Solvothermal Method Research Articles

Rational design of hierarchical porous reduced graphene oxide/9,10-phenanthraquinone/porous carbon nanocomposites for high-performance supercapacitors

The development of advanced electrode material is crucial for promoting the application of new high-performance green energy storage devices and remains a great challenge. Herein, by introducing porous carbon (PC) or carbon nanotubes (CNTs) to further modify the redox-active 9,10-phenanthrenequinone (PQ) molecule non-covalently functionalized reduced graphene oxide (RGO), we have designed and synthesized RGO/PQ/PCs (RPPs) and RGO/PQ/CNTs-10 (RPC-10) nanocomposites using a simple one-step solvothermal method. Benefiting from the optimization of the hierarchical porous nanostructures and each composition further strengthens their respective advantages in the novel synthesized nanocomposites (RPPs and RPC-10), the RPPs and RPC-10 electrodes demonstrated significantly superior electrochemical energy storage performance over the RGO and RGO/PQ (RP) electrodes, especially for the RPP-10 electrode with a high specific capacitance of 343.5 F g−1 at 0.5 A g−1 and good rate capability (69.23%, 0.5−40 A g−1). Furthermore, both the symmetric supercapacitor assembled with the optimal RPP-10 electrode and the hybrid supercapacitor assembled with the RPP-10 negative electrode and the NCSRC-24 positive electrode previously reported show excellent energy densities and ultra-long cycling stabilities. This result demonstrates that the synthesized novel RPP-10 nanocomposite is a highly promising candidate for new light-weight, sustainable, high-flexible and high-performance energy storage devices.

Ppb-level unsymmetrical dimethylhydrazine detection based on In2O3 hollow microspheres with Nd doping

As one of main high-energy fuels for rocket launching, unsymmetrical dimethylhydrazine (UDMH) and its decomposition products do harm to environment and human health. It is significant to develop a device to monitor its leakage. In this work, a UDMH gas sensor based on In2O3 hollow microspheres with Nd dopant was fabricated. The pure, 1.0mol%, 3.0mol% and 5.0mol% Nd doped In2O3 were synthesized via one-step solvothermal method. Among them, 3.0% Nd-In2O3 based sensor exhibits the highest response toward UDMH vapor. Its response value to 100 ppm UDMH is 183.3 at optimal working temperature of 250°C, 6.8 times higher than that of pure In2O3 (26.8). Besides high response to UDMH, the 3% Nd-In2O3 based sensor represents excellent selectivity, rapid response speed (2s) and ultra-low theoretical LOD to UDMH (0.28 ppb). The improved gas sensing performance via Nd doping could be attributed to the enhanced specific surface area, increased concentration of adsorbed oxygen and improved adsorption capacity for UDMH molecular on the surface. The excellent sensing performance of Nd doped In2O3 hollow microspheres makes it a promising candidate for real-time UDMH detection. Environmental ImplicationUnsymmetrical dimethylhydrazine (1,1-dimethylhydrazine, UDMH) is a colorless, highly toxic compound. It has been classified as 2B human carcinogen by the International Agency for Research on Cancer (IARC). The National Institute for Occupational Safety and Health (SLOSH) also regulates the UDMH concentration limitation of 0.06 ppm in workplace. Therefore, it is urgent to fabricate a device for detecting the UDMH leakage timely during its storage and transport. In our work, Nd doped In2O3 hollow microspheres based chemiresistive gas sensor for the monitoring of UDMH was developed, which will promote the practical applications for gas sensor.

