Yagna Prakash Bhoi

Bio: Yagna Prakash Bhoi is an academic researcher from National Institute of Technology, Rourkela. The author has contributed to research in topics: Photocatalysis & Nanocomposite. The author has an hindex of 11, co-authored 16 publications receiving 390 citations. Previous affiliations of Yagna Prakash Bhoi include University of Science and Technology of China.

Photocatalytic degradation of alachlor using type-II CuS/BiFeO3 heterojunctions as novel photocatalyst under visible light irradiation

Abstract: In this study, a sustainable visible light promoted photocatalytic route has been developed for mineralization of alachlor pesticide using CuS/BiFeO3 heterojunction materials. The heterojunctions were synthesized by a two-step process and characterized using XRD, FESEM, HRTEM, XPS, FTIR, UV–Vis-DRS and PL techniques. Morphologically, the heterojunction materials consist of BiFeO3 nanoplates with high aspect ratio and CuS nanorods. The intimate contact between the two phases was ascertained from the HRTEM study. Optical property study suggested that these materials show excellent absorption in visible region with superior charge carrier separation characteristics compared to the individual components. The transient photocurrent measurement and I-V plots revealed high mobility of the excitons across grain boundary due to heterojunction formation. The band positions of the two components were aligned favourably for a cyclic movement of electrons and holes resulting in a type-II heterojunctions. The CuS/BiFeO3 materials efficiently catalyse the mineralization of alachlor pesticide under visible light illumination achieving >95% degradation within 60 min. The mechanism of alachlor degradation over the catalyst surface was elucidated using GCMS and radical scavenger experiments. The attractive features of the developed photocatalytic method are the use of renewable energy, low cost, high efficiency, stability and recyclability of the catalyst material.

Combustion synthesis, characterization and photocatalytic application of CuS/Bi4Ti3O12 p-n heterojunction materials towards efficient degradation of 2-methyl-4-chlorophenoxyacetic acid herbicide under visible light

Abstract: In this study, a series of CuS/Bi4Ti3O12 p-n heterojunction materials were synthesized by a two-step process. Initially, the Aurivillius phase Bi4Ti3O12 (BT) was synthesized by a facile combustion route using urea as a fuel. The Bi4Ti3O12 was subsequently modified by deposition of CuS (5–20 wt%) using a hydrothermal route to prepare the heterojunction materials. The methods of synthesis and calcination temperature were important factors which influenced the morphology, particle size and phase purity of Bi4Ti3O12 material. Phase pure BT nanoplates with planar dimension of 150–200 nm and thickness between 50 and 70 nm were obtained at a calcination temperature of 600 °C. Pure CuS prepared by hydrothermal method, contained hierarchical microspheres with diameter in the range of 1.2–1.6 μm. The heterostructure materials exhibited hierarchical flower like structure consisting of ultrathin CuS nanosheets and BT-nanoflakes. HRTEM and microstructural study revealed microscopic close interaction between the two phases. The optical and electrical measurement study suggested significant improvement in visible light absorption (400–800 nm) and charge carrier separation due to heterojunction formation. The CuS/Bi4Ti3O12 materials showed excellent photocatalytic activity for aqueous phase degradation of 2-methyl-4-chlorophenoxyacetic acid (MCPA) herbicide under visible light (>95% degradation in 3 h). The rate constant for CuS/Bi4Ti3O12 materials was 4.5 times higher than the pure BT material towards MCPA degradation. The OH and O2 – radicals have been identified as the reactive species, the formation of which was confirmed by spectrometric method using terephthalic acid and nitroblue tetrazolium as molecular probes. The mechanism of MCPA degradation over the photocatalyst surface has also been elucidated using LC-ESI-MS, TOC and scavenger experiments.

