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Oxygen-containing porous CN hollow nanotubes were engineered by facile thermal polycondensation of oxalic acid-assisted supramolecular aggregates and revealed superior photocatalytic hydrogen production.

A visible light driven 1D/2D-NiMoO4/BiOI nanocomposite photocatalyst was constructed by single step solvothermal method. Here, various composition of NiMoO4/BiOI nanocomposites were prepared by loading different amounts of NiMoO4 (1, 2, 3 wt %) to the BiOI. Among the as-prepared photocatalysts, 1 wt % of NiMoO4 on BiOI (NMBI-1) showed superior photocatalytic activity (92.7 %) under visible light irradiation. On analysis, the optimized NMBI-1 exhibited a lower bandgap energy value of 1.64 eV and also found to show around 2 and 3.7-times higher degradation ability for the removal of MB than the pure NiMoO4 and BiOI respectively. In addition, the optimized NMBI-1 nanocomposite photocatalyst exhibited excellent photostability and recyclability properties. The charge carriers on the interface of the NiMoO4 and BiOI enabled the easy transfer via the newly formed heterojunction, thereby increasing the photocatalytic performance. Additionally, the radical scavengers such as h+ and .OH were found to be the major species in the removal of MB under visible light illumination. Therefore, the 1D/2D-NiMoO4/BiOI nanocomposite photocatalyst materials could possibly be considered for the wastewater remediation processes.

We designed a CeO2−x photocatalyst under the influence of low-frequency ultrasonic waves to generate surface oxygen vacancies for efficient photocatalytic performance.

Although solar-driven hydrogen production and recalcitrant pollutant degradation are appealing technologies, the photocatalytic efficiency for most reactions is limited by insufficient visible-light harvesting ability and restricted charge transfer pathways. To tackle these obstacles, we designed novel photocatalyst Fe2O3/CuxO/TiO2(B) nanofibers (namely, CFTNF-y) via an in situ photodeposition strategy. The effects of the CuxO nanoparticle concentration on TiO2(B) nanofibers (CTNF-x) were investigated, and the optimized catalyst was compared to other synthesized catalysts via a chemical reduction strategy (CTNF-x (NS)). The formation of Fe2O3/CuxO nanoparticles on the TiO2(B) nanofiber (TNF) surface in CFTNF-y nanocomposites was confirmed by HAADF-STEM, elemental mapping, XRF, XPS, XANES and EXAFS results. The CFTNF-y nanocomposites demonstrated a significantly enhanced photocatalytic hydrogen production activity of 65.82 μmol g−1 h−1 under UV-visible light irradiation, which was 12-fold higher than that of pristine TNF. Moreover, the CFTNF-y nanocomposites exhibited a photocatalytic trimethoprim (TMP, a model antibiotic contaminant) removal rate of 0.1 mM g−1 min−1. These excellent photocatalytic performances can be attributed to the uniform distribution of size-controlled Fe2O3/CuxO nanoparticles on the TNF surface, improved light-harvesting ability in the visible region and a remarkable charge carrier separation/transfer rate realized via a dual-Z-scheme heterojunction mediated by an interfacial electric field. This assertion is supported by morphology analysis, ERDT/CBB by RDB-PAS, radical trapping experiments, and photoelectrochemical studies. Moreover, a plausible TMP photodegradation pathway over CFTNF-y nanocomposites is proposed based on LC-MS/MS analysis. The present work highlights a novel approach for the development of a dual-Z-scheme photocatalyst with interfacial charge transfer for achieving efficient photocatalytic performance.

Polyethylene terephthalate (PET) is a nonbiodegradable and multi-functional plastic commodity that produces a significant amount of polyester (PES) textile waste. The management of PET solid waste is a global concern in many developing countries. Chemical recycling and material recovery from PES wastes can rebuild a circular economy in the textile sectors. The main objective of the present research is to enhance the chemical depolymerization of PES's textile wastes through microwave-induced catalytic aminolysis and glycolysis catalysed by Ag-doped ZnO nanoparticles. Catalysts are synthesised by the sol-gel method and characterised using X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), ultraviolet spectroscopy (UV-Vis), field emission scanning microscope (SEM-EDX), and transmission electron microscope (TEM). These parameters included the PET to catalyst ratio, microwave power, time, temperature, and catalyst recycling studies. The catalyst was discovered to be more stable and could be recycled up to six times without losing its activity. Microwave heating is typically faster than conventional heating techniques in terms of reaction time, PET conversion, product yield, and purity. In the aminolysis of PET, the effects of several factors on the conversion of PET and the yield of bis (2-hydroxy ethylene) terephthalamide (BHETA) and the glycolysis process to produce bis (2-hydroxy ethylene) terephthalate (BHET) were examined. The study's findings show that higher temperatures (180 °C) are beneficial for PES textile waste conversion and BHETA yield, which can reach nearly 95% and 94%, respectively. Finally, FT-IR, 1H NMR, and mass spectroscopy (MS) were used to characterise the depolymerized products. The study showed that 2 mol% Ag-doped ZnO showed better catalytic activity.

