Search

Two-dimensional mixed metal oxides have attracted attention because of their unique characteristics and diverse crystal structure. In this work, we have synthesized zinc vanadium oxide and its nanocomposite with graphitic-carbon nitride via wet-chemical and hydrothermal methods. XRD analysis unsheathe the ZnV 2 O 6 /g-C 3 N 4 for wet-chemically synthesized composite while Zn 2 V 2 O 7 /g-C 3 N 4 for hydrothermally prepared composite. The sample synthesized using the wet-chemical process, has an agglomerated structure in the FESEM micrographs while hydrothermally synthesized sample reveal porous nanosheets of the composite material. Zn 2 V 2 O 7 /g-C 3 N 4 is further characterized with XPS and HRTEM. UV–visible spectroscopy was used to describe the material's optical characteristics and the Tauc relation was used to compute the associated optical bandgap. The as-synthesized composites were assessed as an electrochemical sensing material for ascorbic acid sensing in a neutral pH analyte (PBS). Furthermore, Zn 2 V 2 O 7 /g-C 3 N 4 shows exceptional photocatalytic CO 2 reduction and yielded CH 4 as a result. As-prepared nanocomposites can be used in commercial applications for electrochemical diagnostics and photocatalytic applications. • Synthesized Zinc Vanadium Oxide and its g-C3N4 nanocomposite via wet-chemical and hydrothermal methods. • SEM and XRD analysis revealed structural differences between methods. • UV–visible spectroscopy used for optical property analysis and bandgap calculation. • Material demonstrated efficacy as a neutral pH ascorbic acid sensor. • Exceptional photocatalytic CO2 reduction, yielding methane. [ABSTRACT FROM AUTHOR]

This study investigates into the synthesis, characterization, and multifaceted analysis of a composite material comprised of copper vanadium oxide (CVO) and graphitic Carbon Nitride g-C 3 N 4 (GCN). The fabrication of the composite was achieved through wet-chemical method followed by annealing at 600 °C for 3 h, ensuring controlled composition and structure. The characterization process encompassed X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–visible spectroscopy, unveiling the composite's crystalline structure, novel nano-rod morphology with decorated flakes, and UV–visible light activation capability. The obtained band gap of approximately 2.7 eV signified the composite's optical properties. Electrochemical analysis, including cyclic voltammetry (CV), highlighted the composite's robust biosensing attributes, particularly in response to ascorbic acid. The conducting and metallic characteristics of the composite enhanced its reactivity, promising applications in biosensors and energy storage devices. This comprehensive investigation elucidates the multifaceted potential of the CVO/GCN nano-composite across diverse optoelectronic realms. [ABSTRACT FROM AUTHOR]

We demonstrated a nonenzymatic electrochemical sensor based upon vanadium-doped nickel oxide composite with graphitic carbon nitride. The g-C 3 N 4 was prepared by annealing Urea at 550 °C for 3 h in a muffle furnace. The nanocomposite was synthesized using a microwave-assisted method, followed by thermal annealing at different temperatures. The successful formation of V–NiO/g-C 3 N 4 was confirmed by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy. SEM images show the layered sheets with porous structure, which depends on annealing temperature; as we increase the temperature, the porosity increases. Afterwards, the electrochemical sensing properties were verified by CV, LSV, DPV, and amperometric studies in 0.2 M KOH in the presence of Ascorbic acid and Dopamine. The experimental results show that our prepared sample has excellent electrochemical biosensing abilities towards AA and DA with LOD 1.16 μM and 0.16 μM, respectively. It also offers good selectivity, exceptional reproducibility, and long-term stability owing to the combined effect of NiO and g-C 3 N 4. Finally, the electrochemical sensing of H 2 O 2 was detected in the same environment by conducting CV and amperometric studies. Our modified electrode has proven its noble ability to sense H 2 O 2 with excellent repeatability, stability and low LOD 0.2 μM with a wide linear working range (0.5 mM–4 mM). It has the potential to be used for multi-molecule selection biosensing with excellent selectivity and sensitivity. [Display omitted] [ABSTRACT FROM AUTHOR]

Summary: Recently, an emerging new class of cubic π‐polymorphs are being pursued as cost‐effective and relatively less toxic materials for thermoelectric, photovoltaic, and optoelectronic applications. Using density functional formalism and semiclassical Boltzmann transport theory, we have systematically studied the thermoelectric performance of π‐polymorphs. Hybrid functional (HSE03) is employed to realize accurate energy bandgaps, which helps to predict more accurate thermoelectric properties. The thermodynamic stability is observed by binding energies and phonon dispersions. It is observed that the Seebeck coefficients (S) are decreasing and electrical conductivities (σ) are increasing with carrier concentration. However, thermal conductivities are showing decreasing trends which lead to ultimately increased ZT. π‐GeSe shows a high power factor ~16.50 mW/mK2 among all π‐polymorphs. The figure of merit, ZT value, of π‐SnS, π‐SnSe, π‐GeS, and π‐GeSe are found to be 0.83, 1.20, 1.28, and 1.63 with optimal carrier concentration at 800 K. The present work highlights the potential of newly discovered cubic π‐polymorphs of chalcogenides for highly efficient thermoelectric materials. [ABSTRACT FROM AUTHOR]

Vanadium Pentoxide is considered as an intriguing material for several advanced technological applications such as supercapacitors, Lithium-ion batteries, photo-catalysis and optical waveguide. In this work, we have presented a facile and non-toxic method for the synthesis of Vanadium Pentoxide nanobelts. Considering the aforesaid motivations, we tuned the size of Vanadium Pentoxide nanobelts by simply varying the synthesis temperature. The XRD results confirm that the obtained phase is Vanadium Pentoxide with no impurities found within the experimental limitations. The analysis by Scanning Electron Microscopy (SEM) depicts that the diameter of nanobelts decreased from 52.7nm to 44.7nm with the increase in synthesis temperature within range 180oC-220 °C respectively. The UV–Vis-Spectrum shows that bandgap of nanobelts increased in the range 2.25eV-3eV with the increase in synthesis temperature within range 180oC-220 °C. For field emission measurements, the variation in field enhancement factor and turn-on voltage is also observed. These results indicate that by just varying a simple parameter one can tune the band gap and electronic properties of Vanadium Pentoxide nanobelts. These studies show that Vanadium Pentoxide nanobelts can be promising candidate for optoelectronic device. [ABSTRACT FROM AUTHOR]

• First ever optical, mechanical and anisotropic properties of cubic GeX (X = S, Se) are studied. • 2D & 3D surface visualization suggest that both chalcogenides are elastically anisotropic. • Debye temperature (θ D) of π-GeS and π-GeSe are 262.28 K and 264.46 K, respectively. • Germanium chalcogenides are promising candidate for optoelectronic, thermoelectric devices. Newly discovered cubic phase of Germanium monochalcogenide (π-GeS and π-GeSe) with a moderate bandgap, less toxicity, and novel electronic properties have earned significant attention of researchers due to appropriate nature for the energy-related applications such as photovoltaic, optoelectronic and thermoelectric devices. The structural, electronic (band structure and DOS), optical and elastic properties of π-GeS and π-GeSe have been studied by ultrasoft pseudopotential technique. The band structure calculations confirm that both π-GeS and π-GeSe are indirect in nature with bandgap energies 1.38 and 1.04 eV respectively. The first-time calculated elastic constants of π-GeS and π-GeSe satisfy their mechanical stability criteria (Born stability). The elastic moduli (bulk, Young's, shear), Lame's parameters, Poisson's ratio, Debye temperature, and average sound velocity are determined by Voigt-Reuss-Hill approximation. The shear and Young's elastic properties reveal that both π-GeS and π-GeSe are anisotropic, which is also confirmed from 2D and 3D surface visualization. The calculated Debye temperature (θ D) of π-GeS and π-GeSe are 262.28 K and 264.46 K at 300 K, respectively. Additionally, the longitudinal and transversal waves sound velocities are calculated for the first time in [1 1 1], [1 1 0] and [1 0 0] directions. The present results reveal that π-GeS and π-GeSe could be appropriate candidates for exploitation in energy storage, optoelectronic and thermoelectric devices. Particularly GeS, which has higher absorption peaks and optimum bandgap (1.38 eV) for practical photovoltaic and photo-sensing applications. The present work provides the pathways for theoretical and experimental studies on electronic devices based upon cubic chalcogenides. [ABSTRACT FROM AUTHOR]

