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Synthesising and designing pseudocapacitive material with good electrochemical and electrocatalytic behaviour is essential to use as supercapacitor as well as non-enzymatic glucose sensor electrode. In this work, NiCo2 S4 nanoparticles decorated onto the 2D-Carbyne nanosheets are achieved by the solvothermal process. The as-prepared NiCo2 S4 @2D-Carbyne provides rich reaction sites and better diffusion pathways. On usage as an electrode for supercapacitor application, the NiCo2 S4 @2D-Carbyne exhibits the specific capacitance of about 2507 F g-1 at 1 A g-1 . In addition, the fabricated hybrid device generates an energy density of 52.2 Wh kg-1 at a power density of 1.01 kW kg-1 . Besides, the glucose oxidation behaviour of NiCo2 S4 @2D-Carbyne modified GCE has also been performed. The diffusion of glucose from the electrolyte to the electrode obeys the kinetic control process. Furthermore, the fabricated NiCo2 S4 @2D-Carbyne non-enzymatic glucose sensor exhibits a limit of detection of about 34.5 µM with a sensitivity of about 135 µA mM-1 cm-2 . These findings highlight the need to design and synthesis electrode materials with adequate electrolyte-electrode contact, strong structural integrity, and rapid ion/electron transport.

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Semiconductor nanoparticles and nanocrystals have a great impact due to its contribution in the diverse fields including electronics, solar energy, biological imaging, and photonics. Among these semiconductor nanoparticles, cadmium selenide of II-VI group binary semiconductor nanoparticles were synthesized using solvothermal process for the different reaction temperatures. The XRD pattern of the synthesized samples confirms the crystalline nature of the samples and showed increase in its crystallite size with rise in temperature. The morphology of the samples was analysed with TEM images and found that the nanoparticles synthesized at different temperatures were varied in size and shape indicating the increase in the size of the particles with the raise in temperature. The optical properties of the samples pointed out that they exhibit a blue shift owing to quantum confinement. Photocatalytic activity was carried out for the synthesized samples under visible light radiation using methylene blue (MB) as a model pollutant and it proved to be a good photocatalyst achieving the efficiency of 75% which is promising for future application with good optimization. The efficiency could be increased when these semiconductor CdSe nanoparticles are doped with metal particles due to an increase in the absorption edge wavelength and a decrease in bandgap energy were reported in detail.

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Carbon-based materials are promising candidates for enhancing thermal properties of phase change materials (PCMs) without lowering its energy storage capacity. Nowadays, researchers are trying to find a proper porous structure as PCMs support for thermal energy storage applications. In this context, the main novelty of this paper consists in using a ZnO-CNT-based nanocomposite powder, prepared by an own hydrothermal method at high pressure, to obtain porous 3D printed support structures with embedding capacity of PCMs. The morphology of 3D structures, before and after impregnation with three PCMs inorganic salts (NaNO3, KNO3 and NaNO3:KNO3 mixture (1:1 vol% saturated solution) was investigated by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX). For structure impregnated with nitrates mixture, SEM cross-section morphology suggest that the inorganic salts impregnation started into micropores, continuing with the covering of the 3D structure surface and epitaxial growing of micro/nanostructured crystals, which led to reducing the distance between the structural strands. The variation of melting/crystallization points and associated enthalpies of impregnated PCMs and their stability during five repeated thermal cycles were studied by differential scanning calorimetry (DSC) and simultaneous DSC-thermogravimetry (DSC-TGA). From the second heating-cooling cycle, the 3D structures impregnated with NaNO3 and NaNO3-KNO3 mixture are thermally stable.

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BiSCl single-crystalline nanofibers were synthesized by a facile one-pot solvothermal approach for the first time. BiSCl possesses a double chain type structure and grows readily along the c-axis, resulting the fibrous morphology. UV/Vis absorption spectroscopy revealed that BiSCl nanofibers exhibit a strong light absorption in a wavelength range from UV to visible light, corresponding to a bandgap of 1.96 eV. Ultraviolet photoelectron spectroscopy and density functional theory calculations revealed that BiSCl is a direct n-type semiconductor with valence band maximum and conduction band minimum located at 6.04 and 4.08 eV below the vacuum level, respectively. To investigate the photovoltaic performance, the homogeneous thin film of BiSCl-nanorod array was fabricated on a TiO2 porous film by a modified solvothermal process, where the nanorod array is oriented vertically to the surface of the TiO2 porous film. A proper band alignment of BiSCl-based solar cells with an architecture of fluorine-doped tin oxide (FTO)/TiO2 /BiSCl/(I3 - /I- )/Pt gave a PCE of 1.36 % and a relatively large short-circuit photocurrent density of 9.87 mA cm-2 for the first time. The preliminary photovoltaic study result revealed a potential possibility of BiSCl-nanorod array as a light absorber for solar cells that can be fabricated by the low-cost solution process.