Morphology controlled synthesis and photocatalytic study of novel CuS-Bi2O2CO3 heterojunction system for chlorpyrifos degradation under visible light illumination

Abstract: In this study, Bi2O2CO3 (BSC) nanoplates with high aspect ratio and hierarchical nanostructures were prepared by hydrothermal technique using urea/hexamethylenetetramine as hydrolysing agent and KCl as additive in different solvent systems. The relative molar proportion of urea and KCl was crucial for phase purity as well as thickness and planar dimension of the BSC plates. The BSC nanoplates were used as substrates to prepare CuS-Bi2O2CO3 (CuS/BSC) direct z-scheme heterojunction systems. The heterojunction materials were characterized by FESEM, HRTEM, XRD, PL, FTIR and UV–Vis-DRS techniques. The presence of crystalline tetragonal BSC and hexagonal covellite CuS phase was inferred from XRD study. Morphologically, the CuS/BSC material contained CuS nanorods and BSC nanoplates. HRTEM study suggested microscopic close contact between the CuS nanorods and BSC nanoplates. Optical property study revealed improvement in visible light absorption and enhanced separation of excitons. The CuS/BSC materials were used as photocatalyst for chlorpyrifos pesticide degradation under visible light irradiation. The heterojunction materials were highly active achieving >95% degradation within 3 h of reaction. The pathway and mechanism of CP degradation was elucidated using GCMS and radical scavenger experiments.

α-NiS/Bi2O3 Nanocomposites for Enhanced Photocatalytic Degradation of Tramadol

Abstract: In this study, a series of α-NiS/Bi2O3 composite nanomaterials were prepared and evaluated as efficient photocatalyst for degradation of tramadol under visible light. Two polymorphs of Bi2O3, namel...

Visible light-assisted photocatalytic mineralization of diuron pesticide using novel type II CuS/Bi2W2O9 heterojunctions with a hierarchical microspherical structure

Abstract: In this study, a series of CuS/Bi2W2O9 type II heterojunction photocatalysts with a hierarchical microspherical structure were prepared by a two-step process involving the combustion synthesis of Bi2W2O9 followed by CuS modification using a hydrothermal method. The heterojunctions were characterized by XRD, XPS, FESEM, TEM, IR, UV-vis-DRS and PL techniques. During synthesis, Cu2+ ions replaced W6+ ions to form Bi2CuxW2−xO9−2x as a nonstoichiometric solid solution phase. Pure Bi2W2O9 exhibited plate-like micron-sized particles. Under hydrothermal treatment, the desegregation of the Bi2W2O9 plates to nanosheets and the concurrent formation of CuS nanorods were noticed leading to their hierarchical reorganisation to microspherical structures. The heterojunction materials exhibited enhanced visible light absorption with an improved charge carrier separation ability. The CuS/Bi2W2O9 heterojunction materials were studied as an efficient photocatalyst for the degradation of diuron pesticide under visible light irradiation achieving 95% mineralization within 3 h. A mechanistic study indicated that the mineralization of diuron occurred in a cascade manner over the catalyst surface involving dechlorination, alkyl oxidation and oxidative ring-opening steps. In this study, a highly efficient visible light active photocatalytic system has been developed for the first time that is a viable alternative to a TiO2-based UV active photocatalyst for the mineralization of diuron pesticide.

Mechanistic insights into photodegradation of organic dyes using heterostructure photocatalysts

Abstract: Due to its low cost, environmentally friendly process, and lack of secondary contamination, the photodegradation of dyes is regarded as a promising technology for industrial wastewater treatment. This technology demonstrates the light-enhanced generation of charge carriers and reactive radicals that non-selectively degrade various organic dyes into water, CO2, and other organic compounds via direct photodegradation or a sensitization-mediated degradation process. The overall efficiency of the photocatalysis system is closely dependent upon operational parameters that govern the adsorption and photodegradation of dye molecules, including the initial dye concentration, pH of the solution, temperature of the reaction medium, and light intensity. Additionally, the charge-carrier properties of the photocatalyst strongly affect the generation of reactive species in the heterogeneous photodegradation and thereby dictate the photodegradation efficiency. Herein, this comprehensive review discusses the pseudo kinetics and mechanisms of the photodegradation reactions. The operational factors affecting the photodegradation of either cationic or anionic dye molecules, as well as the charge-carrier properties of the photocatalyst, are also fully explored. By further analyzing past works to clarify key active species for photodegradation reactions and optimal conditions, this review provides helpful guidelines that can be applied to foster the development of efficient photodegradation systems.