Adsorption of Thorium (IV) from Aqueous Solutions Using Mesoporous TiO2: Kinetics, Isotherm and Thermodynamics

Thorium is considered as a promising resource for the production of nuclear power, with its abundance in the Earth's crust offering potential for sustainable energy generation to fulfill upcoming energy needs. As a fertile material, thorium has the capability to be converted into fissile uranium-233, which is essential for sustaining nuclear chain reactions. Therefore, the extraction of thorium from the Earth's crust is imperative for its utilization as fuel in nuclear reactors. This study presents the synthesis of Titanium dioxide with a mesoporous structure using the solvothermal method for extracting Th(IV) from aqueous solutions. Batch adsorption experiments were carried out to evaluate the impact of solution pH, adsorption kinetics, adsorbent dosage, initial Th(IV) concentration, and temperature. The adsorption process is influenced by the pH, showing a maximum adsorption capacity of 101.4 mg per gram of mesoporous TiO2 adsorbent (MTA) at an initial Th(IV) concentration of 400 mg L−1 and pH 4.0. Results indicate a significant correlation with the pseudo-second-order and Freundlich adsorption isotherm models. Temperature-dependent investigations revealed that the adsorption of Th(IV) is spontaneous at room temperature and increases with higher temperatures (endothermic process). Moreover, the study highlights the rapid kinetics of Th(IV) adsorption by MTA, making it a favorable choice for upscaling the extraction process of Th(IV). In conclusion, the results suggest MTA as a promising adsorbent for the removal of Th(IV) from aqueous solutions.

Size Control of Carbon Xerogel Spheres as Key Factor Governing the H2O2 Selectivity in Metal-Free Bifunctional Electro-Fenton Catalysts for Tetracycline Degradation

Carbon xerogel spheres co-doped with nitrogen and eco-graphene were synthesized using a typical solvothermal method. The results indicate that the incorporation of eco-graphene enhances the electrochemical properties, such as the current density (JK) and the selectivity for the four transferred electrons (n). Additionally, nitrogen doping has a significant effect on the degradation efficiency, varying with the size of the carbon xerogel spheres, which could be attributed to the type of nitrogenous group doped in the carbon material. The degradation efficiency improved in the nanometric spheres (48.3% to 61.6%) but decreased in the micrometric-scale spheres (58.6% to 53.4%). This effect was attributed to the N-functional groups present in each sample, with N-CNS-5 exhibiting a higher percentage of graphitic nitrogen (35.7%) compared to N-CMS-5 (15.3%). These findings highlight the critical role of sphere size in determining the type of N-functional groups present in the sample. leading to enhanced degradation of pollutants as a result of the electro-Fenton process.

Improved properties of CoFe2O4@rGO/PVDF composites prepared through a solution-mixing approach

In this work, a hybrid material based on CoFe2O4 nanoparticles immobilized on reduced graphene oxide (CoFe2O4@rGO) was successfully synthesized through a one-step green solvothermal method. Subsequently, the resultant CoFe2O4@rGO was further modified by aminopropyltriethoxysilane to form the A-CoFe2O4@rGO hybrid, serving as the filler of poly(vinylidene fluoride) (PVDF). The facile preparation of A-CoFe2O4@rGO was confirmed through various microstructural characterization techniques. PVDF-based composites with varying contents of A-CoFe2O4@rGO (1 wt%, 3 wt%, 5 wt%, 7 wt%, and 10 wt%) were prepared using a solution-mixing approach. SEM results revealed uniform distribution of the A-CoFe2O4@rGO filler within the PVDF matrix. The XPS results indicated an obvious interfacial interaction between the A-CoFe2O4@rGO filler and PVDF matrix. Consequently, the crystallization degree and β crystalline content of PVDF matrix in the A-CoFe2O4@rGO(7 wt%)/PVDF composite were enhanced to 52.3 % and 32.1 %, respectively, compared to 42.2 % and 26.0 %, respectively, in pure PVDF. The A-CoFe2O4@rGO(10 wt%)/PVDF composite enhanced electrical conductivity and dielectric constant at 100 Hz, with values of 1.33 × 10−7 S/m and 22.1, respectively, compared to 1.86 × 10−9 S/m and 8.6, respectively, in pure PVDF. In addition, despite the non-magnetic nature of pure PVDF, the A-CoFe2O4@rGO(10 wt%)/PVDF composite possessed a magnetization value of 1.64 emu/g at 60,000 Oe. The comprehensive enhancement in crystallization behavior, electrical, dielectric, and magnetic properties demonstrates the potential of the A-CoFe2O4@rGO/PVDF composite for various applications.

