Fabrication of fibrous BiVO4/Bi2S3/MoS2 heterojunction and synergetic enhancement of photocatalytic activity towards pollutant degradation

Synthesis of MoS2/Mg(OH)2/BiVO4 hybrid photocatalyst by ultrasonic homogenization assisted hydrothermal methods and its application as sunlight active photocatalyst for water decontamination

In this work, MoS₂/Mg(OH)₂/BiVO₄ ternary hybrid photocatalyst was synthesized by sonicated precursor mixture to the hydrothermal procedure to generate a highly efficient solar light-induced and simply recyclable photocatalyst. The obtained hybrid was confirmed by the characteristic peaks of MoS₂/Mg(OH)₂/BiVO₄ observed in X-ray diffraction (14.31°/18.62°/28.18°), infrared spectra (465/445/679 cm^-1), ultraviolet-visible spectra (636/683/639 nm) studies, and the band-gap narrowing (2.62/2.44/2.25 eV). The morphological structure of MoS₂ (rod), Mg(OH)₂ (particles), and BiVO₄ (random aggregates) were turned into MoS₂/Mg(OH)₂/BiVO₄ hierarchical nanosheets that coexisted with particles. The photodegradation experiments of the photocatalysts were assessed by using Congo Red (CR), Malachite Green (MG) and Textile Industry Effluent (TIE) as the model pollutant under direct sunlight. The photocatalytic efficiency of the hybrids was noticeably 2.1 to 2.3 times higher than that of the individual components. Photocurrent response test indicate that MoS₂/Mg(OH)₂/BiVO₄ ternary hybrid nanocomposites photocatalysts had a more effective electron/hole pair separation than individual and binary composite photocatalysts. The mechanism of photodegradation of MoS₂/Mg(OH)₂/BiVO₄ternary hybrid photocatalysts was investigated and discussed.

Recent Progress in Photocatalytic Removal of Environmental Pollution Hazards in Water Using Nanostructured Materials

Water pollution has become a critical issue because of the Industrial Revolution, growing populations, extended droughts, and climate change. Therefore, advanced technologies for wastewater remediation are urgently needed. Water contaminants are generally classified as microorganisms and inorganic/organic pollutants. Inorganic pollutants are toxic and some of them are carcinogenic materials, such as cadmium, arsenic, chromium, cadmium, lead, and mercury. Organic pollutants are contained in various materials, including organic dyes, pesticides, personal care products, detergents, and industrial organic wastes. Nanostructured materials could be potential candidates for photocatalytic reduction and for photodegradation of organic pollutants in wastewater since they have unique physical, chemical, and optical properties. Enhanced photocatalytic performance of nanostructured semiconductors can be achieved using numerous techniques; nanostructured semiconductors can be doped with different species, transition metals, noble metals or nonmetals, or a luminescence agent. Furthermore, another technique to enhance the photocatalytic performance of nanostructured semiconductors is doping with materials that have a narrow band gap. Nanostructure modification, surface engineering, and heterojunction/homojunction production all take significant time and effort. In this review, I report on the synthesis and characterization of nanostructured materials, and we discuss the photocatalytic performance of these nanostructured materials in reducing environmental pollutants.

In-situ construction of step-scheme MoS2/Bi4O5Br2 heterojunction with improved photocatalytic activity of Rhodamine B degradation and disinfection