Abstract Recently, Tin Monoxide (SnO) has attained a considerable interest due to its striking electronic, optical, thermoelectric and gas sensing properties in various advanced technological applications. In this study, we focus on the first principles calculations to examine the structural, electronic and optical properties of the pristine, 1S, 2S, and 3S doped SnO. The plane-wave ultra-soft pseudopotential method is used under the GGA-PBE exchange-correlation energy with supercell approach. Bandgap reduces with the increase in the concentration of doping from 0.460 eV to 0.330 eV, 0.064 eV for 1S, 2S respectively and shows metallic behavior for 3S doped SnO. Formation and cohesive energies decrease in order of Sn 15 S 1 O 16 < Sn 14 S 2 O 16 < Sn 13 S 3 O 16, which shows that the most suitable and favorable configuration is of Sn 15 S 1 O 16. The static dielectric constant ε 1 (0) and refractive index n (0) are 7.71, 7.82, 8.48, 9.42 eV and 2.76, 2.80, 2.91, 3.07 respectively, which are showing increasing trends. The absorption spectrum and optical conductivity curves of S doping show a significant blueshift towards ultraviolet spectrum. The optical properties and bandgap narrowing effect suggest that the sulfur-doped SnO can be a promising new semiconductor in the field of optoelectronics. [ABSTRACT FROM AUTHOR]

Recently discovered novel π-SnS (cubic phase) has gained much attention due to suitable nature for several optoelectronic devices and thermoelectric applications. Local density approximation (LDA) and generalized gradient approximation (GGA) with ultra-soft pseudo-potential (UPP) technique within density functional theory (DFT) are used to study the structural, electronic, optical, and elastic properties of π-SnS. The structural properties show good consistency with previous results. The band structure study shows that its nature is indirect with bandgap 1.073/1.37 eV (LDA/GGA). The calculated elastic constants satisfy the Born stability criteria which are determined for the first time as per our knowledge. On the basis of Voigt-Reuss-Hill approximation, bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, Lame’s coefficients, average sound velocity and Debye temperature are determined. In LDA/GGA the value of Bulk modulus is estimated 55.32/20.98 GPa, which is in good agreement to that calculated with Birch-Murnaghan equation of state (EOS). The 2D and 3D surface visualization of bulk, shear and Young’s moduli suggest that π-SnS is elastically anisotropic. In LDA/GGA the value of Debye temperature (θ D ) is estimated as 361.01/299.39 K. The thermal conductivity of π-SnS could be high due to high Debye temperature (θ D ) relative to α-SnS (θ D  ∼ 270 K). Additionally, for the first time transversal and longitudinal wave velocities in [1 0 0], [1 1 0] and [1 1 1] directions are calculated. In the view of present studies π-SnS could be suitable candidate for exploitation in optoelectronic, thermoelectric and energy storage devices. [ABSTRACT FROM AUTHOR]

The novel cubic phase π-SnSe has recently garnered interest in solar cells, optoelectronic devices and thermoelectric applications. In this work we present the structural, electronic, optical, and elastic properties of π-SnSe using ultrasoft pseudo-potential technique based on density functional theory with local density approximations (LDA) and generalized gradient approximations(GGA). The analysis of band structure provides an indirect bandgap of magnitude 0.799/1.011 eV (LDA/GGA). For the first time, we have calculated elastic constants values which also satisfy the Born stability criteria. The bulk, shear, Young's moduli, Poisson's ratio, Lame's coefficients, average sound velocity and Debye temperature are estimated in the framework of the Voigt-Reuss-Hill approximation. The calculated Bulk modulus is recorded as 61.18/16.33 GPa (LDA/GGA), which matches well with the values extracted from the Birch-Murnaghan equation of state. π-SnSe can be characterized as an elastically anisotropic material by the analysis and visualization of the directional dependence of bulk, shear and Young's moduli. The calculated Debye temperature (θ D ) from LDA/GGA is found as 314.86/214.88 K. The thermal conductivity of π-SnSe could be high due to high Debye temperature as compared to orthorhombic phase of SnSe (θ D ∼210 K). Moreover, the longitudinal and shear wave velocities in three different directions [100], [110] and [111] are also predicted for the first time. These studies provide an insight into various aspects and properties of novel phase cubic SnSe for better understanding and exploitation/design in optoelectronic and energy storage devices. [ABSTRACT FROM AUTHOR]

The novel cubic structured SnSe (π-SnSe), with narrow band-gap and substantial phonon restraining effect, is considered a perspective energy storage material for futuristic applications. In this study, we explore the thermoelectric properties of π-SnSe in the framework of density functional theory and is therefore believed to be the first report of its kind. As a prerequisite for the calculations of thermoelectric properties, the electronic structure of π-SnSe was determined at the level of modified Becke-Johnson potential. The calculated bandgap of magnitude 0.97 eV is found to be in good agreement with recently reported experimental results of energy band-gap. Our calculations for electrical conductivity (σ/τ) show that the highest values occur at modest doping level magnitude to 3.6 × 10 19 / Ωms for p -type doping and 1.54 × 10 20 / Ωms for n -type doping and was found to be decreasing linearly with increasing temperature. Similarly, it is found that π-SnSe exhibit high Seebeck coefficient at low temperature, observing a drastic degradation in the span of 2292 μK/V to 444.3 μK/V with increasing temperature ranging from 200 to 900 K, respectively. In consequence, a notable reduction in the values of thermoelectric power factor (PF) and figure of merit (ZT) has also been observed with increase in temperature. The maximum value of PF was documented to be 8.77 × 10 10 W/mK 2 s at 200 K. An exceptionally high and record ZT value of ∼1 was obtained at 200 K which is superior to orthorhombic structure SnSe (polycrystalline and bulk). Thus our study point to cubic phase SnSe as an avenue for the next generation thermoelectric materials for a wide range of operational temperature devices. [ABSTRACT FROM AUTHOR]

The narrow bandgap Tin Selenide (SnSe) is a promising material for optoelectronic, photovoltaic and thermoelectric applications. A new phase cubic π-SnSe is investigated under pressure for the first time. The studies were carried out by applying uniaxial hydrostatic pressure on π-SnSe structure from 0 GPa to 40 GPa. The results indicate that the structural parameters such as lattice parameters and cell volume show inverse relation to the pressure and shows smooth decreasing behaviour from 0 to 40 GPa. The bandgap of π-SnSe shows a significant variation at different external hydrostatic pressure (GPa). At 0 GPa its bandgap nature is direct and when pressure started to increase from 5 to 30 GPa it shows an indirect nature, and at further increase of pressure it started to exhibit the metallic behaviour (35–40 GPa). From the detailed analysis of the optical properties, it is concluded that external pressure might be the key reason to enhance the near/mid infrared light activity. The value of static dielectric constant and refractive index changes from 10.10 to 76.20 and 3.18 to 8.74 respectively as pressure increases from 0 to 40 GPa. Also, absorption energy increases as new peaks started to emerge with the increase in pressure. Moreover conduction shows substantial variation from 4.63 to 10.80 (1/fs) with pressure. The optical property enhancement is mostly due to the pressure modified electronic structures of π-SnSe (cubic phase). The tuning/manipulation of the structural and optical properties of π-SnSe suggest that this new cubic phase has a wide range of applications for pressure based optoelectronic systems. [ABSTRACT FROM AUTHOR]