In this work, Bi2WO6/TiO2 nanorod heterojunction was prepared by sonochemical assisted impregnation method. After loading 2 wt% Bi2WO6 on TiO2 nanorods, the photocatalytic hydrogen production rate of 2026 µmol/h/g was achieved. Compared to commercial P25 and TiO2 nanorods, ∼13 and ∼3 folds enhanced activity was observed. The excellent photocatalytic performance of Bi2WO6/TiO2 nanorod photocatalyst was mainly attributed to i) reduction of bandgap due to heterojunction formation, ii) quick transport of photogenerated charge carriers, and iii) efficient charge carrier separation supported by UV-DRS, photocurrent measurement, Impedance study, and photoluminescence spectra analysis. The Z-scheme band alignment for Bi2WO6/TiO2 nanorod heterojunction was proposed based on the Mott-Schottky measurement. This result demonstrated the effective utilization of Z-scheme heterojunction of Bi2WO6/TiO2 for photocatalytic reduction application.

The light soaking process is a well-known technique to mitigate defects on the surface and the energy band mismatch of the TiO2-based cathode interfacial layer (CIL) in organic solar cells (OSCs). ...

Nanosized ZnO-based materials for catalytic and sensing applications are highly proficient over bulk catalytic analogous due to higher surface and tunable physicochemical properties. The functionality, porosity, shape, size and surface area of these nanomaterials are crucial factors for influencing specificity and efficiency of its applications. In this review, we contemplated the effect of metal doping on ZnO nanoparticles for various applications such as solar cells, photocatalysis, medicines, light-emitting diodes, laser diodes, chemical and biosensors. The potential applications of metal-doped ZnO have gained significant attention owing to direct influence by the dopants on electronic and physiochemical properties. Especially, the natural bandgap (3.37 eV) and n-type conducting behaviour of ZnO can be tuned by doping of metals/metal oxides and non-metals by replacing Zn2+ and O2- in ZnO lattices respectively. Further, the bandgap modified ZnO could be used as a multi-functional material by growing it in various nanostructures such as bulk, thin layer and wires.

Photocatalysis is one of the fascinating fields for the wastewater treatment. In this regard, the present study deals with an effective visible light active BiYO3/g-C3N4 heterojunction nanocomposite photocatalyst with various ratio of BiYO3 and g-C3N4 (1:3, 1:1 and 3:1), synthesised by wet chemical approach. The as-synthesised nanocomposite photocatalysts were investigated via different physicochemical approaches like Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electrons microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and photoelectrochemical studies to characterise the crystal structure, morphology, optical absorption characteristics and photoelectrochemical properties. The photocatalytic degradation ability of the prepared photocatalytic samples were also analysed through the degradation of RhB in the presence of visible light irradiation. Of all the synthesised photocatalysts, the optimised CB-1 composite showed a significant photocatalytic efficiency (88.7%), with excellent stability and recyclability after three cycles. O2.− and •OH radicals were found to act a major role in the RhB degradation using optimised CB-1 composite and it possessed ~ 1 times greater photocurrent intensity than the pristine g-C3N4 and BiYO3. In the present work, a direct Z-scheme heterojunction BiYO3/g-C3N4 with a considerably improved photocatalytic performance is reported.