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Stability of the photocatalyst, maximum solar energy harvesting and effective photogenerated charge carrier separation are yet demanding key features of the photocatalysis for pollutant abetment and photo-electrochemical applications. Herein, we report the in situ solvothermal synthesis of CdS-Bi2MoO6 core-shell heterostructures (CdS-Bi2MoO6 CSHs) for the photocatalytic elimination of methyl orange (MO) under visible light. The as-synthesized CdS-Bi2MoO6 CSHs exhibited highest photocatalytic performance of 98.5%, which is approximately 10 and 4 folds higher than pristine Bi2MoO6 nanosheets (NSs) and CdS nanorods (NRs), respectively. This significantly enhanced photocatalytic performance is attributed to the core-shell heterostructure that improves the visible-light harvesting ability, facilitates efficient separation and transfer of the photogenerated charge carriers, as well as synergistic band alignment of both CdS NRs and Bi2MoO6 NSs. The CdS-Bi2MoO6 CSHs also showed efficient photocatalytic performance toward methylene blue (MB) as colored dye and tetracycline hydrochloride (TCH) as a colorless emerging contaminant. Additionally, the outcomes of transient photocurrent, electrochemical impedance, and photoluminescence study further corroborate that the construction of core-shell heterostructures with tight contact, leading to effective charge carrier separation. The hole (h+) and superoxide radical anion (•O2-) were determined to be the predominant active species accountable for the MO dye degradation. Furthermore, the CdS-Bi2MoO6 CSHs exhibited a satisfactory recycling efficiency over five cycles (reduced by approximately 6%), owing to the protective Bi2MoO6 NSs shell over the CdS NRs core, demonstrating their applicability in wastewater purification and photo-electrochemical applications.

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Herein, the material structural properties such as phase, morphology, chemical composition, and surface area for In2S3 nanoflakes, synthesized by a one-step solvothermal method, are studied [1]. The comparative electrochemical performance data of indium based electrode material is presented to establish the practical suitability of prepared In2S3 electrode material. Device demonstration of fabricated solid-state supercapacitor device on different time frames set performance level demonstration of current work and suggest a potential candidate for next-generation energy storage electrode material.

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Precise control of the thickness of large-area two-dimensional (2D) organometal halide perovskite layers is extremely challenging owing to the inherent instability of the organic component. Herein, a novel, highly reproducible, and facile solvothermal route is reported to synthesize and tailor the thickness and optical band gap of the organic-inorganic halide perovskite nanosheets (NSs). Our study reveals that self-assembly of randomly oriented perovskite nanorods leads to the growth of multilayered perovskite NSs at ∼100 °C, while at higher temperature, large-area few-layer to bilayer 2D NSs (CH3NH3PbBr3) are obtained through lattice expansion and layer separation depending precisely on the temperature. Interestingly, the thickness of the 2D NSs shows a linear dependence on the reaction temperature and thus enables precise tuning of the thickness from 14 layers to 2 layers, giving rise to a systematic increase in the band gap and appearance of excitonic absorption bands. Quantitative analysis of the change in the band gap with thickness revealed a strong quantum confinement effect in the 2D layers. The perovskite 2D NSs exhibit tunable color and a high photoluminescence (PL) quantum yield (QY) up to 84%. Through a careful analysis of the steady-state and time-resolved PL spectra, the origin of the lower PL QY in thinner NSs is traced to surface defects in the 2D layers, for the first time. A white light converter was fabricated using the composition-tuned 2D CH3NH3PbBrI2 NS on a blue light-emitting diode chip. The 2D perovskite photodetector exhibits a stable and very fast rise/fall time (24 µs/103 µs) along with high responsivity and detectivity of ∼1.93 A/W and 1.04 × 1012 Jones, respectively. Storage, operational, and temperature-dependent stability studies reveal high stability of the 2D perovskite NSs under the ambient condition with high humidity. The reported method is highly promising for the development of large-area stable 2D perovskite layers for various cutting-edge optoelectronic applications.