Au- ZnFe2O4 hollow microspheres based gas sensor for detecting the mustard gas simulant 2-chloroethyl ethyl sulfide.

Mustard gas, a representative of blister agents, poses a severe threat to human health. Although the structure of 2-chloroethyl ethyl sulfide (2-CEES) is similar to mustard gas, 2-CEES is non-toxic, rendering it a commonly employed simulant in related research. ZnFe2O4-based semiconductor gas sensors exhibit numerous advantages, including structural stability, high sensitivities, and easy miniaturization. However, they exhibit insufficient sensitivity at low concentrations and require high operating temperatures. Owing to the effect of electronic and chemical sensitization, the gas-sensing performance of a sensor may be remarkably enhanced via the sensitization method of noble metal loading. In this study, based on the morphologies of ZnFe2O4 hollow microspheres, a solvothermal method was adopted to realize different levels of Au loading. Toward 1 ppm of 2-CEES, the gas sensor based on 2 wt.% Au-loaded ZnFe2O4 hollow microspheres exhibited a response sensitivity twice that of the gas sensor based on pure ZnFe2O4; furthermore, the response/recovery times decreased. Additionally, the sensor displayed excellent linear response to low concentrations of 2-CEES, outstanding selectivity in the presence of several common volatile organic compounds, and good repeatability, as well as long-term stability. The Au-loaded ZnFe2O4-based sensor has considerable potential for use in detecting toxic chemical agents and their simulants.

Synthesis and characterization nitrogen-doped carbon dots from candlenut shells using hydrothermal and solvothermal methods

Synthesis and characterization nitrogen-doped carbon dots from candlenut shells using hydrothermal and solvothermal methods

Garnet-based solid state batteries benefitting from an ionic/electronic mixed conductive interface constructed by lithiation of porous FeS2

Garnet-based solid-state lithium metal batteries are considered as the potential candidates for the next-generation energy storage systems due to their high energy density, wide operating temperature, and high safety. However, the poor wettability of the lithium metal anode/garnet interface, the large interface resistance, and the risk of lithium dendrites growing and even penetrating electrolytes during cycling limit the practical application of garnet-based solid-state lithium metal batteries. In this work, a porous network FeS2 with an amorphized structure is prepared by using the solvothermal method and used as the Li/garnet interface modification layer. The porous FeS2 can be in situ converted into a Li2S/Fe mixed conductive layer by the thermal lithiation of molten metallic lithium. This mixed conductive layer can significantly reduce the interface resistance, ensure the close contact between Li and garnet, and inhibit the growth of lithium dendrites. The interface resistance of the modified Li/FeS2-LLZTO (LLZTO is Li6.5La3Zr1.5Ta0.5O12) interface at 60 °C is as small as 15.20 Ω cm2. The ionic conductivity of fully lithiated FeS2 is estimated to be 1.58 × 10−6 S cm−1 at room temperature. The Li/FeS2-LLZTO/Li symmetrical cell can cycle stably for more than 400 h at a high current density of 400 μA cm−2, with the voltage polarization of only about 25 mV, and can withstand a larger current density of 600 μA cm−2 without the polarization exceeding 50 mV. These results demonstrate the feasibility of in situ lithiation of porous iron sulfide into a mixed ion/electron conductive layer as a solid-state garnet interface modification strategy and provide the new interface method for the development of high-performance solid-state lithium metal batteries.