A novel FeMoO4/g-C3N4-2D/2D Z-scheme heterojunction photocatalyst was prepared via wet chemical method. The observed structural morphology of FeMoO4/g-C3N4 reveals the 2D-iron molybdate (FeMoO4) nanoplates compiled with the 2D-graphitic carbon nitride (g-C3N4) nanosheets like structure. The photocatalytic activity of the g-C3N4, FeMoO4, and FeMoO4/g-C3N4 composites were studied via the degradation of Rhodamine B (RhB) as targeted textile dye under visible light irradiation (VLI). The optimal FeMoO4/g-C3N4 (1:3 ratio of g-C3N4 and FeMoO4) composite show an enhanced degradation performance with rate constant value of 0.02226 min-1 and good stability even after three cycles. Thus, the h+ and O2•－are the key radicals in the degradation of RhB under VLI. It is proposed that the FeMoO4/g-C3N4 Z-scheme heterojunction effectively enhances the transfer and separation ability of e-/h + pairs, by the way increasing the photocatalytic efficiency towards the RhB degradation. Thus, the newly constructed Z-scheme FeMoO4/g-C3N4 heterojunction photocatalyst is a promising material for the remediation of wastewater relevant to elimination of toxic effect in marine environment.

A hierarchical structure composed of Pt@Co3O4/TiO2 (CTP) ternary nanocomposite was synthesized and demonstrated for its enhanced and durable production of hydrogen from glycerol under simulated solar light irradiation. The rate of hydrogen production over the optimized composition was found to be 19.2 mmol h−1 g−1cat. The obtained XRD and XPS results revealed the facile formation of the composite. The heterojunction formed in the ternary system remarkably enhanced the visible light absorption properties and charge separation in CTP as evidenced from their UV–visible absorption and PL spectra, respectively. The optimized union of the materials with specific properties and their intimate physical contacts might be the origin for the manifested, improved and durable photocatalytic efficiency towards hydrogen production.

This paper proposes a real-time simulation model to simplify the research and outcome of a portable thermoelectric generator (TEG) system in real conditions. Consequently, the model is divided into three parts: conventional, segmented, and hybrid TEG systems. The conventional TEG system consisted of Bi2Te3 as the p-type and the n-type materials, whereas the segmented and the hybrid TEG systems consisted of a different combination of materials, including PbTe and Sb2Te3. The optimization of the TEG system length was carried out to achieve the highest power output, which was found to be 2 mm. In addition, thermomechanical stress distribution analysis of the module was conducted to determine the maximum load the TEG system could withstand before undergoing fracture, depending upon the yield strength of the material. The stress was analyzed in all three TEG systems, and the results were evaluated. Results were observed from the optimized length at 2 mm. The conventional, segmented, and hybrid TEG systems showed maximum power output of 147.122 mW, 171.934 mW, and 550 mW, respectively, with a temperature difference at 50 K.

Photocatalytic H2 evolution has been proven to be one of the promising methods for tackling global energy and environmental issues. In this work, rGO supported TiO2/In0.5WO3 S-scheme heterojunction photocatalyst was prepared by using the hydrothermal and wet impregnation methods. The crystallinity and morphology of synthesized photocatalysts were ascertained by XRD, FESEM, and TEM. The results showed high crystallinity and distribution of TiO2/In0.5WO3 on rGO sheets. The photocatalytic activity of synthesized photocatalyst was evaluated towards photocatalytic H2 production. It was noted that compared to bare TiO2 (24.15 ± 1.8 μmol/h/g), TiO2/In0.5WO3 (132.6 ± 5.1 μmol/h/g) and rGO supported TiO2/In0.5WO3 (309.98 ± 11.4 μmol/h/g) photocatalysts showed ~ 5 and ~ 12 folds enhanced photocatalytic H2 production activity. Further, 5.2, 11.3 and 15.6% AQE was achieved at 365 nm for TiO2, TiO2/In0.5WO3 and rGO supported TiO2/In0.5WO3. This was mainly attributed to improved light absorption by TiO2/In0.5WO3 and rapid charge carrier separation characteristics of rGO as revealed by UV–vis DRS, Photoluminescence spectroscopy and Photocurrent studies. Based on photoelectrochemical results, a direct S-scheme heterojunction charge transfer mechanism was proposed to explain the significantly enhanced photocatalytic performance of rGO supported TiO2/In0.5WO3 photocatalyst. This work stipulates new comprehensions into the construction of S-scheme heterostructure through rGO as a solid-state mediator.

