Co-Catalyst Ti3C2TX MXene-Modified ZnO Nanorods Photoanode for Enhanced Photoelectrochemical Water Splitting

In order to obtain a high photoelectrochemical performance, co-catalysts loading is the most commonly used way, which can facilitate reactions and suppress the charge recombination. In this paper, a novel composite of ZnO/Ti₃C₂T_X photoanode was fabricated by a facile spin coating of precipitating Ti₃C₂T_X (MXene) flakes onto the surface of ZnO, as co-catalyst for enhanced photoelectrochemical (PEC) water splitting. Under simulated sunlight, the optimum composite of ZnO/Ti₃C₂T_X photoanode showed the photocurrent density as 1.2 mA cm^?2 at 1.23 V_RHE, which is 1.4 times higher than that of pristine ZnO without Ti₃C₂T_X co-catalyst (0.83 mA cm^?2 at 1.23 V_RHE). The ZnO/Ti₃C₂T_X photoanode showed a photoconversion efficiency of 0.32% and maintained a stable photocurrent over 2000s. The Ti₃C₂T_X (MXene) flakes as co-catalyst to promote the charge transfer and accelerates the reaction kinetics in ZnO/Ti₃C₂T_X photoanode. This work delivers a two-dimensional (2D) material Ti₃C₂T_X (MXene) as co-catalyst for enhanced ZnO photoanode PEC water splitting.

     

Intermediate temperature electrical properties in 4 mol% ZnO-doped Zr0.92Y0.08O2-α/NaCl-KCl composite electrolyte

In this paper, 4?mol% ZnO-doped Zr_0.92Y_0.08O_2-α (8YSZ) and its 8YSZ+4ZnO/NaCl-KCl composite electrolyte were synthesized by a solid-state reaction. The X–ray diffraction (XRD) analysis indicates that 8YSZ+4ZnO and inorganic chlorides phases can coexist. The inorganic chlorides decrease the synthesis temperature of 8YSZ+4ZnO. The highest conductivities of 8YSZ+4ZnO and 8YSZ+4ZnO-NK are 7.0?×?10^?3 S?cm^?1 and 7.7?×?10^?2 S?cm^?1 at 700?°C, respectively. The oxygen concentration discharge cell shows that 8YSZ+4ZnO and 8YSZ+4ZnO-NK are good oxide ionic conductors under an oxygen-containing atmosphere. Finally, an H₂/O₂ fuel cell based on the 8YSZ+4ZnO-NK electrolyte reached the maximum power density (P_max) of 315.5?mW?cm^?2 at 700?°C.     

Effect of Au ion beam on structural,surface, optical and electrical properties of ZnO thin films prepared by RF sputtering

In the present work, ZnO thin films were irradiated with 700?keV Au⁺ ions at different fluence (1?× 10¹³, 1?× 10¹⁴, 2?× 10¹⁴ and 5?× 10¹⁴ ions/cm²). The structural, morphological, optical and electrical properties of pristine and irradiated ZnO thin films were characterized by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), scanning electron microscope (SEM), spectroscopy ellipsometry (SE) and four point probe technique respectively. XRD results showed that the crystallite size decreased from pristine value at the fluence 1?×?10¹³ ions/cm², with further increase of ion fluence the crystallite size also increased due to which the crystallinity of thin films improved. SEM micrographs showed acicular structures appeared on the ZnO thin film surface at high fluence of 5?×?10¹⁴ ions/cm². FTIR showed absorption band splitting due to the growth of ZnO nanostructures. The optical study revealed that the optical band gap of ZnO thin films changed from 3.08?eV (pristine) to 2.94?eV at the high fluence (5?× 10¹⁴ ions/cm²). The electrical resistivity of ZnO thin film decreases with increasing ion fluence. All the results can be attributed to localized heating effect by ions irradiation of thin films and well correlated with each other.     

Stabilizing nanocrystalline Cu2O with ZnO/rGO: Engineered photoelectrodes enables efficient water splitting

The engineered photoelectrodes have received significant attention in the photoelectrochemical (PEC) applications. Herein, we prepared a highly effective photoelectrode based on Cu₂O decorated with ZnO and rGO for efficient PEC water splitting. Firstly, different thickness Cu₂O is sputtered on the FTO substrate (FC). The PEC performance of the FC photoelectrode further improved by depositing the ZnO and rGO protection layers (FCZG). The fabricated photoelectrodes are systematically investigated for their morphological and crystal structure by AFM, FESEM, TEM, XPS, XRD, and RAMAN, UVDRS, and PL analysis. The FCZG hybrid photoelectrode exhibit a photocurrent density of 4.94 mA cm^?2 at 0 V vs. reversible hydrogen electrode (RHE), which is 1.5 times higher than the unmodified photoelectrodes. The improved PEC performance of the FCZG hybrid photoelectrode is due to the high surface roughness, larger electrochemical active surface area, and less radiative recombination rate of the photogenerated charge carriers.     