Comparing The Catalytic Activity of Mg-BTC Metal Organic Framework and Post Synthetically Modified (TiO2 @ Mg-BTC) Metal Organic Framework for Cyanosilylation of Aldehydes

Metal organic frameworks (MOFs) are an emerging class of porous crystalline hybrid materials synthesised by the coordination of inorganic connectors and organic linkers, which has numerous potential applications in various fields. Here we report a comparative study on Mg-BTC MOF and TiO @Mg-BTC MOF as a heterogeneous catalyst. Mg-BTC MOF was synthesised by solvothermal method and subjected to comparative study with its post synthetically modified (PSM) counterpart to understand their catalytic behaviour for cyanosilylation of aldehydes. The synthesised Mg-BTC MOF and TiO @Mg-BTC MOF were characterised by powder XRD, BET surface area, SEM, FT-IR, TGA techniques. A detailed characterization study was performed to understand the correlation between catalytic activity and morphology of the assynthesized MOF and PSM-MOF. The catalytic activity of the hybrid materials were evaluated by GC-MS analysis. The results of the catalytic reactions revealed that post synthetically modified (TiO @Mg-BTC) MOF exhibited significantly higher catalytic activity compared to Mg-BTC MOF. The enhanced catalytic efficiency is due to the incorporation of TiO nanoparticles, which provides active sites for catalytic reactions under heterogeneous conditions. Even after repeated recycling and reuse, the catalytic ability of the catalyst retains. The impact of TiO on the framework shows variation in texture, surface area, thermal stability and catalytic behaviour on the MOF materials. Thus, our study emphasizes

Co3O4/RGO Nanoparticles Fabricated by Facile Solvothermal Method as an Anode Material for High‐Performance Lithium‐Ion Batteries

AbstractA potential anode material for lithium‐ion batteries (LIBs), Co3O4 has been widely considered by many scholars because of its excellent properties in terms of electrochemical characteristics and theoretical specific capacity. However, according to the existing research results, we found that the improvement of the electrochemical performance of Co3O4 has encountered a bottleneck because its intrinsic conductivity is not high enough, and more importantly, the volume expansion is too significant during the charge and discharge process, which leads to the material structure breaking. Therefore, this paper proposes a simple and scalable solvothermal and subsequent calcination method to prepare Co3O4 and reduced graphene oxide (RGO) composite nanoparticles with superior microstructures, and their morphological and electrochemical properties were investigated at different calcination temperatures. As a high‐performance anode material for lithium‐ion batteries, the Co3O4/RGO nanoparticles obtained at 550 °C exhibited terrific initial discharge capacity of 1714.2 mAh g−1, the reversible specific capacity of 1191.9 mAh g−1 with quality coulombic efficiency 98.17 % at 0.5 A g−1 after 100 cycles and extraordinary rate performance (907.6 mAh g−1 with a coulombic efficiency of 99.2 % at 2 A g−1). The facile synthesis method and excellent findings have led to better application prospects for Co3O4/RGO nanoparticles.

An ultrasensitive NO2 gas sensor based on a NiO-SnO2 composite with a sub-ppb detection limit at room temperature

The highly sensitive detection of ppb-level NO2 at room temperature (RT, 25 °C) remains a challenge hindering the detection of metal oxides due to their chemical inactivity. Herein, a strategy for constructing mixed metal oxides with high specific surface areas and highly active surfaces is proposed. In this work, we synthesized NiO-SnO2 using the solvothermal and calcination methods with Ni/Sn bimetallic organic frameworks (Ni/Sn-BTC MOFs, BTC: benzene-1,3,5-tricarboxylic) as sacrificial templates. The characterization shows that NiO-SnO2 has a high porosity (0.343 m3/g) and a large specific surface area (74.73 m2/g), which can produce abundant permeability pathways for NO2, maximize the number of active sites, and enhance the capacity for NO2 capture. The sensing test results indicate that the NiO-SnO2 sensor exhibits an excellent sensing response of 693.1% (ΔR/Ra) to 150 ppb NO2, a fast response/recovery time (86.8/29.4 s), a distinct selectivity, a lower detection limit (25 ppb) and good long-term stability at RT and 60% RH (RH: relative humidity). The outstanding sensing performance can be attributed to the microstructure characteristics, oxygen vacancies and p-n heterojunctions formed between NiO and SnO2. The current work provides a versatile platform for designing sensitive materials with heterogeneous structures and opens up a new pathway for the development of room temperature gas sensors based on metal oxide.

