Shape tailoring of AgBr microstructures: effect of the cations of different bromide sources and applied surfactants

Investigations regarding AgBr-based photocatalysts came to the center of attention due to their high photosensitivity. The present research focuses on the systematic investigation regarding the effect of different alkali metal cation radii and surfactants/capping agents applied during the synthesis of silver-halides. Their morpho-structural and optical properties were determined via X-ray diffractometry, diffuse reflectance spectroscopy, scanning electron microscopy, infrared spectroscopy, and contact angle measurements. The semiconductors' photocatalytic activities were investigated using methyl orange as the model contaminant under visible light irradiation. The correlation between the photocatalytic activity and the obtained optical and morpho-structural properties was analyzed using generalized linear models. Moreover, since the (photo)stability of Ag-based photoactive materials is a crucial issue, the stability of catalysts was also investigated after the degradation process. It was concluded that (i) the photoactivity of the samples could be fine-tuned using different precursors and surfactants, (ii) the as-obtained AgBr microcrystals were transformed into other Ag-containing composites during/after the degradation, and (iii) elemental bromide did not form during the degradation process. Thus, the proposed mechanisms in the literature (for the degradation of MO using AgBr) must be reconsidered.

Systematic investigation of the effect of different alkali metal cation radii and shape-tailoring agents applied during the synthesis of AgBr-based photocatalysts.

Synthesis of BiOI@(BiO)2CO3 facet coupling heterostructures toward efficient visible-light photocatalytic properties

BiOI@(BiO)₂CO₃ facet coupling heterostructures were synthesized, and showed much higher photocatalytic activity than BiOI and (BiO)₂CO₃ under visible light.

Advanced nanoarchitectures of silver/silver compound composites for photochemical reactions

Silver/silver compound (SSC) composites have received much attention as a type of potential materials in photochemical reactions due to their high efficiency, facile syntheses and availability of raw materials. This article reviews the state-of-the-art progress on the advanced nanoarchitectures of SSC composites. We begin with a survey on the general synthetic strategies for SSC composites, and then step into relatively detailed methods for size and morphology tunable two-component and more delicate multi-component SSC nanostructures. In addition, the electronic structure-related mechanisms of such materials and the recent studies on their stability are summarized. This review also highlights some perspectives on challenges related to the SSC composites and the possible research in the future.

Facile synthesis of one dimensional AgBr@Ag nanostructures and their visible light photocatalytic properties

In this work, we successfully prepared one dimensional (1D) AgBr@Ag nanostructures in high yield by a facile wet chemical method, and the plausible growth mechanism was discussed. The synthesis of as-prepared AgBr@Ag nanostructure is a dissolution and recrystallization process, and the PVP and DMSO have a synergistic and competitive effect on the preparation of 1D AgBr@Ag products. Moreover, the AgBr@Ag nanorods exhibit excellent photocatalytic activities under visible light illumination, which may be attributed to their large surface area as well as superior charge separation and transfer efficiency compared to AgBr@Ag particles.

Porous FeOx/BiVO4-deltaS0.08: highly efficient photocatalysts for the degradation of methylene blue under visible-light illumination

Porous S-doped bismuth vanadate with an olive-like morphology and its supported iron oxide (y wt.% FeOx/BiVO4-deltaS0.08, y = 0.06, 0.76, and 1.40) photocatalysts were fabricated using the dodecylamine-assisted alcohol-hydrothermal and incipient wetness impregnation methods, respectively. It is shown that the y wt.% FeOx/BiVO4-deltaS0.08 photocatalysts contained a monoclinic scheetlite BiVO4 phase with a porous olive-like morphology, a surface area of 8.8-9.2 m2/g, and a bandgap energy of 2.38-2.42 eV. There was co-presence of surface Bi5+, Bi3+, V5+, V3+, Fe3+, and Fe2+ species in y wt.% FeOx/BiVO4-deltaS0.08. The 1.40 wt.% FeOx/BiVO4-deltaS0.08 sample performed the best for Methylene Blue degradation under visible-light illumination. The photocatalytic mechanism was also discussed. We believe that the sulfur and FeOx co-doping, higher oxygen adspecies concentration, and lower bandgap energy were responsible for the excellent visible-light-driven catalytic activity of 1.40 wt.% FeOx/BiVO4-deltaS0.08.

High-performance visible-light-driven plasmonic photocatalysts Ag/AgCl with controlled size and shape using graphene oxide as capping agent and catalyst promoter

We report herein that Ag/AgCl-based plasmonic photocatalysts with controlled size and shape could be easily formulated by a one-pot approach via a precipitation reaction between AgNO3 or Ag(NH3)2NO3 and NaCl. It is found that near-spherical and cube-like Ag/AgCl nanoarchitectures of 500 nm could be fabricated at lower and higher temperature, respectively. Fascinatingly, when graphene oxide (GO) nanosheets are introduced into the synthesis medium, the size of the formulated near-spherical and cube-like nanostructures, Ag/AgCl/GO, could be 2.5 and 5 times reduced to ca. 200 and 100 nm, respectively, when AgNO3 and Ag(NH3)2NO3 are employed as the silver source. The series of our Ag/AgCl-based nanostructures could be used as visible-light-driven plasmonic photocatalysts for the photodegradation of methyl orange pollutants, wherein the cube-like Ag/AgCl/GO nanoarchitectures of 100 nm display the highest catalytic activity. It is disclosed that the synergistic effect of size, shape, and GO nanosheets plays an important role for their boosted photocatalytic performances. The investigation reveals that GO nanosheets work not only as a capping agent for a controllable fabrication of Ag/AgCl nanostructures, but also as catalyst promoter during the photocatalytic performances, leading to an enhanced catalytic activity. Our unique GO-assisted method likely paves a facile avenue and initiates new opportunities for the exploration of GO-hybridized high-performance catalysts.