Ga based Sillenite-TiO2 composite for efficient sunlight induced photo reduction of Cr (VI) and photo degradation of ampicillin

This work reports the design and development of an efficient sillenite based visible light photoactive Bi₂₄Ga₂O₃₉-TiO₂ (BGT) heterostructure. Structural and morphological studies based on X-ray diffraction (XRD) and high-resolution scanning electron microscopy (HRSEM) confirm the formation of combined phase as well the overall morphology of composite BGT. Additionally, X-ray photoelectron spectroscopy (XPS) results confirm the presence of Bi³⁺, Ga³⁺, Ti⁴⁺ & O^2-. The composite exhibits a shift in the absorbance edge towards visible region of electromagnetic spectrum when compared to that of TiO₂. Suitable band edge positions in the composite facilitate the formation of type-1 heterojunction enhancing visible light photocatalytic property. The photocatalytic activity is evident from photo reduction of Cr (VI) (95% reduction in 180 min). The composite also plays an improved and effective role in the degradation of persistent drug ampicillin-cloxacillin (AMC) with a rate constant of 0.02 min^-1. Photocatalytic experiments conducted at different pH values showed higher performance at lower pH ∼3. Trapping experiments performed on the sample confirm the role of holes as the main active species during photocatalysis. Appreciable recyclability of BGT composite was noted with respect to AMC drug degradation.

Synergistic effects of multi-active sites in silver modified Bi°-BiVO4 toward efficient reduction of aromatic nitrobenzene

In this work, we report on the preparation of silver nanoparticles modified bismuth/bismuth vanadate (Bi°-BiVO₄) catalyst with multi-active sites toward efficient reduction of aromatic nitrobenzene, aiming to tailor the synergistic effects of multi-active sites and specify the underlying catalytic mechanism. The as-prepared catalysts were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray and X-ray photoelectron spectroscopy. It is observed that Ag nanoparticles with diameter of ˜30 nm were anchored evenly on the surface of rod-shaped BiVO₄, which offered multi-active sites to contact with the reactants effectively and transfer interfacial electron to 4-nitrophenol (4-NP) rapidly. The activity factor k of Ag/Bi°-BiVO₄ for 4-NP reduction is estimated to ˜3933.4 min^-1 g^-1, which is much higher than that obtained from pristine BiVO₄ catalyst, Bi° and noble metal Ag nanoparticles. According to the experimental results, the reaction mechanism and reaction path of 4-NP reduction for BiVO₄, Bi and Ag were studied through the density functional theory (DFT) theoretical calculation, which suggested that they exhibit synergistic catalytic effect in the reaction process. This work may provide a feasible foundation for the mechanism research of semiconductor reduction to 4-nitrophenol.

Review on nanoscale Bi-based photocatalysts

Nanoscale Bi-based photocatalysts are promising candidates for visible-light-driven photocatalytic environmental remediation and energy conversion. However, the performance of bulk bismuthal semiconductors is unsatisfactory. Increasing efforts have been focused on enhancing the performance of this photocatalyst family. Many studies have reported on component adjustment, morphology control, heterojunction construction, and surface modification. Herein, recent topics in these fields, including doping, changing stoichiometry, solid solutions, ultrathin nanosheets, hierarchical and hollow architectures, conventional heterojunctions, direct Z-scheme junctions, and surface modification of conductive materials and semiconductors, are reviewed. The progress in the enhancement mechanism involving light absorption, band structure tailoring, and separation and utilization of excited carriers, is also introduced. The challenges and tendencies in the studies of nanoscale Bi-based photocatalysts are discussed and summarized.

A highly selective conversion of toxic nitrobenzene to nontoxic aminobenzene by Cu2O/Bi/Bi2MoO6

Cu₂O/Bi/Bi₂MoO₆, a ternary catalyst, was expertly prepared using an in situ catalytic reduction reaction.

Novel construction technique, structure and photocatalysis of Y2O2CN2 nanofibers and nanobelts

Pure trigonal phase Y₂O₂CN₂ nanofibers and nanobelts have been successfully prepared by electrospinning in conjunction with cyanamidation technology. Y₂O₂CN₂ nanofibers and nanobelts possess excellent and stable photocatalytic performance.

Electrospinning construction of Bi2WO6/RGO composite nanofibers with significantly enhanced photocatalytic water splitting activity

Bi₂WO₆/reduced graphene oxide composite nanofibers possessing significantly enhanced photocatalytic water splitting activity have been successfully fabricated.