In this study we have used continuous microwave flow synthesis (CMFS) technique to synthesize nanosized titania (TiO 2 ). The effect of microwave power (MwP) on the physicochemical properties of TiO 2 has been evaluated. Particle morphology and degree of crystallinity were studied using TEM and XRD respectively. The specific surface area was quantified by using BET method and catalytic degradation of methylene blue (MB) was also measured. The UV–vis studies identified a red-shift in the energy bandgap ( E g = 2.95 eV) of TiO 2 and the photoluminescence (PL) study revealed a significant reduction in the surface oxygen defects under the influence of increased MwP. This study has demonstrated that, due to the visible region E g , TiO 2 nanoparticles can be used effectively as a photocatalyst and as photovoltaic solar cell material. [ABSTRACT FROM AUTHOR]

The hierarchical nanostructures (HNs) have engrossed immense attention due to their superior performance in catalysis, electronic and energy storage/conversion devices. The multicomponent transition metal oxides (TMOs) have been pointed out as more promising materials for advanced technological applications as compared to their counter binary oxides. Due to the advantages of hierarchical nanostructures and TMOs we have synthesized novel Zn 2 V 2 O 7 hierarchical nanostructures using template free route. The photoluminescence of the sample exhibited an emission at 553.65 nm which can be useful for light emission devices. The hydrogen storage of Zn 2 V 2 O 7 HNs were measured at 473 K and 573 K with an absorption of 1.21 wt.% and 1.81 wt.%., respectively. These studies point out a new class of nanomaterials for possible applications for energy storage and green emission optoelectronic devices. [ABSTRACT FROM AUTHOR]

Tin dioxide (SnO 2 ) ultralong nanobelts were fabricated on silicon substrate by metal catalyzed Chemical Vapor Deposition (CVD) approach. An optical bandgap of 3.66 eV was calculated by optical absorbance data. Three Raman active modes peaks were observed at 474.4, 633 and 774.4 cm −1 . Room temperature photoluminescence (PL) exhibited an orange emission at 600 nm. A vapor–liquid–solid (VLS) process based growth mechanism for the formation of SnO 2 nanobelts was proposed and discussed briefly. Electrical transport characteristics of nanobelts were studied in dark and under ultraviolet (UV) laser. The fabricated device exhibited high photo-response properties under UV light, indicating their potential application as photo-switches and UV detectors. [ABSTRACT FROM AUTHOR]

Abstract: We present first study on ZnV2O4 glomerulus nano/microspheres synthesize by template free route to expose its hydrogen storage potential. Besides this the evolution of nano/microspheres has been investigated in detail. To reveal possible growth mechanism of these spheres, time-dependent experiments are performed. Reitveld analysis is taken into account for calculation of lattice parameters, crystallite size and strain. From our results, a correlation between lattice parameters and crystallite size is observed. The strain decreases with the increase in reaction time. Hydrogen storage measurement reveals potential of ZnV2O4 nanospheres as a prospective material for energy storage applications. These studies can open new avenue of research for hydrogen storage in spinel oxide materials. [Copyright &y& Elsevier]

For the first time, high quality SnSe nanowires were synthesized via chemical vapour deposition (CVD). The synthesized SnSe nanowires are single crystalline. The length of the nanowires is in tens of microns with an average diameter of about 30-40 nm. Further, the optical and electrical properties reveal the potential of SnSe nanowires for photovoltaic and optical devices. These studies will enable significant advancements of the next generation photodetection and solar cell applications. [ABSTRACT FROM AUTHOR]

We report the synthesis of ZnV2O4 spinel oxide novel nanosheets via a template free route to explore its potential hydrogen storage properties for the first time. 2D layered nanostructures are excellent candidates for storage applications. This attracted our interest to synthesize novel spinel oxide nanosheets (NSNs) of ZnV2O4. The maximum value for hydrogen absorption in ZnV2O4 nanosheets at 473 K is 1.36 wt.% and 1.74 wt.% at 573 K, respectively. Our hydrogen storage measurements along ZnV2O4 reveal its superiority over previous reports on hydrogen absorption values concerning oxides, nitrides and chalcogenides. To understand the rate-limiting mechanism, various kinetics models are applied. The calculations show that kinetics is governed by 3D growth with constant interface velocity. The measurements point to ZnV2O4 spinel oxide as a promising hydrogen storage material. PL measurements demonstrate the potential for violet/blue optoelectronic devices. [ABSTRACT FROM AUTHOR]

Fabrication of SnO2nanobelts has been carried out by employing vapour liquid solid (VLS) and vapour solid (VS) mechanism. Nanobelts obtained by VLS mechanism were fabricated at relatively low temperature using Fe powders as a catalyst by means of chemical vapour deposition (CVD) technique. Direct thermal evaporation of SnO2nanobelts was carried out at 1350°C in the atmosphere of Argon gas via VS mechanism. In both cases, ramp rate was adjusted to 10°C/min. The structural, compositional and morphological characterisations of synthesised SnO2nanobelts were conducted by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X‑ray spectroscopy (EDS). Magnetic behaviour of the nanobelts was studied by vibrating sample magnetometer (VSM). Cathodoluminescence (CL) spectra were studied using Renishaw Raman spectroscopy system. The growth of nanobelts is found to be homogeneous and dense. The nanobelts formed by VLS mechanism show ferromagnetic behaviour along with some other exciting results whereas the nanobelts formed by VS mechanism show a diamagnetic behaviour. The observed room temperature ferromagnetism in SnO2nanobelts is superior to other oxides. [ABSTRACT FROM PUBLISHER]

Abstract: Here we report the synthesis of highly pure single crystalline tin selenide (SnSe) nanospheres by pretreatment of precursors with aqueous ammonia. In this work we have demonstrated that aqueous ammonia not only controls the preferred growth orientation but also controls the morphology of SnSe. Chemical vapor deposition technique was used for the growth of SnSe nanostructures. The optical properties were studied using UV–vis–NIR spectroscopy and Photoluminescence (PL) spectrum. [Copyright &y& Elsevier]

Abstract: Here we report on the synthesis of novel SnO2 nanofibers bundle (NFB) by using ball milled Fe powders via chemical vapor deposition (CVD). The reaction was carried out in a horizontal tube furnace (HTF) at 1100°C under Ar flow. The as prepared product was characterized by X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, high resolution transmission electron microscopy and selected area electron diffraction (SAED). The microscopy analysis reveals the existence of tubular structure that might be formed by the accumulation of nanofibers. The Raman spectrum reveals that the product is rutile SnO2 with additional peaks ascribed to defects or oxygen vacancies. Room temperature Photoluminescence (PL) spectrum exhibits three emission bands at 369, 450 and 466.6nm. Using optical absorbance data, a direct optical bandgap of 3.68eV was calculated. [Copyright &y& Elsevier]