In this paper, a novel Step-scheme MoS₂/Bi₄O₅Br₂ heterojunction was fabricated through the in-situ mechanical agitation method and the photocatalytic activity of that was examined by the photocatalytic degradation Rhodamine B (RhB) and inactivation of E.coli under visible light irradiation (λ > 420 nm). The Step-scheme MoS₂/Bi₄O₅Br₂ heterojunctions displayed the enhanced photocatalytic ability compared to pure Bi₄O₅Br₂ and MoS₂ and the MoS₂/Bi₄O₅Br₂-3% (MS/BOB-3) heterojunction exhibited the strongest photocatalytic activity which can completely inactivate the 1 × 10⁷ cfu/mL with 180 min and degrade RhB (10 mg/L) with 24 min visible light irradiation, respectively. The photocatalytic mechanism of the MoS₂/Bi₄O₅Br₂ heterojunction is was attributed to the generated active species (h⁺, ·O₂^- and ·OH) which can effectively destroy RhB molecular and cell-membrane of bacterial as demonstrated by multiple techniques such as LC-MS and fluorescence stain. Additionally, characterization results disclosed that the transfer pathway of charge carriers of constructed MoS₂/Bi₄O₅Br₂ heterojunction followed the Step-scheme channel, which not only facilitated the separation and migration of the photo-generated charge carriers, but also improved the light absorption ability of the samples and resulting in the promoted photocatalytic performance of MoS₂/Bi₄O₅Br₂ heterojunction. This work paves a new idea to develop novel bismuth oxyhalide-based photocatalytic system for wastewater purification.

In-situ construction of superhydrophilic crystalline Ni3S2@amorphous VOx heterostructure nanorod arrays for hydrogen evolution reaction with industry-compatible current density. Dalton Trans 2022;51:7234-7240. [DOI: 10.1039/d2dt00157h]

The synergistic effect of high active surface/interface and optimized electronic structure of electrocatalysts is of great significance to improve the performance of hydrogen evolution reaction. Herein, a superhydrophilic core@shell heterostructure...

Bi2S3 quantum dots in situ grown on MoS2 nanoflowers: An efficient electron-rich interface for photoelectrochemical N2 reduction

Photoelectrocatalysis is considered a green, environmentally friendly, sustainable technology for NH₃ synthesis. However, the low efficiency of ammonia synthesis is currently the primary problem in photoelectrochemical nitrogen reduction reactions (PEC NRR). Herein, a nanocomposite BQD/MS developed through the in-situ growth of Bi₂S₃ quantum dots (BQD) on MoS₂ (MS) nanoflowers was demonstrated as an efficient PEC NRR catalyst. Experimental results showed that the strong interaction between BQD and MS modulated the interfacial charge distribution and increased the electron density on the MS side. Meanwhile, the excellent structure of BQD/MS promoted the effective migration of photogenerated electrons from excited BQD to the MS surface. The electron-rich MS reaction interface was conducive to cleaving the stable NN bond and improving the N₂ reduction performance. As a result, the prepared BQD/15MS photocathode obtained an excellent Faradaic efficiency of 33.2% and an NH₃ yield of 18.5 μg h^-1 mg^-1, which was about three times that of bare MS.

Selective Electrochemical Sensing Platform Based on the Synergy between Carbon Black and Single-Crystalline Bismuth Sulfide for Rapid Analysis of Antipyretic Drugs

Nanomaterials are of significant interest in acetaminophen (APAP) detection in pharmaceutical samples. Herein, a carbon black/single-crystalline rodlike bismuth sulfide (CB/Bi₂S₃) composite prepared by an ultrasonic method is reported and utilized for the rapid analysis of APAP. The highly oriented edge reactive sites of the CB/Bi₂S₃ composite promoted synergy and good electrochemical sensing performance with a fast electron transfer rate and low overpotential (0.35 V). Therefore, a CB/Bi₂S₃ composite-modified glassy carbon electrode (GCE) was applied to the selective determination of APAP by the voltammetric technique. The CB/Bi₂S₃ composite-modified electrode showed the lowest limit of detection of APAP (1.9 nM) with excellent sensitivity. The proposed CB/Bi₂S₃/GCE platform exhibited high selectivity, excellent stability (87.15%), and reproducibility. Also, the CB/Bi₂S₃/GCE sensor was then successfully used to analyze an APAP pharmaceutical sample and exhibited satisfactory outcomes. Therefore, the CB/Bi₂S₃-modified GCE sensor platform would be a low-cost and robust GCE electrode material for APAP detection.