The development of noble metal-anchored semiconductors for photocatalytic processes is now garnering interest for potential application to toxic pollutants as well as antibiotic degradation. Herein, we report novel Ag@p-g-C3N4–Bi2MoO6 nanocomposites synthesized by facile hydrothermal and calcination methods with a size of about 50 nm, exhibiting superior photocatalytic activity for charge separation. The resulting nanocomposites were evaluated by various physiochemical techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. The charge transfer photogenerated carriers were confirmed by photoluminescence spectra and electrochemical impedance spectroscopy. The anchoring of Ag nanoparticles over p-g-C3N4/Bi2MoO6 decreased the band gap energy from 2.67 to 2.48 eV, to exhibit an abnormal increase in absorption of light towards the visible light region. The degradation performance of the nanocomposites in terms of antibiotic ciprofloxacin and rhodamine B degradation efficiency was measured 85 and 99.7% respectively. The superoxide radical anion ˙O2− played a significant role throughout the entire degradation process. Focusing on the probable mechanism based on the desirable results, the present work follows the heterostructure mechanism. Moreover, this work features the feasible applications of Ag@p-g-C3N4–Bi2MoO6 as a modified photocatalyst in the treatment of both domestic and industrial waste water.

Construction of the Z-scheme heterojunction photocatalyst achieved highly improved photocatalytic ability by its high redox ability of the photoinduced e−-h+ pairs. In the study, Z-scheme g-C3N4/BiYWO6 heterojunction photocatalyst is prepared by the single step hydrothermal method. Further, its photocatalytic ability was assessed by degrading methylene blue under visible light exposure. Particularly, the optimized 30 wt. % of g-C3N4 in the g-C3N4/BiYWO6 composite exposes almost complete degradation after 90 min, that is ~ 3.0 times greater than the bare BiYWO6 and g-C3N4 with the rate constant value 0.032 min− 1. Experimentally, the radical trapping studies indicates O2.− and .OH radicals are playing vital role in the photocatalytic degradation process. Also, Z-scheme g-C3N4/BiYWO6 heterojunction photocatalyst exhibits excellent photoelectrochemical property and it is stable after three cycles, which indicates its good reusability nature. These enhancements are due to the newly formed heterostructure that facilitates the migration and separation efficiency of the photoproduced e−-h+ pairs. Hence, the synthesized Z-scheme g-C3N4/BiYWO6 heterostructure could be an excellent material for wastewater remediation works.

Construction of the Z-scheme heterojunction photocatalyst achieved highly improved photocatalytic ability by its high redox ability of the photoinduced e

Photocatalysis is one of the promising method to degrade harmful organic pollutants under visible light exposure. In this work, a novel Ni

Visible-light-driven hydrogen production is a promising pathway to realize efficient solar energy utilization. Here, Nd3+ incorporated ZnIn2S4 (Nd-ZIS) was synthesized via facile one step hydrothermal method. Raman spectroscopy and X-ray Photoelectron Spectroscopy (XPS) confirm the successful incorporation of Nd3+ in ZnIn2S4. Optical studies reveal the reduction of effective bandgap from 2.7 eV to 2.54 eV upon incorporation of Nd3+ with improved charge carrier life time of 3.12 ns. Electronic properties of ZIS and Nd-ZIS were investigated from first principle calculations. An attempt to improve photocatalytic activity of ZIS by modification with Nd3+ ions resulted in degradation of organic pollutant up to 98% under natural sunlight and decrease in life time of trap states up to a nominal value of 200 ms (as evident from photoelectrochemical measurements). The mechanism behind enhancement of photocatalytic activity of ZIS post Nd3+ integration has been proposed. Nd-ZIS was also utilized for water splitting activity exhibiting a considerable H2 generation ∼3415 μmol g−1. To the best of our knowledge, activity of Nd3+ incorporated ZIS has been explored for the first time in present work. It is believed that an in-depth understanding of photoactivity of ZIS would be significantly important for designing materials with desired photocatalytic performance in future.

In this work, the efficiency of dye-sensitized solar cells (DSSC) was improved by capping TiO2 with simple aromatic amines as a complexing agent. The aromatic amines, aniline and o-phenylenediamine capped TiO2 composites were synthesized via hydrothermal route and used as scattering layer in dye-sensitized solar cell (DSSC). Markedly, the maximum photo-conversion efficiency of 9.84% was achieved with o-phenylenediamine capped-TiO2 composite as o-phenylenediamine capped-TiO2 showed higher reflectivity than the pristine TiO2, which is highly beneficial for reflecting the photons back to photoanode. In addition, the average life time of carriers in o-phenylenediamine capped-TiO2 was found to be 9.8 ms, which was 2 times higher than the pristine TiO2 (4.29 ms).