Search

Photoelectrochemical (PEC) systems are inefficient, probably due to charge carrier mobility, recombination rate, and solar light absorption. Fabricating semiconductor-metal sulfide nanocomposites and nanostructured materials can improve the absorption of solar radiation, electron–hole separation, transport, and hydrogen (H2) and oxygen generation to resolve the world's energy dilemma. The vanadium-doped (V) layered graphitic carbon nitride (g-CN)/MoS2 (MS) nanocomposite was synthesized employing two-step solvent evaporation and thermal condensation. This multilayer V-doped g-CN/MS nanocomposite broke down methyl red dye in 60 min under sunlight. Due to visible light absorption, the V-doped g-CN-MS nanostructure degrades the dye by 97.84%. We found that at 3.0 wt % V-doped g-CN/MS coated on TiO2 nanorods. The catalyst nanocomposites displayed a high photocurrent density of 23.72 mA cm–2 and a H2 production rate of 4477 mol h–1 cm–2. Additionally, the microstructure, optical absorption behavior, and electrical conductivity were all shown to contribute to these impressive PEC characteristics. The V-modified g-CN/MS nanocomposite structures are effective and regulated PEC catalysts, and this study suggests ways to improve PEC water splitting and degradation. [ABSTRACT FROM AUTHOR]

A superficial, one step thermal polycondensation method has been employed for the manifestation of graphene like graphitic carbon nitride (g-C3N4) catalyst. The as synthesized g-C3N4 was well characterized by SEM and EDAX analysis, XRD, ATR-IR, FTIR, Fluorescence spectroscopy, Raman spectroscopy and UV–Visible spectroscopy which provide structural, morphological assemblage relating to the structure of g-C3N4. The g-C3N4 showed that an outstanding photochemical stability, morphology, conductive carbon framework and superior photocatalytic activity. The band gap value of g-C3N4 is 2.34 eV determined using Tauc plot. Due to low band gap (2.33 eV) and unique morphology which provides high separation and migration ability of the photogenerated charges, the g-C3N4 shows enhanced photocatalytic activity for the removal of many organic dyes such as Rhodamine B (RhB), Crystal Violet (CV), Methylene Blue (MB), Methyl Orange (MO), Naphthol Orange (NO) and a phenol derivative, p-Nitrophenol (p-NP). Among them, RhB dye was degraded almost 81 % at 90 min under sunlight irradiation in presence g-C3N4 while other dyes and p-NP was degraded at lower rate. From the experimental data, it was found that MO and p-NP degradation rate was least. The rate constant for degradation of Rh B is 1.1 × 10−2 min−1. Therefore, g-C3N4 can be used as an efficient photocatalyst for waste water treatment by the removal of such organic pollutants.

This research deals with the synthesis of copoly(methylvinyl)(dimethyl)siloxanes by the copolycondensation of dimethyldiethoxy- and methylvinyldimethoxysilane in an active medium, followed by thermal condensation in a vacuum. We achieved a range of copolymers exhibiting finely tuned molecular weights spanning between 1500 and 20,000 with regulated functional methylvinylsiloxane units. Analysis of the microstructure showed that the copolymerization predominantly formed products demonstrating a random distribution of units (R~1). However, an increase in the content of vinyl-containing monomers increases the R parameter, indicating an enhanced tendency towards alternating linkages within the copolymer matrix. [ABSTRACT FROM AUTHOR]

This research deals with the synthesis of copoly(methylvinyl)(dimethyl)siloxanes by the copolycondensation of dimethyldiethoxy- and methylvinyldimethoxysilane in an active medium, followed by thermal condensation in a vacuum. We achieved a range of copolymers exhibiting finely tuned molecular weights spanning between 1500 and 20,000 with regulated functional methylvinylsiloxane units. Analysis of the microstructure showed that the copolymerization predominantly formed products demonstrating a random distribution of units (R~1). However, an increase in the content of vinyl-containing monomers increases the R parameter, indicating an enhanced tendency towards alternating linkages within the copolymer matrix.

Having access to safe drinking water is one of the 17 sustainable development goals defined by the United Nations (UN). However, many settlements around the globe have limited access to drinkable water due to non-anthropogenic pollution of the water sources. One of those pollutants is fluoride, which can induce major health problems. In this manuscript, we report on a post synthetic functionalization of metal organic frameworks for the sensing of fluoride in water. The proposed thermal condensation methodology allows for a high yield of functionalization using few steps, reducing reagent costs and generating minimal by-products. We identified a Rhodamine B functionalized Al-BDC-NH2 metal organic framework as one particularly suitable for fluoride detection in water. [ABSTRACT FROM AUTHOR]