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Functional carbon material synthesis from waste biomass by a sustainable method is of prime importance and has wide variety of applications. Herein, functional carbon materials with structural variability are synthesized using a well-known solvothermal method. The leftover pulp waste biomass (PB) of citrus limetta is converted to functional carbon by treatment with a mixture of choline bitartrate (ChBt) and FeCl3 (1:2 mol ratio) as a solvent. The biomass to solvent ratio is varied as 1:1, 0.8:1, and 0.4:1 during solvothermal treatment to obtain PB-1, PB-2, and PB-3 as functional carbon materials, respectively. On characterization, PB carbon materials were found to be rich in oxygen-containing functional groups possessing different morphologies. Furthermore, results suggested the role of solvent as a soft template and catalyst during the synthesis of carbon materials. The feasibility of synthesized carbon materials as a biocompatible cosolvent for lysozyme was evaluated. In the case of PB-2 material (synthesized using 0.8:1 biomass to solvent ratio), results show an enhancement of lysozyme activity by 150%. Besides, spectroscopic and calorimetric data confirm the preservation of thermal and structural stability of lysozyme in the PB-2 solution. Thus, this study stipulates PB-2 as an excellent cosolvent for protein studies. With this work, we aim to delve into an entirely new arena of applications of biomass in the field of biotechnology.

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A facile one-pot solvothermal method was applied to synthesize a magnetic biochar composite (MB) using phoenix tree leaves-derived biochar as the carbon matrix. The structure of MB was optimized by varying the load ratio and particle size of Fe3O4 nanoparticles on biochar. Time-dependent structure and composition evolution of solid and liquid phases during heterogeneous solvothermal process were investigated to understand the formation mechanism of MB. Firstly, Fe2+/Fe3+ ions were coordinated by oxygen-containing groups on biochar and part of them were hydrolyzed to form iron hydroxides. Then, those iron-containing precursors were thermally decomposed and reduced to iron oxides; and finally Fe3O4 nanoparticles were generated. The MB had an adsorption capacity for Cr(VI) of 55.0 mg/g in an aqueous solution, which exceeds those of biochar (39.8 mg/g) and Fe3O4 nanoparticles (26.5 mg/g). The adsorption mechanism study reveals that biochar as a carbon skeleton mainly provided binding sites for Cr(VI) and electron-donor groups for reduction of Cr(VI), while Fe3O4 nanoparticles mainly involved in the immobilization of newly formed Cr(III) through formation of Fe(III)-Cr(III) hydroxide. MB exhibited a stable structure with a lower Fe leakage at pH 2.0 than that of a comparable magnetic biochar sample prepared by conventional co-precipitation method. Recycling experiments suggested that MB could keep 84% of its initial removal capability for Cr(VI) even after seven cycles. The results indicate that solvothermal method is a promising alternative to prepare magnetic biochar for adsorption of heavy metal-containing wastewater.

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Organotin compounds have been widely used in recent decades, however, the residential tributyltin (TBT) in environment has potential harmful effects on human health due to the disruption of endocrine system even at trace level. Herein, this work reports on an effective electro-field-assisted-photocatalytic technique for removal of TBT by applying an electric field to photocatalysis of as-prepared hierarchical TiO2 microspheres. The synthesis of catalytic materials is based on a self-assembly process induced by microwave-assisted solvothermal reaction. Hierarchical TiO2 microspheres consisting of nanowires can be obtained in short time with this facile method and possess high surface area and superior optical properties. As the catalyst, it was found that the reaction rate constant of electro-field-assisted-photocatalytic removal (0.0488 min-1) of TBT exhibited almost a 9 fold improvement as compared to that of photocatalysis (0.0052 min-1). The proposed mechanism of electro-field-assisted-photocatalytic removal of TBT was verified by using 117Sn-enriched TBT spike solution as an isotopic tracer. In addition, varying impacts from some key reaction conditions, such as voltage of potential, pH value and the presence of Cr and formaldehyde were also discussed. The overall satisfactory TBT removal performance of the proposed electro-field-assisted-photocatalysis procedure with hierarchical TiO2 microspheres, which was validated using actual tannery wastewater samples from three different kinds of tanning procedures. These attributes suggest that this electro-field-assisted-photocatalysis may have broad applications for the treatment of tannery wastewater.

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The formation of ultralong peptide crystalline nanobelts using a solvothermal approach from a di-phenylalanine gel within 10 min, where the self-assembly process is accelerated by several orders of magnitude compared with the month-long glutaraldehyde induction method previously reported, has been demonstrated. The solvothermal treatment can facilitate the phase separation of di-phenylalanine gels while speeding up the kinetics of the intramolecular cyclization reaction and concomitant crystallization. Moreover, the modulation effect of formaldehyde as an additive is revealed, and that a small amount of formaldehyde leads to thicker crystalline platelets capable of curved optical waveguiding that can potentially be applied in advanced bio-optical and optoelectronic devices, a rare feat with peptide-based crystals.

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Different SnO2 architectures with unitary or binary structure were successfully assembled utilizing the assistance of Polyvinyl pyrrolidone (PVP). The microstructure, surface topography, specific surface area and gas sensing property were investigated with X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET) and WS-60A gas sensing apparatus, respectively. The sensing amplitude, selectivity, response time and recovery time were carefully studied. The possible mechanism of crystallization and gas sensing behavior were also discussed. The present study could be potentially applied to the ethanol or acetone detection and referenced by other researchers and engineers.