This study investigates the photocatalytic degradation of nitrogen oxides over graphitic carbon nitride (g-C 3 N 4) based photocatalysts. The synthesis procedure of g-C 3 N 4 consists of two-step: in the first step, the synthesis of g-C 3 N 4 is carried out through a microwave heating method, whereas in the second step the as-synthesized product is annealed. The characterization was carried out by XRD (X-ray Diffraction), FESEM (Field Emission Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), BET (Brunauer-Emmet-Teller), and XPS (X-ray Photoelectron Spectroscopy). Photocatalytic activities for the degradation of NO x (Nitrogen Oxides) are compared with commercial TiO 2 and g-C 3 N 4 , to investigate the structural and physio-chemical features of prepared samples and their correlation with the catalytic activity. The results show that g-C 3 N 4 nanosheets have better activity and stability as compared to TiO 2. The deposition effect of 1 wt% Pt to the g-C 3 N 4 nanosheets is also observed which puts a negative effect on the degradation results. [Display omitted] • The material was synthesized by heating up the suspension at 110°C for 30 mins in microwave oven MAS-II plus at 300W. • It is observed through surface analysis the structure of g-C 3 N 4 nanosheets is porous with an estimated pore size of 20 nm. • In XPS analysis the peak at 399.6 eV shows most of the nitrogen in g-C 3 N 4 contributes to the C-N-C groups. • g-C 3 N 4 nanosheets shows better performance as compared to TiO 2 with 9.5% NO conversion and 0.33% photonic efficiency [ξ]. [ABSTRACT FROM AUTHOR]

We report here large scale synthesis of ZnV 2 O 6 nanostructures via facile, template free and cost effective method. For the first time hydrogen storage and supercapacitor properties of ZnV 2 O 6 nanostructures were measured, which were found to be 1.32wt% and 380 F/g, respectively. Electrochemical supercapacitor device was fabricated using three electrode configuration and electrochemical measurements revealed ZnV 2 O 6 nanostructures as a promising candidate for energy storage/conversion material. PL measurements on ZnV 2 O 6 showed a broad emission centered at 392 nm. Our investigation has shown that ZnV 2 O 6 nanostructures has the potential to be used as an energy storage material and in blue optoelectronic devices. [ABSTRACT FROM AUTHOR]

The transition metal dichalcogenides (TMDs) are considered as promising candidates for their striking performance in optoelectronic properties. We have designed the novel heterostructures XSe 2 /SnS using XSe 2 (X = Pt, Zr, Hf) TMDs. The stabilities of structural, mechanical, dynamical, and thermal are calculated by formation energies, elastic constants, phonon dispersions and AIMD simulations respectively. The hybrid functional (HSE06) is used to calculate the electronic band structures and optical absorption. The DFT scheme (BGC based) indicates that XSe 2 /SnS vdWHs are viable photocatalyst for overall water splitting over a broad spectrum of light. The absorption spectra exhibit that these photocatalysts have absorption started from visible to the UV region of light in the order of 105. XSe 2 /SnS heterostructures display high carrier mobilities of order 104. The Gibbs free energies exhibit that PtSe 2 /SnS heterostructure has spontaneous, whereas other heterostructures need some external energies for overall water splitting. Finally, the corrected STH efficiency of PtSe 2 /SnS, ZrSe 2 /SnS and HfSe 2 /SnS vdW heterostructures are 12.54%, 28.15%, 21.03% respectively. This study depicts that XSe 2 /SnS (X = Pt, Zr, Hf) heterostructures are feasible candidates for overall water splitting over a broad range of light spectrum. [Display omitted] • XSe 2 /SnS (X = Pt, Zr, Hf) vdWHs possess bandgaps in range of 1.3–2.2 eV. • Above mentioned vdWHs show absorption in visible and UV region in range 105 cm−1. • XSe 2 /SnS (X = Pt, Zr, Hf) vdWHs display excellent carrier mobilities (104 cm2 v−1 s−1). • Gibbs free energies are computed to further explore photocatalytic activities. [ABSTRACT FROM AUTHOR]

The rising energy demand via renewable sources and existence of organic pollutants in water has attracted the world-wide attention to attain sustainable ecosystems. The development of a multi-functional catalyst with significant economic and environmental implications remains a challenge. Herein, we synthesized SnS 2 /g-C 3 N 4 hierarchical nanoflower using solvothermal method, verified by XRD and FTIR investigations. The surface morphology was analyzed using FESEM, TEM and HRTEM while optical absorption via UV–Vis spectroscopy. SnS 2 /g-C 3 N 4 displayed outstanding electrocatalytic activity for HER and OER with smaller tafel slope and higher values of current density. The results are in accordance with C dl and ECSA values, ensuing more active sites and surface area for a catalytic reaction to take place. As-prepared SnS 2 /g-C 3 N 4 also exhibited 90 % photocatalytic MB deterioration in 90 min upon solar irradiation, following first order kinetics. Type-II mechanism for charge transfer alongwith reactive specie trapping experiment and cyclic stability is also presented. The findings suggests that SnS 2 /g-C 3 N 4 emerged as proficient catalyst for electrocatalytic and photocatalytic applications. [Display omitted] [ABSTRACT FROM AUTHOR]

10.3390/catal10101196 5 Dai Y., Lu C., Liang L., Feng N., Wang J. Visible Light Electromagnetic Interaction of PM567 Chiral Dye for Asymmetric Photocatalysis, a First-Principles Investigation. Chen, Linjer, et al. [[6]], developed effective and simple synthetic approach to synthesize uniform CoO@meso-CN@MoS SB 2 sb heterostructures to study the photodegradation under a visible light for organic pollutants. Photocatalysis is a highly promising technique to address the challenges of environmental and energy aspects. [Extracted from the article]