A superficial, one step thermal polycondensation method has been employed for the manifestation of graphene like graphitic carbon nitride (g-C 3 N 4 ) catalyst. The as synthesized g-C 3 N 4 was well characterized by SEM and EDAX analysis, XRD, ATR-IR, FTIR, Fluorescence spectroscopy, Raman spectroscopy and UV-Visible spectroscopy which provide structural, morphological assemblage relating to the structure of g-C 3 N 4 . The g-C 3 N 4 showed that an outstanding photochemical stability, morphology, conductive carbon framework and superior photocatalytic activity. The band gap value of g-C 3 N 4 is 2.34 eV determined using Tauc plot. Due to low band gap (2.33 eV) and unique morphology which provides high separation and migration ability of the photogenerated charges, the g-C 3 N 4 shows enhanced photocatalytic activity for the removal of many organic dyes such as Rhodamine B (RhB), Crystal Violet (CV), Methylene Blue (MB), Methyl Orange (MO), Naphthol Orange (NO) and a phenol derivative, p -Nitrophenol (p-NP). Among them, RhB dye was degraded almost 81 % at 90 min under sunlight irradiation in presence g-C 3 N 4 while other dyes and p-NP was degraded at lower rate. From the experimental data, it was found that MO and p-NP degradation rate was least. The rate constant for degradation of Rh B is 1.1 × 10 -2 min -1 . Therefore, g-C 3 N 4 can be used as an efficient photocatalyst for waste water treatment by the removal of such organic pollutants., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr. Suranjan Sikdar reports administrative support was provided by University of North Bengal. Afroja Banu reports a relationship with University of North Bengal that includes: non-financial support. N A has patent NA pending to NA. Not Applicable If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

Having access to safe drinking water is one of the 17 sustainable development goals defined by the United Nations (UN). However, many settlements around the globe have limited access to drinkable water due to non-anthropogenic pollution of the water sources. One of those pollutants is fluoride, which can induce major health problems. In this manuscript, we report on a post synthetic functionalization of metal organic frameworks for the sensing of fluoride in water. The proposed thermal condensation methodology allows for a high yield of functionalization using few steps, reducing reagent costs and generating minimal by-products. We identified a Rhodamine B functionalized Al-BDC-NH2 metal organic framework as one particularly suitable for fluoride detection in water.

Electrochemical energy conversion and storage technologies involving controlled catalysis provide a sustainable way to handle the intermittency of renewable energy sources, as well as to produce green chemicals/fuels in an ecofriendly manner. Core to such technology is the development of efficient electrocatalysts with high activity, selectivity, long-term stability, and low costs. Here, two-dimensional (2D) carbonaceous materials have emerged as promising contenders for advancing the chemistry in electrocatalysis. We review the emerging 2D carbonaceous materials for electrocatalysis, focusing primarily on the fine engineering of active structures through thermal condensation, where the design, fabrication, and mechanism investigations over different types of active moieties are summarized. Interestingly, all the recipes creating two-dimensionality on the carbon products also give specific electrocatalytic functionality, where the special mechanisms favoring 2D growth and their consequences on materials functionality are analyzed. Particularly, the structure-activity relationship between specific heteroatoms/defects and catalytic performance within 2D metal-free electrocatalysts is highlighted. Further, major challenges and opportunities for the practical implementation of 2D carbonaceous materials in electrocatalysis are summarized with the purpose to give future material design guidelines for attaining desirable catalytic structures.

The frequent use of methylene blue (MB) and other organic dyes pose serious environmental concerns subjected to their resistance towards traditional degradation procedures. Therefore, it is important to develop efficient degradation treatments to degrade such dyes. We report a facile thermal condensation methodology to synthesize graphitic nitride (GN) and its derived polyimides by using three different dianhydrides. The obtained results from physicochemical characterization; FTIR, XRD, XPS, and BET/BJH confirmed the formation of GN and its derived polyimides. The synthesized photocatalyst materials were tested for MB degradation under light irradiation for 60 min. Interestingly, the superior photocatalytic performance (96% MB degradation efficiency) despite of decreased surface area of polyimide, GN-FDA (6.78 m2 g−1) has been attributed to its relatively improved degree of crystallinity, greater HOMO-LUMO charge separation, high quaternary nitrogen content, and appropriate porosity. This study can be concluded as follows; firstly the π conjugated polyimides surprisingly undergo significant shrinkage in surface area probably due to π-π interactions. Secondly, derived polyimides exhibited essential features of photocatalytic materials viz greater HOMO-LUMO charge separation evidenced by DFT studies, improved hydrophilicity, appropriate surface area/ porosity, and surface nitrogen functionalities that improve their degradation efficiency. Quantum mechanical calculations reveal that modification of GN results in improved electronic properties and enhanced dye degradation attributed to modified charge transfer. This work may open new opportunities to develop efficient metal-free photocatalysts based on GN that are a significant contribution in designing suitable photocatalyst materials for degradation of other organic dyes/ contaminants. [Display omitted] • Graphitic Nitride (GN) based polyimides were synthesized by thermal condensation of derived GN with different dianhydrides. • The polyimides were characterized by physicochemical techniques; FTIR, XRD, BET/BJH, XPS, SEM, UV-vis and PL spectroscopy. • The synthesized polyimide; GN-FDA exhibited highest degradation efficiency (96 %) for the degradation of methylene blue dye. • Quantum mechanical calculations suggested improved electronic properties and modified charge transfer in the polyimides. • The improved physicochemical properties and modified charge transfer resulted in high degradation efficiency of polyimide. [ABSTRACT FROM AUTHOR]