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In this study, bismuth oxyhalide (BiOXs (XCl, Br, I)) semiconductors were prepared by a simple solvothermal method, with ethanol serving as solvent and a series of tetrabutylammonium halide surfactants as halogen sources. Under identical synthetic conditions, BiOBr was more readily constructed into regular flower-like hierarchical architectures. The photocatalytic properties of the materials were studied by monitoring the degradation of rhodamine B (RhB), with visible light absorption, and colorless salicylic acid (SA). It was found that both RhB and SA were rapidly degraded on the surface of BiOBr. BiOCl was rather active for the degradation of RhB, but ineffective toward the degradation of SA. However, neither RhB nor SA could be degraded effectively in the case of BiOI. Further experiments such as UV-visible spectroscopy and detection of OH and O2(-) radicals suggest that the electronic structure of the BiOX photocatalysts is responsible for the difference in their activities.

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The Yb(3+) and Er(3+) codoped orthorhombic LuF3 rectangular nanocrystals (NCs) with the size of about 10nm were synthesized by a facile and effective solvothermal process. X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), upconversion (UC) luminescence spectra and decay curves were used to characterize the resulting samples. Compared with YF3 and α-NaYF4 NCs, owning the similar size and the same doping levels of Yb(3+) ions and Er(3+) ions as LuF3 NCs, the green UC emission of LuF3 NCs is 18.7 times and 5.1 times stronger than that of YF3 and α-NaYF4 NCs respectively; the red UC emission of LuF3 NCs is 13.2 times and 0.6 times stronger than that of YF3 and α-NaYF4 NCs respectively. Under 980 nm wavelength excitation, the decay curves of both (4)S3/2→(4)I15/2 transition and (4)F9/2→(4)I15/2 transition exhibit a single exponential function, resulting from the fast energy migrations among Yb(3+) ions caused by the high concentration of Yb(3+) ions (20 mol%). Meanwhile, at relatively low power density, the slopes of the linear plots between log(I) and log(P) for green UC and red UC are 1.7 and 1.9 respectively, which are less than 2 due to the quenching of the thermal effect, indicating a two-photon process for them. At high power density, the slopes are decreased caused by the saturation effect. In addition, we proved the existence of the thermal effect by the pump power dependence of the intensity ratio of (2)H11/2→(4)I15/2 transition to (4)S3/2→(4)I15/2 transition.

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We report here the composition optimization of Zn(x)Fe(3-x)O4 hollow nanospheres for enhancing microwave attenuation. Zn(x)Fe(3-x)O4 hollow nanospheres were synthesized through a simple solvothermal process. The maximum magnetization moment of 91.9 emu/g can be obtained at x = 0.6. The composite filled with Zn0.6Fe2.4O4 exhibited the bandwidth of 3.21-8.33 GHz for RL < -10 dB and a maximum relative bandwidth (Wp,max) of 88.6% at optimized thickness t0 = 0.34 cm. The enhancement should be attributed to the enhanced permeability resonance at high frequency. This optimized hollow material is very promising to be used as a mass efficient and broadband microwave attenuation material.

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Perfluorooctanoic acid (PFOA), an emerging persistent organic pollutant, recently receives worldwide concerns including methods for its efficient decomposition. Three kinds of nanostructured In2O3 materials including porous microspheres, nanocubes and nanoplates were obtained by dehydration of the corresponding In(OH)3 nanostructures at 500 °C for 2 h. The In(OH)3 nanostructures with different morphologies were solvothermally synthesized by using different mixed solvents. As-obtained In2O3 nanomaterials showed great photocatalytic activity for PFOA decomposing. The decomposition rates of PFOA by different In2O3 materials, i.e. porous microspheres, nanoplates and nanocubes were 74.7, 41.9 and 17.3 times as fast as that by P25 TiO2, respectively. The In2O3 porous microspheres showed the highest activity, by which the half-life of PFOA was shortened to 5.3 min. The roles of surface oxygen vacancies on the adsorption and photocatalytic decomposition of PFOA were discussed, and it was found that In2O3 materials with higher oxygen vacancy defects show better activity.

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We review the solvothermal synthesis, using a mixture of ethylene glycol (EG) and water as the solvent, of zinc oxide (ZnO) particles having spherical and flower-like shapes and hierarchical nanostructures. The preparation conditions of the ZnO particles and the microscopic characterization of the morphology are summarized. We found the following three effects of the ratio of EG to water on the formation of hierarchical structures: (i) EG restricts the growth of ZnO microcrystals, (ii) EG promotes the self-assembly of small crystallites into spheroidal particles and (iii) the high water content of EG results in hollow spheres.