Growth of silver nanowires on carbon fiber to produce hybrid/waterborne polyurethane composites with improved electrical properties

One dimensional silver nanowires (AgNWs) were grown on carbon fiber (CF) by a facile polyol method. Fourier transform infrared spectrometer (FTIR), laser Raman spectrometer (Raman), field‐emission scanning electron microscopy (FESEM), X ray diffraction instrument (XRD), energy dispersive spectrometer (EDS), and X‐ray photoelectron spectrometer (XPS) were carried out to reveal the structure, morphology, and formation mechanism of the CF‐AgNWs. It was found that AgNO₃ concentration of 1.5 mM, reaction temperature of 160°C, and reaction time of 120 min were appropriate conditions for growth of AgNWs on CF. Moreover, a mechanism was suggested that the cysteamine on CF acted as nucleation centers for growth of silver nanoparticles and then small sized silver nanoparticles reduced from silver nitrate were grown on CF via the silver bonding to sulfur. Through an Ostwald ripening process, small sized silver nanoparticles were grown into larger particles. With the assistance of polyvinylpyrolidone (PVP), these larger particles were directed to grow in a definite direction to form nanowires. It was found that the resistance of CF‐AgNWs was decreased to 19.5 Ω, compared with that of CF (102.6 Ω) with the same quality. Thus, the CF‐AgNWs was added into waterborne polyurethane (WPU) to improve the electrical and dielectric properties of WPU. Results showed the WPU/CF‐AgNWs composite presented a lower percolation threshold than WPU/CF composite. When the content was 2.5 wt %, the volume resistivity of the WPU/CF‐AgNWs (1.90 × 10⁴ Ω cm^?1) was lower by approximately three orders of magnitude than that of WPU/CF (4.19 × 10⁷ Ω cm^?1). When the content was 2.5 wt %, the dielectric constant and dielectric loss of the WPU/CF‐AgNWs were improved to 15.24 and 0.21, which were 34.5 and 40.8% higher than that of WPU/CF. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43056.     

Swelling behavior of polyelectrolyte complex hydrogels composed of chitosan and hyaluronic acid

Polyelectrolyte complex (PEC) hydrogels composed of various weight ratios of chitosan and hyaluronic acid were prepared. The PEC hydrogels were formed by the reaction of the oppositely charged chitosan polymers. The PEC films swelled in water rapidly, reaching equilibrium within 30 min, and exhibited relatively high swelling ratios, 243–322%, at 25°C. The swelling ratio increased with increasing temperature. The transport phenomena of all PEC samples were non‐Fickian and diffusion and relaxation controlled. The diffusion coefficients of the PEC films ranged from 2.22 × 10^?6 to 10.05 × 10^?6 cm²/s. The activation energy of the polyelectrolyte complexes ranged from 37.14 to 54.58 kJ/mol and proved to be hydrophilic. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1097–1101, 2004     

Hydrothermal deposition of AgCl/AgBr co-sensitizers to modify TiO2 NTs for enhanced photocatalytic performance

AgCl/AgBr co-sensitizers were prepared on TiO₂ nanotube arrays (TiO₂ NTs/AgCl/AgBr) by the hydrothermal method. The composition, morphology, optical absorption, photoelectric and photoelectrocatalytic (PEC) performances of TiO₂ NTs/AgCl/AgBr were influenced by the concentration ratio of KCl/KBr. The investigation results revealed that the TiO₂ NTs/AgCl/AgBr photocatalyst exhibited dramatically strong visible light absorption and outstanding photoelectrochemical capacity. The photoelectrode produced high visible light surface photovoltage (-0.43 V), transient photocurrent (0.47 mA/cm²) and carrier concentration (4.39 × 10²⁰ cm^-3). The sample also showed high PEC activity in the organic dye and Cr(VI) removal, and the photocatalytic mechanism and charge carrier transfer path were described based on PEC results. The investigation would offer prospective insight to the sensitization of TiO₂ NTs, which would result in extensive attraction in the preparation and application of semiconductor materials as photoelectrodes and photocatalysts with superior photoelectrochemical performances.     