• P2-type manganese oxide cathode combines high operating voltage and anionic redox. • Ti gradient modification achieves Ti-enriched surface and Ti-substituted interior. • Gradient modification enhances interfacial stability to reduce side reactions. • Gradient modification mitigates phase transition and irreversible oxygen activity. • Excellent electrochemical performance is obtained at 4.7 V high operating voltage. Constructing layered high-voltage P2-type manganese oxide with working voltage above 4.5 V incorporating into Ni2+/4+ redox and high capacity based on anionic redox has become trend to develop high energy density sodium ion batteries. However, capacity fading and undesired rate capability caused by serious phase transition, irreversible oxygen activity and electrolyte/electrode side reactions would occur especially under high operating voltage besides the Jahn-Teller effect. Here, based on anionic and cationic redox, a novel titanium gradient modification coupling with the synergic Ti-enriched surface and Ti-substituted interior is proposed to achieve excellent stability and rate capability. As a result, the high-voltage P2-Na 0.66 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode induced by titanium gradient modification can deliver a large reversible discharge capacity of 133.2 mA h g−1 with 77.9% capacity retention after 100 cycles under 4.7 V cut-off voltage at 1C (200 mA g−1), and achieve a high energy density of 456.4 Wh kg−1. These outstanding results are attributed to the facts that Ti gradient modification not only is beneficial for suppressing the side reactions and enhancing the interfacial conductivity, but also can modify the lattice structure to improve the structural stability, leading to mitigate the phase transition and irreversible oxygen activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • MC 2 N 4 (M = Cr, Mo, W) monolayers show excellent mechanical and dynamical stabilities. • CrC 2 N 4 exhibits direct bandgap along with strong visible absorption. • All monolayers have suitable band edges for overall photocatalytic water splitting. • CrC 2 N 4 performs better overall water splitting under compressive strain. Recently, the synthesis of 2D MoSi 2 N 4 (Science; 2020;369; 670) proclaimed the dawn of a new family of 2D MA 2 Z 4 materials. In this regard, through first-principles calculations, we proposed novel MC 2 N 4 (M = Cr, Mo, W) monolayers with outstanding stability, which indicates a high possibility for experimental synthesis. The current study reveals that CrC 2 N 4 (2.67 eV) is a direct bandgap semiconductor, whereas MoC 2 N 4 (2.80 eV) and WC 2 N 4 (2.84 eV) are indirect bandgap semiconductors, employing the HSE06 hybrid functional. All monolayers yield suitable band edge positions, making them ideal for photocatalytic water splitting and optoelectronics applications. Interestingly, the CrC 2 N 4 monolayer has strong optical absorption in the visible spectrum. In contrast to MoC 2 N 4 (WC 2 N 4) monolayer, the Young's and layered moduli of the CrC 2 N 4 monolayer are significantly high, 675 Nm−1 and 405 Nm−1, respectively. In contrast MC 2 N 4 (M = Mo, W) monolayers exhibited a highly anisotropic nature compared to CrC 2 N 4. Moreover, strain (+6% to −6%) has played an exciting role in modulating the bandgap and band alignment positions of the MC 2 N 4 (M = Cr, Mo, W) monolayers. Interestingly, compressive strain is more beneficial for the CrC 2 N 4 monolayer to perform photocatalytic water splitting under strong visible light. This work highlights the CrC 2 N 4 monolayer as a novel 2D semiconductor with high stability and excellent photocatalytic properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Facile synthesis of 2D Se-CN nanosheets with one pot, two-step temperature strategy. • N vacancy and Se doping provides a driving force for spatial charge separation. • High S BET 104.1 m2/g and nitrogen defects improves the light-harvesting efficiency. • Se-infused g-C 3 N 4 nanosheets could effectively shorten the electronic path for charge migration. • DFT validates high charge density and active participation of Se in photocatalysis. Graphitic carbon nitride is a promising photocatalyst to address environmental issues and energy applications. Herein, we develop an efficient defect-containing functionalized system of 2D selenium doped g-C 3 N 4 porous nanosheets via one pot with two-step temperature for the first time. During heat treatment, Se-infused g-C 3 N 4 nanosheets loosen stacking and form thinner nanosheets, which could effectively shorten the electronic path of charge migration. The introduction of nitrogen vacancies creates a midgap energy state below the CB, which improves the light-harvesting efficiency. Moreover, the dual effect of N vacancy and Se doping provides a driving force for the dissociation of excitons and achieves an effective spatial charge separation. High specific surface area (104.1 m2/g), suitable bandgap (2.65 eV), and good photocurrent response (0.45 µA cm−2) help to enhance the photocatalytic efficiency of 1-SeCN remarkably. Henceforth, high photocatalytic H 2 production rate of 5441 µmol g−1 h−1 and CO evolution rate of 31.5 µmol g−1 h−1 verifies the effective Se doping enhances the photocatalytic efficiency of g-C 3 N 4. Furthermore, DFT calculations are consistent with experimental results and this facile engineering strategy provides a scalable way to develop a novel, efficient g-C 3 N 4 -based photocatalyst for H 2 production and CO 2 reduction. [ABSTRACT FROM AUTHOR]

The electrochemical detection of Ascorbic acid and dopamine is crucial due to their vital roles in biological processes. Both biomolecules coexist in the human body and have the same oxidation potential, leading to electrode fouling and overlapping of oxidation potential. Accurate detection enables monitoring their levels in biological samples, aiding in disease diagnosis and treatment. This study presents the fast and green synthesis of a highly sensitive and selective electrochemical biosensor for the simultaneous detection of dopamine and ascorbic acid. The change in spherical cluster morphology into nanorods enhances the electrode's electroactive surface area, enhancing sensor sensitivity and selectivity. Electrochemical characterization techniques, including cyclic voltammetry and electrochemical impedance spectroscopy, demonstrated excellent electron transportation and low charge transfer resistance. The sensor exhibited simultaneous detection with a low limit of detection of 8 µM for dopamine and 6.9 µM for ascorbic acid, with a wide linear working range. Additionally, the sensor showed excellent selectivity and repeatability with a vast potential gap at simultaneous detection, making it suitable for clinical and food industry applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C 3 N 4) has emerged as an optimal polymeric material for photocatalysis, electronic assemblies, energy storage and conversion applications. The two dimensional (2D) materials posses exotic electronic properties due to abundant active sites extending the potential use in various technological applications. To realize the advancement from laboratory to industrial use of g-C 3 N 4 a low cost, rapid and large scale production is highly needed. In this work we use microwave-assisted scheme which can overcome these challenges and provide robust, low-cost and scalable approaches to synthesize materials. In present work we designed an innovative method to tailor melamine in microwave reactor by pre-treatment with nitric acid (HNO 3) to obtain porous g-C 3 N 4 nanosheets with a thickness of ~10 nm. This method provides a degree of freedom to tune C to N ratio by just varying the microwave reaction time. The electrochemical properties of the g-C 3 N 4 are performed using nickel foam in KOH electrolyte. The g-C 3 N 4 nanostructures show a specific capacitance of 287 F/g. The electrochemical behavior of pristine g-C 3 N 4 was also measured using Quartz crystal nanobalance and showed a capacitance of 10 F/g. These studies elucidate the electrochemical behavior of g-C 3 N 4 as supercapacitor material. The devised synthesis method will facilitate new pathways for synthesis of 2D g-C 3 N 4 for applications in energy storage and conversion. Image 1 • New microwave synthesis chemistry of g-C 3 N 4 is presented. • 2D porous g-C 3 N 4 with a thickness of ~10 nm is obtained via microwave-assisted method. • Tuning of C to N ratio was obtained by controlling microwave reaction time. • The g-C 3 N 4 nanostructures show a higher specific capacitance of 287 F/g in literature. [ABSTRACT FROM AUTHOR]

MAX phases, characterized as nanolaminates of ternary carbides/nitrides structure, possess a unique combination of ceramic and metallic properties, rendering them pivotal in materials research. In this study, chromium aluminum carbide ternary compounds, Cr2AlC (211), Cr3AlC2 (312), and Cr4AlC3 (413) were successfully synthesized with high purity using a facile and cost-effective sol-gel method. Structural, morphological, and chemical characterization of the synthesized phases was conducted to understand the effects of composition changes and explore potential applications. Comprehensive characterization techniques including XRD for crystalline structure elucidations, SEM for morphological analysis, EDX for chemical composition, Raman spectroscopy for elucidation of vibrational modes, XPS to analyze elemental composition and surface chemistry, and FTIR spectroscopy to ensure the functional groups analysis, were performed. X-ray diffraction analysis indicated the high purity of the synthesized Cr2AlC phase as well as other ternary compounds Cr3AlC2 and Cr4AlC3, suggesting its suitability as a precursor for MXenes production. Additionally, the antimicrobial activity against Candida albicans and biocompatibility assessments against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and HepG2 cell line were investigated. The results demonstrated significant antifungal activity of the synthesized phases against Candida albicans and negligible impact on the viability of E. coli and S. aureus. Interestingly, lower concentrations of Cr2AlC MAX phase induced cytotoxicity in HepG2 cells by triggering intercellular oxidative stress, while Cr3AlC2 and Cr4AlC3 exhibited lower cytotoxicity compared to Cr2AlC, highlighting their potential in biomedical applications. [ABSTRACT FROM AUTHOR]