Carbon-coated (Eu/Dy-Enabled) erbium hydroxide nanostructures for biomedical imaging

Lanthanides possess versatile optical and magnetic properties, making them an excellent candidate for multimodal imaging. This study focuses on carbon-coated Erbium Hydroxide Nanoparticles (Er(OH)3 NPs), their cytotoxicity, and their potential for biomedical imaging. Er(OH)3 NPs were synthesized via a simple solvothermal method with the incorporation of different lanthanide dopants (Eu, Dy) to enhance the optical and magnetic properties. The spherical morphology, monodispersity, elemental composition, and effective carbon coating were demonstrated using characterizations such as SEM, EDS, and DLS. These monodisperse NPs were further evaluated for their cytotoxicity in Hep2c cervical cancer cells via colorimetric assays, thus proving carbon coating effectively reduces the cytotoxicity. Photoluminescence data of these NPs show multiple emission peaks with a maximum peak at 433 nm when excited at 253 nm. Magnetic resonance imaging (MRI), and computed tomography (CT) scans of these NPs were carried out to evaluate the multimodal imaging potential as contrast agents. The CT contrast shows comparable results to those of iodine-based contrast agents while the MRI scans of the carbon-coated samples show T2-weighted contrast. These findings provide insights into the potential use of Lanthanide-Enabled Er(OH)3 NPs (LEENs) as multimodal contrast agents.

Microwave‐assisted Fast Synthesis of a Donor‐Acceptor Covalent Organic Framework towards Photooxidative Amidation Catalysis

The synthesis of covalent organic frameworks (COFs) at bulk scale require robust, straightforward, and cost‐effective techniques. However, the traditional solvothermal synthetic methods of COFs suffer low scalability as well as requirement of sensitive reaction environment and multiday reaction time (2‐10 days) which greatly restricts their practical application. Here, we report  microwave assisted  rapid  and optimized synthesis of a donor‐acceptor (D−A) based highly crystalline COF, TzPm‐COF in second (10 sec) to minute (10 min) time scale. With the increasing of the time from seconds to minutes crystallinity, porosity and morphological changes are also observed for TzPm‐COF. Owing to visible range light absorption, suitable band alignment, and low exciton binding energy (Eb=64.6 meV), TzPm‐COF can efficaciously produce superoxide radical anion (O2•−) after activating molecular oxygen (O2) which eventually drives aerobic photooxidative amidation reaction with high recyclability. This photocatalytic approach works well with a variety of substituted aromatic aldehydes having electron‐withdrawing or donating groups and cyclic, acyclic, primary or secondary amines with moderate to high yield. Furthermore, catalytic mechanism was established by monitoring the real‐time reaction progress through in‐situ diffuse reflectance infrared Fourier transform spectroscopic (DRIFTS) study.

Microwave-assisted Fast Synthesis of a Donor-Acceptor Covalent Organic Framework towards Photooxidative Amidation Catalysis.

The synthesis of covalent organic frameworks (COFs) at bulkscalerequire robust, straightforward, andcost-effective techniques. However, the traditional solvothermal synthetic methods of COFs suffer low scalability as well as requirement of sensitive reaction environment and multiday reaction time (2-10 days) which greatly restricts their practical application. Here, we report microwave assisted rapid and optimized synthesis of a donor-acceptor (D-A) based highly crystalline COF, TzPm-COF in second (10 sec) to minute (10 min) time scale. With the increasing of the time from seconds to minutes crystallinity, porosity and morphological changes are also observed for TzPm-COF. Owing to visible range light absorption, suitable band alignment, and low exciton binding energy (Eb=64.6meV),TzPm-COF canefficaciously produce superoxide radical anion (O2•-) after activating molecular oxygen (O2) which eventually drives aerobic photooxidative amidation reaction with high recyclability. This photocatalytic approach works well with a variety of substituted aromatic aldehydes having electron-withdrawing or donating groups and cyclic, acyclic, primary or secondary amines with moderate to high yield. Furthermore, catalytic mechanism was established by monitoring the real-time reaction progress through in-situ diffuse reflectance infrared Fourier transform spectroscopic (DRIFTS) study.