Reduction of Nitro Compounds Using 3d-Non-Noble Metal Catalysts

Abstract: The reduction of nitro compounds to the corresponding amines is one of the most utilized catalytic processes in the fine and bulk chemical industry. The latest development of catalysts with cheap metals like Fe, Co, Ni, and Cu has led to their tremendous achievements over the last years prompting their greater application as “standard” catalysts. In this review, we will comprehensively discuss the use of homogeneous and heterogeneous catalysts based on non-noble 3d-metals for the reduction of nitro compounds using various reductants. The different systems will be revised considering both the catalytic performances and synthetic aspects highlighting also their advantages and disadvantages.

Review on Metal Sulphide-based Z-scheme Photocatalysts

Abstract: Semiconductor‐based Z‐scheme heterojunction photocatalysts have received considerable attention for solar energy conversion and environmental purification due to their spatially separated reduction and oxidation sites, effective separation and transportation of photo‐excited charge carriers and strong redox ability. With their wide visible‐light responsive range and high photocatalytic activity, metal sulphide is an important material in developing photocatalysts. This review summarizes and highlights recent research progress in sulphide‐based direct Z‐scheme photocatalysts, followed by analysis on the limitations over all‐solid‐state Z‐scheme photocatalyst. Furthermore, the applications and characterization methods of sulphide‐based direct Z‐scheme photocatalyst are summarized. Finally, the challenges and perspectives of sulphide‐based Z‐scheme photocatalyst are discussed.

One pot synthesis of CdS/BiOBr/Bi2O2CO3: A novel ternary double Z-scheme heterostructure photocatalyst for efficient degradation of atrazine

Abstract: In this study, a simple one-step hydrothermal method was developed for morphology controlled synthesis of CdS/BiOBr/Bi2O2CO3 ternary heterostructure materials. The ternary system contained well dispersed CdS nanoparticles (50–80 nm) anchored over ultrathin BiOBr and Bi2O2CO3 nanoplates with high interfacial contact. A significant enhancement in visible light absorption, prolonged life time decay and improved charge carrier separation and migration property accounted for the excellent photocatalytic activity towards atrazine herbicide degradation (>95% in 30 min). A double Z-scheme electron transfer mechanism was proposed to explain the dramatic increase in photocatalytic activity which was deduced from photoelectrochemical measurements, scavenger and radical ( OH and O2 ‾) trapping experiments. MTT assay study revealed that the photo-catalytically treated atrazine solution showed significant reduction in cytotoxicity. This study provides an effective strategy for facile synthesis of bismuth based ternary heterostructures with potential applications in the field of environmental remediation.

CuInS 2 quantum dots embedded in Bi 2 WO 6 nanoflowers for enhanced visible light photocatalytic removal of contaminants

Abstract: Novel CuInS2 quantum dots (CIS-QDs)/Bi2WO6 3D composites were successfully synthesized through a facile deposition process, followed by low temperature calcination. The ternary p-type CIS-QDs were highly dispersed onto the surface of flower-like n-type Bi2WO6 nanosheets to form p-n heterojunction and simultaneously tune the behaviors of photogenerated charge carriers, resulting in higher photocatalytic efficiencies of toluene degradation and Cr(VI) reduction under visible light irradiation, which are 3.0 and 8.5 times higher than those of Bi2WO6, respectively. The photoelectrochemical investigations indicate that the introduction of CIS-QDs synergistically enhanced the harvesting efficiency of solar energy in the p-n heterojunction system with the internal electric field and reduced transfer barrier of photoinduced charge carriers by forming the unique Bi S bonds between the CIS-QDs and flower-like Bi2WO6.