• ZrSSe/SnX (X = S , Se, S 2 , Se 2) vdWHs possess bandgaps in range of 1.2 to 1.6 eV. • Above mentioned vdWHs show absorption in visible and UV region in range 105 cm−1. • ZrSSe/SnX (X = S , Se, S 2 , Se 2) vdWHs display excellent carrier mobilities (105 cm2 v −1 s −1). Recently, the assembly of novel two-dimensional materials via van der Waals (vdW) interactions to form heterostructures is considered an effective strategy for producing materials with enhanced photocatalytic activities. This study systematically explored the optoelectronic and photocatalytic properties and carrier mobilities of novel ZrSSe/SnX (X = S , Se, S 2 , Se 2) vdW heterostructures using density functional theory. The formation energies, elastic constants, phonon dispersions, and results of ab-initio molecular dynamic simulations indicate structural, mechanical, dynamic, and thermal stability. The electronic band structure and optical properties are calculated using hybrid functional HSE06 for accurate calculations. The results of calculations using the bandgap center technique based on density functional theory show that ZrSSe/SnSe, ZrSSe/SnS 2 , and ZrSSe/SnSe 2 heterostructures possess suitable band edges for photocatalytic overall water splitting. The optical absorption spectrum covers a broad range from 104 in the visible region and increases to 105 in the UV region. Furthermore, the ZrSSe/SnX (X = S , Se, S 2 , Se 2) heterostructures have high carrier mobilities of the order of 105. High mobilities help carriers to move quickly and reduce the recombination rate of holes and electrons. The findings indicate that ZrSSe/SnX (X = S , Se, S 2 , Se 2) heterostructures are potentially efficient visible-light photocatalysts for overall water splitting. [Display omitted] [ABSTRACT FROM AUTHOR]

Nowadays, designing a two-dimensional (2D) van der Waals heterostructure (vdWH) is one of the most promising methods for improving photocatalytic performance and harvesting solar energy. Here, we proposed a novel CrSe 2 /GaN vdWH as an efficient photocatalyst for overall water splitting. The elastic constants, phonon dispersion, and ab-initio molecular dynamics simulation show high mechanical and thermodynamic stability. The HSE06 functional reveals that CrSe 2 /GaN vdWHs possess a direct bandgap. The DFT scheme suggests that the current vdWH belongs to the type-II band alignment and has enough kinetic redox potentials for overall photocatalytic water splitting. The intrinsic electric-field accelerates the photogenerated carrier separation. The carrier mobility of the CrSe 2 /GaN vdWH is observed to be enhanced as compared to the mobility of the CrSe 2 monolayer. Additionally, the optical absorption of the vdWH is found to be high in the visible and ultraviolet regions. The CrSe 2 /GaN vdWH has a high efficiency of solar-to-hydrogen energy conversion (33.41%). The Gibbs free energy shows that the redox reactions (HER & OER) could be sustained under the action of an external electric-field. Finally, the external strain can tune the band edge and optical absorption of the CrSe 2 /GaN vdWH for desired applications. Therefore, the CrSe 2 /GaN vdW heterostructure could be an excellent photocatalyst for water splitting with high solar energy conversion. [Display omitted] • The CrSe 2 /GaN vdW heterostructures possess direct bandgaps. • Exhibited excellent optical absorption capability in the visible and UV regions. • The CrSe 2 /GaN vdW heterostructure shows overall water splitting ability. • Shows a high efficiency of solar-to-hydrogen energy conversion (33.41%). • Gibbs free-energy depicts HER & OER sustained under electric-field (E ext). [ABSTRACT FROM AUTHOR]

To explore the effect of morphology on catalytic properties of graphitic carbon nitride (GCN), we have studied oxygen reduction reaction (ORR) performance of two different morphologies of GCN in alkaline media. Among both, tubular GCN react with dissolved oxygen in the ORR with an onset potential close to commercial Pt/C. Furthermore, the higher stability and excellent methanol tolerance of tubular GCN compared to Pt/C emphasizes its suitability for fuel cells. [ABSTRACT FROM AUTHOR]

We report here the effect of microwave power on the physicochemical and photocatalytic properties of nano-crystalline tin oxide (SnO 2 ) synthesized by using a continuous microwave flow synthesis (CMFS) process. The obtained nanoparticles (Nps) were characterized by using TEM, XRD, FTIR, BET, UV–vis and PL spectra. TEM characterizations revealed that the SnO 2 Nps were agglomerated spheroids. A red shift in energy bandgap (E g ) and a reduction in the photoluminescence (PL) peak intensity were observed on increasing the microwave power. Photocatalytic study confirmed that the synthesized SnO 2 Nps were efficient in degrading methylene blue (MB) dye. SnO 2 NPs with decreased E g have potential to be used in solar cell windows, opto-electronic (UV) devices, UV photo-detector and gas sensing applications. [ABSTRACT FROM AUTHOR]

The MXenes-based two-dimensional (2D) materials have become a hotspot of recent research due to their exciting physical behavior. In this first-principles study, we investigate the Sc 2 TlC MAX phase and its 2D derivatives, focusing on the transformation of Sc 2 TlC into a Sc 2 C 2D sheet and the subsequent surface functionalization of Sc 2 C with oxygen (O) and fluorine (F). Investigations of the electronic structures reveal that the Sc 2 TlC MAX phase is metallic and nonmagnetic, while the conversion to the Sc 2 C pristine monolayer and surface functionalized Sc 2 CO 2 induces significant changes in its electronic structure but retains its metallic behavior. On the other hand, functionalization of the Sc 2 C monolayer with F 2 (such as Sc 2 CF 2) evolves semiconductor-like behavior with an energy gap of magnitude 1.325 eV for the up-spin state and 1.227 eV for the down-spin state. The optimal optical absorption of ultraviolet (UV) for Sc 2 TlC MAX phase and Sc 2 C, Sc 2 CO 2 , and Sc 2 CF 2 MXenes have been found as 13.8 × 105 cm−1, 49.17 × 104 cm−1, 81.39 × 104 cm−1, and 69. ×104 cm−1, respectively. Investigations of the optical properties reveal considerable reflection and absorption capabilities, particularly upon exposure to low-energy light photons, suggesting their potential for optoelectronic and energy harvesting applications. [Display omitted] • First-priciples study of Sc 2 TlC MAX phase, Sc 2 C pristine and Sc 2 CT 2 (T=O, F) surface functionalized MXenes. • Examination of the effect of surface functionalization on physical behavior. • Comprehensive investigations of the changes observed in the electronic structures. • Detailed demonstration of optical properties. • The introduction of surface functionalization using (T= O, F) groups had a notable impact on the electronic features of Sc 2 C MXenes. [ABSTRACT FROM AUTHOR]

In this study, CNNZO (N–ZnO/g-C 3 N 4) nanocomposites were synthesized via a facile hydrothermal method and characterized using XRD, FTIR and FESEM. The resulting N–ZnO nano-needles and plate-like structures, anchored onto g-C 3 N 4 agglomerates, formed distinctive nano-flower topography. CNNZO demonstrated superior photocatalytic activity compared to CN and N–ZnO, achieving ∼98 % degradation of Methylene Blue, 85.53 % of Methyl Green and 87.29 % of Methyl Orange under visible light irradiation within 90 min. This enhanced performance is attributed to the unique morphology of CNNZO, which promotes efficient charge carrier transfer and inhibits recombination. Additionally, CNNZO exhibited improved electrocatalytic activity with smaller HER and OER potentials. This study underscores the potential of CNNZO nanocomposites as effective catalysts for the degradation of organic contaminants and hydrogen and oxygen evolution for energy production. [Display omitted] • Synthesis of N–ZnO/g-C 3 N 4 nanoflowers via template-free hydrothermal method. • Characterization via XRD, FESEM, FTIR and UV–Vis. • Exceptional photocatalytic efficiency for MB, MG and MO degradation. • Displayed HER and OER for energy production. • Promising for photocatalytic and electrocatalytic applications. [ABSTRACT FROM AUTHOR]