Facile and efficient synthesis of sweater-ball shaped metal-organic framework/nickel sulfide nanoheterojunction for boosting electrochemical glucose sensing

The synthesis of heterojunction materials is regarded as an efficient way to enhance catalytic activities in various catalytic reactions. However, the existing fabrication approaches often rely on complex multi-step synthesis process. In this work, we fabricate sweater-ball shaped nanostructured MOF/TMS (Ni-MOF/NiS1.03) heterojunction by one-pot, one-step solvothermal method. According to the results of discrete Fourier transform (DFT) calculations and experiments, the formation of Ni-MOF/NiS1.03 heterojunction interfaces improves electron transfer and charge redistribution, and increases the adsorption energy of glucose molecules as well, which is conducive to enhance electrochemical activity of electrode materials. The as-prepared Ni-MOF/NiS1.03 heterojunction exhibit enhanced glucose sensitivity, wide detection range and low detection limit. This study paves the way towards the development of MOF-based heterojunctions for electrochemical applications.

Tuning benzene activity of cobalt-based spinel catalysts with cation substitution

Cobalt-based spinel oxides are promising low-cost catalysts for volatile organic compounds (VOCs) elimination. Herein, we prepared the cobalt-based spinel oxides (MCo2O4: M = Ni, Cu, Co, Zn) by a one-step solvothermal method to evaluate the influence of cation substitution on benzene combustion. The cation distribution on tetrahedral and octahedral sites could influence the degree of inversion in cobalt-based spinel oxides, thus achieving the regulation of Co-O bond strength. NiCo2O4 catalyst with the inverse spinel structure had the weak Co-O bond strength, which is conducive to the activation of lattice oxygen to improve the activity of benzene degradation. This work provides deep insights into the influence of the cation substitution on the cobalt-based spinel catalysts for the efficient benzene oxidation.

Two Cd(Ⅱ)/Mn(Ⅱ) complexes based on multinuclear metal clusters for Fe(Ⅲ) and Cr(Ⅵ) fluorescence detection and magnetic properties

Two novel complexes, {[Cd3(L)2(H2O)2]·(H2O)4}n (1) and {[Mn(HL)(H2O)2]·(H2O)}n (2), which are synthesized by the reaction of 3-(2, 4-dicarboxyphenyl)-4-carboxypyridine ligand with cadmium and manganese metal ions under the solvothermal method. The complex 1 is a 3D framework based upon trinuclear [Cd3(μ2-COO)4(μ1-COO)4(N)2] SBUs, and the complex 2 is a one-dimensional metal oxygen chain based upon binuclear [Mn2(μ2-COO)2(μ1-COO)2(N)2] SBUs. The solid fluorescence analysis of complex 1 reveals that the emission peak of 451 nm when its excitation peak is 336 nm. The fluorescence detection experiments of complex 1 showed that Fe3+, Cr2O72− and CrO42− can effectively to be detected. Furthermore, their limits of detection are 1.47 × 10−3 M, 1.31 × 10−3 M and 1.25 × 10−3 M, respectively. It has good recovery properties as a potential multifunctional fluorescence sensor. Besides, the quenching mechanism of fluorescence sensing is also discussed. In addition, the magnetic studies of complex 2 show strong antiferromagnetic interactions between its neighboring Mn(II) ions.

