial carrier separation and transfer and the improved photocatalytic performance.

Fabrication of novel ZnO/MnWO_4 nanocomposites with p-n heterojunction: Visible-light-induced photocatalysts with substantially improved activity and durability

We report, for the first time, binary ZnO/MnW04 nanocomposites with p-n heterojunction fabricated by a simple ultrasonic-calcination route. The phase structure, morphology, and optical along with tex- tural properties were comprehensively characterized. The photocatalytic performance was studied via degradations of rhodamine B, methyl blue and methyl orange （RhB, MB, MO）, and fuchsine pollutants under visible-light illumination. The ZnO/MnW04 nanocomposites exhibited better photocatalytic per-formance than their single components and the nanocomposite with 30 wt% MnW04 showed the highest activity. Photocatalytic performance of this nanocomposite is 22.5, 17.7, 26.8, and 23.9 times higher than that of the ZnO sample in degradations of RhB, MB, MO, and fuchsine dyes, respectively. The improved photocatalytic performance was ascribed to the formation ofp-n heterojunction between ZnO and MnW04 with high charge separation efficiency as well as strong visible-light absorption ability. The possible mechanism for the improved photocatalytic performance was proposed. This study revealed that the novel ZnO/MnW04 p-n heterojunction can act as a promising visible-light-active photocatalyst for environmental applications.