The heterojunction of 2D g-C 3 N 4 thin nanosheets and double-shelled ZnSnO 3 nanocubes was prepared via a reliable, convenient, and cost-effective technique to achieve efficient photocatalytic activity. The unique double-layered structure of ZnSnO 3 helps to absorb more visible light and provides a shorter diffusion path for charge carriers. The integration of some wrapped g-C 3 N 4 nanosheets to the outer layer of ZnSnO 3 increases the multiple active sites and specific surface area (S BET) to boost the photocatalytic reaction. The synergistic effect of heterojunction and oxygen vacancies effectively stimulates the generation and spatial charge separation. Furthermore, as-synthesized 2D/3D heterostructure develops an interfacial electric field that plays an efficient role in charge migration and enhances the redox ability of the material. The degradation efficiency for MB (99.5 %, within 30 mins), TC (98.2 %, within 120 mins), H 2 production rate (1799 μmol g−1 h−1) and CO evolution rate (23.6 μmol g−1 h−1) confirms the excellent performance of multifunctional photocatalyst. Additionally, DFT calculations of electronic band structure and density of states are in excellent agreement with experimental results. This work highlights the new perspective on designing suitable nanostructures for photocatalytic applications. [Display omitted] • Synthesis of ZnSnO 3 /g-C 3 N 4 heterojunction to improve the interfacial electric field. • The wrapped g-C 3 N 4 nanosheets provides multiple active sites and high surface area. • Unique double-layered structure of ZnSnO 3 helps to decrease the charge diffusion path. • This synergistic effect of 2D/3D heterojunction stimulates the spatial charge separation. • H 2 production rate is 26.8 and CO evolution rate is 23.6 times greater than pure ZnSnO 3. [ABSTRACT FROM AUTHOR]

Germanium mono-chalcogenides have received considerable attention for being a promising replacement for the relatively toxic and expensive chalcogenides in renewable and sustainable energy applications. In this paper, we explore the potential of the recently discovered novel cubic structured (π-phase) GeS and GeSe for thermoelectric applications in the framework of density functional theory coupled with Boltzmann transport theory. To examine the modifications in their physical properties, the across composition alloying of π-GeS and π-GeSe (such as π-GeS1-xSex for x =0, 0.25, 0.50, 0.75, and 1) has been performed that has shown important effects on the electronic band structures and effective masses of charge carriers. An increase in Se composition in π-GeS1-xSex has induced a downward shift in their conduction bands, resulting in the narrowing of their energy band gaps. The thermoelectric coefficients of π-GeS1-xSex have been accordingly influenced by the evolution of the electronic band structures and effective masses of charge carriers. π-GeS1-xSex features sufficiently larger values of Seebeck coefficients, power factors and figures of merit (ZTs), which experience further improvement with an increase in temperature, revealing their potential for high-temperature applications. The calculated results show that ZT values equivalent to unity can be achieved for π-GeS1-xSex at appropriate n-type doping levels. Our calculations for the formation enthalpies indicate that a π-GeS1-xSex alloying system is energetically stable and could be synthesized experimentally. These intriguing characteristics make π-GeS1-xSex a promising candidate for futuristic thermoelectric applications in energy harvesting devices. [ABSTRACT FROM AUTHOR]

Hierarchical and flower-like nanostructures have attained great attention over the past decades due to their unique and intriguing properties. Considering the advantages of their particular structure and properties, we prepared g-C3N4/MnO2 nanocomposite by microwave heating technique without using any catalysts, templates and organic reagents. The longitudinal and transverse relaxation time of as-synthesized nanocomposites were measured by using 0.55 T MRI instrument. Manganese is the primary origin for MRI and MR signals; therefore, different concentrations of the composite were dissolved in water. Relaxivities were measured by the inverse of relaxation times and plotted against the different concentrations of manganese. MRI results showed that the strength of the imaging signal is directly proportional to the Mn concentration, demonstrating that as-synthesized flower-like nanostructures have excellent T1-weighted MRI performance. This study indicates that the nanocomposite of g-C3N4/MnO2 could be a potential candidate as a bifunctional medical system that combines diagnostic imaging and targeted therapy. [ABSTRACT FROM AUTHOR]

A two step, facile surfactant free hydrothermal route was adopted to synthesize Nb 3 O 7 F novel hollow microflowers (NHMF). Time dependent experiments were performed which suggested Nb 3 O 7 F-NHMF were formed due to Ostwald-ripening process. Raman spectroscopy was conducted to understand different vibrational modes of Nb 3 O 7 F-NHMF. Its characteristic band at 692 cm −1 was observed which is associated to NbO 6 octahedron sharing. The bandgap of 3.2 eV was calculated by using UV-VIS-NIR absorption spectrum. Considering importance of layered structures in energy storage applications, hydrogen storage ability of Nb 3 O 7 F-NHMF were measured for the first time. The maximum values of hydrogen absorption for Nb 3 O 7 F-NHMF at 373 K and 473 K were 0.789 wt.% and 1.08 wt.%, respectively. The hydrogen storage measurements revealed the potential of Nb 3 O 7 F-NHMF as prospective material for energy storage applications. [ABSTRACT FROM AUTHOR]

Abstract: Semiconducting carbon nanotubes are a promising material for nanophotonic applications. The energy bandgap of carbon nanotubes can be tuned by functionalizing it with metal oxides. In this article, the focus is on the substantial reduction of energy bandgap of nanocomposite materials using SnO2/MWCNTs by wet chemistry method. In this method, the MWCNTs are treated with different oxidizing agents and their mixtures in order to generate nucleation sites for the target material particles. The SnO2 nanoparticles were deposited on these nucleation sites by hydrothermal reaction. The energy bandgaps decreased from 3.68eV to 2.93eV for the SnO2/MWCNT nanocomposites. [Copyright &y& Elsevier]

An easy, scalable and environmentally benign chemical method has been developed to synthesize micro strings of graphitic-C3N4 (msg-C3N4) through pre-treatment of melamine with HNO3 in alkaline solvent at low temperature. This methodology results in a unique string type morphology of msg-C3N4 with higher surface area. These msg-C3N4 micro strings were used as a photocatalyst under visible light for photodegradation of rhodamine B, methyl blue and methyl orange. The msg-C3N4 shows enhanced photodegradation efficiency due to its high surface area and favourable bandgap. The first order rate constant for msg-C3N4 was measured which confirms the higher performance of msg-C3N4 in comparison to other reported materials such as g-C3N4, Fe2O3/g-C3N4 and TiO2 nanotubes. Thus, the method developed here is favourable for the synthesis of materials with higher surface area and unique morphology, which are favourable for high photodegradation activity. [ABSTRACT FROM AUTHOR]