Fabrication of CZS NRs/NiSx NPs hybrids with abundant S-vacancies for signally promoting photocatalytic hydrogen production

The cocatalysts play a key role in photocatalytic technology in remarkably improving the efficiency of H2 evolution. Herein, S vacancies-rich Cd0.6Zn0.4S nanorods (CZS NRs) were prepared via solvothermal method. Then, as-obtained CZS NRs were modified with Ni–Co PBA-derived NiSx nanoparticles (NPs) cocatalyst using grinding method. The optimized CZS/NiSx-N-1.5 hybrids (CZS/NiSx-N, where N represents nickel nitrate which was used as nickel source) exhibited outstanding stability and activity, the average rate of H2 was up to 192.82 mmolg−1h−1 in deionized water medium, which was 201.4% higher than that of CZS. Besides, NiSx-A and NiSx-C cocatalysts with different particle sizes were obtained using nickel acetate (A) and nickel chloride (C) as nickel source, respectively. The CZS/NiSx-C-1.5 and CZS/NiSx-A-1.5 exhibited the H2 evolution rate of 180.70 and 201.93 mmolg−1h−1 in deionized water medium, respectively. The as-prepared materials also exhibited the excellent H2 evolution performance in natural seawater medium. Besides, the photocatalytic mechanism of H2 evolution over CZS NRs/NiSs NPs was also discussed. This work develops a novel H2 evolution cocatalyst and unveils the relationship between the loading amount/particle size of cocatalyst on the H2 evolution rate.

Effect of Bi doping in tuning the structural, morphological and optoelectronic properties of solvothermally synthesized SnS nanorods

In this work, enhanced optoelectronic properties of SnS is attained through the substitutional doping of Bi into the SnS lattice at the ‘Sn’ sites by following cost effective solvothermal method at a reaction temperature of 170 °C for a duration of 90 min. The charge states explored through XPS analysis revealed the existence of the constituent elements in Sn2+, S-Sn2+ and Bi3+ states. The chemical structure investigated through Raman analysis revealed the successful doping of Bi into orthorhombic SnS without affecting its phase purity for doping up to 12 %. With increasing the doping up to 4 %, (a) the shift in 2θ peak position to the higher angle side and the contraction in unit cell volume as evident from XRD analysis ensured the substitutional doping of Bi3+ into Sn2+ sites and (b) the direct energy band gap and electrical resistivity are reduced from 1.60 to 1.30 eV and 719×103 to 627×102 Ω cm respectively and the carrier concentration is enhanced from 1.22×1012 to 8.92×1013 cm−3 revealing the optimum doping of Bi into SnS is 4 %. Due to the effect of doping, the homogeneity in size and shape of the nanorods is enhanced with an increase in size as evident from HR-TEM analysis. The electrical transport properties obtained from Hall measurement studies showed p-type conductivity for SnS with Bi doping up to 10 %. Hence, this report provides the first experimental confirmation for the absence of any carrier polarity conversion in phase pure SnS due to the incorporation of Bi.

Microstructure regulation of Zn0.5Cd0.5S for enhancing the photocatalytic H2 production

As an excellent photocatalytic material, ZnxCd1-xS is widely used in photocatalytic H2 production due to its good visible light response and suitable band position. Based on our previous studies, this paper systematically studies the relationship of Zn0.5Cd0.5S (ZCS) material between microstructure and photocatalytic activity. By controlling the synthesized temperature, S sources and solvents, a series of ZCS nanomaterials with different morphology and crystalline phase have been prepared by hydrothermal, solvothermal and ion-exchange methods. When several sacrificial agents are added in photocatalytic H2 production, ZCS performs the highest activity synthesized by solvothermal method, about 12.15 mmol g−1 under 4 h’s visible light illumination. To explore the difference of ZCS samples in photocatalytic performance, many factors are considered, such as crystal size, crystallinity, separation of photogenerated charge carriers (PCCs), specific surface area and defect sites, which play important roles in the improving photocatalytic activity. This work provides a new direction for the design of photocatalyst from the microstructural regulation to achieve highly efficient activity.