High carrier mobility low-voltage ZnO thin film transistors fabricated at a low temperature via solution processing

Wide-bandgap ZnO TFTs have many potential applications in large-area, flexible electronics and transparent devices because of their low cost, high performance and excellent optical transmittance. High-performance ZnO TFTs fabricated via simple solution processing have been widely studied. However, the key issues of solution-processable ZnO TFTs are the relatively high processing temperature (> 300?°C) and the high operating voltage for achieving the desired electrical properties. Here, we successfully fabricated low-voltage ZnO TFTs at an annealing temperature of ≤?250?°C. The resulting ZnO transistors with high-k terpolymer P(VDF-TrFE-CFE) showed a mobility of up to 5.3?cm² V^?1 s^?1 and an on/off ratio of >?10⁵ at 3?V. Furthermore, the influence of the dielectric constant on the carrier mobility was investigated. A lower k-value dielectric resulted in a high carrier mobility under the same carrier density. Therefore, with a low-k CYTOP dielectric applied to modify the interface between the ZnO semiconductor and the P(VDF-TrFE-CFE) layer, ZnO transistors annealed at 250?°C showed an electron mobility of 13.6?cm² V^?1 s^?1 and an on/off ratio of >?10⁵ at 3?V. To the best of our knowledge, this mobility is the highest value reported to date among the low-voltage solution-processable undoped ZnO TFTs annealed at temperatures of ≤?300?°C.     

Nanoparticules Mass Effect of ZnO on the Properties of Poly(4-Chloroaniline)/Zinc Oxide Nanocomposites

4-Chloroaniline (4ClAni) in the presence of zinc oxide (ZnO) nanoparticles were prepared by chemical oxidative polymerization in hydrochloric acid solution using Ammonium persulfate as oxidant. The effects of amount of ZnO nanoparticles (1, 1.5, 2, 2.5 and 3 g, respectively) on the properties of products were investigated. The obtained nanocomposites was characterized using XRD, IR, UV–visible, and XPS which confirmed the incorporation of the nanoparticle ZnO in the P(4ClAni) matrix and the maximum interaction occurs for 2 g ZnO loading. The TGA analysis was used to confirm the thermal stability and number of water molecules in each nanocomposites chain unit. Although the incorporation of ZnO nanoparticles reduces the electric conductivity of the P(4ClAni), the resulting nanocomposites still keep high conductivities, ranging between 2.19 × 10^?2 and 5.92 × 10^?4 S cm^?1. Good electrochemical response has been observed for samples of amounts ZnO less than 2 g; the observed redox processes indicate that the polymerization on ZnO nanoparticles produces electroactive polymers. The P(4ClAni) layer adhered well to the ZnO nanoparticles and can be used as practical applications.     

Improving the fabrication uniformity of ZnO nanowire UV sensor by step-corner growth mode

Uniformity in mass-fabrication of nanostructured device is important for its practical application. In this paper, we developed a step-corner growth mode to on-chip fabricate uniform oblique-bridged ZnO nanowire UV sensor. By strictly controlling the microelectronic processing including photolithography and magnetron sputtering procedures during the seed layer deposition and electrode fabrication, ZnO NW array could nucleate at the upper step-corner of the seed layer due to the high catalytic activities at the surface steps and kinks, and then grow in a distribution of circular sector to form an oblique bridging configuration, which guaranteed the device performance and uniformity at the same time. For the within-chip uniformity, in a 4?×?4 sensor array that randomly chosen under the 365?nm UV light of 2.5?mW/cm² and at the bias voltage of 1?V, the light-to-dark current ratio all kept in the level of 10⁶ with the average value of 1.84?×?10⁶. There were 75% of them in the range of 1.1?×?10⁶ ~ 3?×?10⁶. The detectivity all kept in the level of 10¹⁵Jones with the average value of 3.53?×?10¹⁵Jones. There were 75% of them in the range of 2?×?10¹⁵ ~4?×?10¹⁵Jones. For the chip-to-chip uniformity, in 12 packaged devices that randomly chosen from three fabrication lots, the light-to-dark current ratio all kept in the level of 10⁶ with the average value of 2.70?×?10⁶. There were 75% of them in the range of 1?×?10⁶~ 3?×?10⁶. The detectivity all kept in the level of 10¹⁵Jones with average value of 3.69?×?10¹⁵Jones. There were 75% of them in the range of 1?×?10¹⁵ ~ 4?×?10¹⁵Jones. The uniformity would deteriorate if the step height of seed layer was short, because NW would nucleate at the lower corner of the step and difficult to form the oblique bridge. Fabrication uniformity was also influenced by the step exposure degree, the compactness of the seed layer and the flatness of the substrate.     