Copper vanadate and graphitic carbon nitride (g-C 3 N 4) are pivotal materials in the realm of advanced materials science, owing to their distinctive optical and electronic conductive properties. In the context of environmental photocatalysis and biosensing applications, their synergistic combination holds significant promise. Copper vanadate, renowned for its optical and electronic properties, complements the unique architecture and optical conduction characteristics of g-C 3 N 4. Together, these materials exhibit immense potential for driving advancements in environmental sustainability and diagnostic techniques. In this study, we report the synthesis of copper vanadate (Cu 0.261 V 2 O 5) and its composite with graphitic carbon nitride. XRD confirms the synthesis of the novel phase, FESEM and TEM analysis reveals hierarchical nanoflowers and UV-Visible spectroscopy divulges the visible light activation of the synthesized material and aids in the calculation of the optical bandgap. Interfacial charge transfer was studied with the help of EIS and Mott-Schottky analysis was employed to reveal the semiconductor type (n or p type) and determine the band edges. The as-prepared material was tested for the photocatalytic removal of methylene blue (MB), followed by the study of reaction kinetics, cyclic stability and active radicals participating in the photocatalysis process. The synthesized heterojunction showed 100 % removal of MB within a tenure of 90 minutes. The results of the experiment revealed that Cu 0.261 V 2 O 5 decorated with g-C 3 N 4 displays 1.5 and 1.4 times better photocatalytic degradation capability than pure Cu 0.261 V 2 O 5 and g-C 3 N 4 , respectively. Furthermore, the synthesized material was evaluated for electrochemical biosensing of ascorbic acid in PBS (pH 7) analyte using a 3-electrode system. Compared to the pure material, the heterojunctions drew 1.9 times more current and provided near unity correlation (R2). It is evident that Cu 0.261 V 2 O 5 decorated with g-C 3 N 4 can be implemented for commercial eco-remediation and electrochemical ascorbic acid sensing. [Display omitted] • Synthesis of novel Cu 0.261 V 2 O 5 and g-C 3 N 4 hierarchical nanoflowers for photocatalysis and biosensing. • Characterization via XRD, FESEM, UV-Vis, EIS and Mott-Schottky plot. • Visible light activation and favorable optical bandgap observed. • Exceptional photocatalytic efficiency, outperforming individual constituents. • Electrochemical biosensing for ascorbic acid with near unity correlation R2. [ABSTRACT FROM AUTHOR]

Herein, Strontium Titanate (SrTiO 3) has been synthesized through template-free hydrothermal process and annealed at different temperatures (i.e., 300 °C, 500 °C and 700 °C) in a hydrogen atmosphere to modulate its bandgap. XRD, SEM, UV–Vis spectroscopy and PL spectroscopy were used to characterize the samples. The creation of oxygen vacancies has been verified, which contributes significantly to the reduction of the bandgap and the improvement of photocatalytic efficiency. STO annealed at the temperature of 500 °C displayed maximum evolution of 3060 μmol g−1 of hydrogen gas via photocatalytic water splitting and showed 88% and 81% methyl orange (MO) and methylene blue (MB) degradation, respectively. Furthermore, the as-synthesized materials were used for the electrochemical biosensing of ascorbic acid, and STO-500 showed best results achieving the correlation R-square value of 0.9981. The findings of this study will be useful in investigating SrTiO 3 -photocatalysts in industries and implementing for electrochemical diagnostics. [Display omitted] [ABSTRACT FROM AUTHOR]

Photocatalytic CO2 reduction is a most promising technique to capture CO2 and reduce it to non-fossil fuel and other valuable compounds. Today, we are facing serious environmental issues due to the usage of excessive amounts of non-renewable energy resources. In this aspect, photocatalytic CO2 reduction will provide us with energy-enriched compounds and help to keep our environment clean and healthy. For this purpose, various photocatalysts have been designed to obtain selective products and improve efficiency of the system. Semiconductor materials have received great attention and have showed good performances for CO2 reduction. Titanium dioxide has been widely explored as a photocatalyst for CO2 reduction among the semiconductors due to its suitable electronic/optical properties, availability at low cost, thermal stability, low toxicity, and high photoactivity. Inspired by natural photosynthesis, the artificial Z-scheme of photocatalyst is constructed to provide an easy method to enhance efficiency of CO2 reduction. This review covers literature in this field, particularly the studies about the photocatalytic system, TiO2 Z-scheme heterojunction composites, and use of transition metals for CO2 photoreduction. Lastly, challenges and opportunities are described to open a new era in engineering and attain good performances with semiconductor materials for photocatalytic CO2 reduction. [ABSTRACT FROM AUTHOR]

Summary: Exploring new polymorphs of groups III to V compounds of evolved physical properties has recently received substantial interest from researchers. Accordingly, we explored new pressure‐driven polymorphs of gallium nitride (GaN) and investigated their physical properties using density functional theory (DFT)‐based full‐potential (FP) linearized‐augmented‐plus‐local‐orbital (L[APW + lo]) approach. Our analysis shows the transition of ground‐state wurtzite (wz) structure to beryllium oxide (β‐BeO)‐type structure at a tensile stress of ~−6.82 GPa and to silicon carbide (SiC)‐type structure by applying moderate compressive stress of magnitude 0.27 GPa. Similarly, the transition of wz‐GaN to nickle arsenide (NiAs) and titanium arsenide (TiAs)‐type structures has been realized at 43.78 and 45.72 GPa, respectively. These new polymorphs of GaN exhibited comparable cohesive energies with wz‐structure and the phonon dispersions free of imaginary frequencies, which indicate them as stable as the ground‐state wz‐phase. Investigations of the electronic structures show the wz‐, β‐BeO‐, and SiC‐phases of GaN as semiconductors of direct bandgap of energy 3.10, 3.15, and 2.97 eV, whereas the NiAs‐ and TiAs‐ phases of GaN exhibited indirect bandgap of energy 2.59 and 2.82 eV. All the GaN polymorphs demonstrated transparent behavior for the incident light photon of energy less than 13 eV. They exhibited optical absorption as high as 3.02 × 106 cm−1, 2.23 × 106 cm−1, 2.62 × 106 cm−1, 2.67 × 106 cm−1, and 2.67 × 106 cm−1 in the case of wz‐, β‐BeO‐, NiAs‐, SiC‐, and TiAs‐structured GaN, respectively. These interesting features of the novel polymorphs of GaN indicate them promising for electronic and optoelectronic applications. [ABSTRACT FROM AUTHOR]

Novel nanoflowers (NNF) of Nb3O7F have been synthesized by a facile template free route without using any surfactant. The evolution of these NNF have been studied by varying different reaction parameters. Using the UV-Vis spectra absorption peak the calculated bandgap was 2.9 eV. Organic dye rhodamine B (RhB) was degraded with average photodegradation efficiency of 87.8%, 94.23% and 99.7% with higher rate constant k = 1.1559, 1.9011 and 3.8862 for 0.005 g, 0.01 g and 0.1 g respectively. The rate constant for 0.1 g was found to be larger than for Nb2O5, commercial TiO2 Degussa P25, carbon modified Nb2O5/TiO2, g-C3N4, Fe2O3/g-C3N4 composites and SnNb2O6. [ABSTRACT FROM AUTHOR]

Abstract: Here we report the first ever fabrication of metal/semiconductor Cd/CdO shelled hollow microspheres with average diameter of 20–30 μm via heating cadmium metal powder inside horizontal tube furnace at 500 °C for 40 min under ammonia gas flow of 150 sccm. Vapor-solid (VS) based growth mechanism was proposed for the formation of Cd/CdO shelled hollow microspheres (CCOSHMs). The as-prepared product was characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Room temperature photoluminescence (PL) studies exhibited a UV emission band at 395 nm (E = 3.13 eV) which may be ascribed to combined effect of near band edge emission of CdO and Cd related radiative recombination of electrons in s, p conduction band near Fermi surface and the holes in the d bands generated by Xe light excitation. The hydrogen absorption properties of CCOSHMs were investigated at three different temperatures 373, 473, and 573 K. The maximum hydrogen absorption of 1.30 wt% was observed at 573 K which is better than many other materials. This indicates the potential of Cd/CdO shelled hollow microspheres for applications in light emitting devices as well as an interesting material for hydrogen storage research. [Copyright &y& Elsevier]