Morphological exploration of chemical vapor–deposited P-doped ZnO nanorods for efficient photoelectrochemical water splitting

Photoelectrochemical (PEC) water splitting is beneficial and has received attractive attention due to a greater potential to generate hydrogen and oxygen from water by using plentiful solar light to solve the problem of energy crisis. Various active semiconductor materials are used in PEC water splitting applications. Nevertheless, in past decades, most of the researchers suggested that titanium oxide (TiO₂) is the best photoanode for this type of applications. Now, Zinc oxide (ZnO) is considered a perfect substitution to TiO₂ due to its comparable energy band structure and superior photogenerated electron transfer rate. In this study, bare and phosphorous-doped ZnO nanorods were successfully developed on fluorine-doped tin oxide-coated glass (FTO) substrate by chemical vapor deposition. X-ray diffraction (XRD) pattern authenticated hexagonal structure formation with strong diffraction peak of (101), which showed that ZnO nanorods were perfectly developed along c axis. The optical and morphological properties were analyzed by UV–Vis and scanning electron microscopy images. The energy-dispersive X-ray spectra demonstrated that doping agent phosphorous was present in ZnO nanorods. The PEC properties of the developed ZnO nanorods were further investigated and obtained results suggested that a small amount of phosphorous-doped ZnO nanorods enhances their PEC performance.     

Silanization of ZnO nanofibers by tetraethoxysilane

Zinc oxide (ZnO) nanofibers are synthesized by electrospinning technique and then silanized to tailor its structural, optical, and electrical properties. The modification of ZnO nanofibers by chemical treatment of tetraethoxysilane (TEOS) is clearly evident from the appearance of relevant Fourier transform infrared peak at about 1000 cm^?1 corresponding to Zn? O? Si bond. The height of this peak increases linearly with increase in concentration of silane up to 400 μL, and afterward become plateau up to 500 μL. Diffuse reflectance spectroscopy measurement shows that band gap decreases from 3.35 eV for pure zinc oxide nanofibers to 3.11 eV with successive increase in concentration of TEOS from 100 to 500 μL. The electrical characteristics of modified ZnO nanofibers are analyzed by impedance spectroscopy. It is observed that impedance of ZnO nanofibers increases (resistance from 1.69 × 10⁸ to 2.618 × 10⁹ ohm and capacitance from 2.043 × 10^?12 to 7.618 × 10^?13 F) with increase of TEOS concentration. This study provides guidelines for tailoring the electrical properties of ZnO nanofibers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45378.     

Antibacterial efficiency of alkali-free bio-glasses incorporating ZnO and/or SrO as therapeutic agents

A series of seven alkali-free silica-based bioactive glasses (SBG) with ZnO and/or SrO additives (in concentrations of 0–12?mol%) were synthesized by melt-quenching, aiming to delineate a candidate formulation possessing (i) a coefficient of thermal expansion (CTE) similar to the one of titanium (Ti) and its medical grade super-alloys (crucial for the future development of mechanically adherent implant-type SBG coatings) and (ii) antibacterial efficiency, while (iii) conserving a good cytocompatibility. The SBGs powders were multi-parametrically evaluated by X-ray diffraction, Fourier transform infrared and micro-Raman spectroscopy, dilatometry, inductively coupled plasma mass spectrometry, antibacterial (against Staphylococcus aureus and Escherichia coli strains) suspension inhibition and agar diffusion tests, and human mesenchymal stem cells cytocompatibility assays. The results showed that the coupled incorporation of zinc and strontium ions into the parent glass composition has a combinatorial and additive benefit. In particular, the “Z6S4” formulation (mol%: SiO₂—38.49, CaO—32.07, P₂O₅—5.61, MgO—13.24, CaF₂—0.59, ZnO—6.0, SrO—4.0) conferred strong antimicrobial activity against both types of strains, minimal cytotoxicity combined with good stem cells viability and proliferation, and a CTE (~?8.7?×?10^?6 ×?°C^?1) matching well those of the Ti-based implant materials.     

The effect of sintering atmospheres on the properties of CSBT-0.15 ferroelectric ceramics

Ca_0.15Sr_1.85Bi₄Ti₅O₁₈ (CSBT-0.15) ferroelectric ceramics were developed by the conventional solid-state reaction method under various sintering atmospheres. The influences of these sintering atmospheres on grain orientation, grain size, oxygen vacancies, ferroelectric properties and leakage mechanisms were systematically investigated. It was found that the samples sintered under N₂ showed higher a-axis orientation and smaller grain sizes than those sintered under O₂ and air. From XPS analysis, it can be observed that the amount of Ti³⁺ in the ceramics sintered under N₂ is relatively high, which indicates a high number of oxygen vacancies in these samples. The samples sintered under N₂, air and O₂ all delivered well-saturated hysteresis loops with a remnant polarization (2Pr) of 13.8?μC/cm², 12.4?μC/cm² and 7.2?μC/cm² and corresponding coercive fields (2Ec) of 100?kV/cm, 86?kV/cm and 80?kV/cm, respectively. At 70?kV/cm, the leakage current densities of the samples sintered under N₂, air and O₂ are 4.2?×?10^?6 A/cm², 1.9?×?10^?6 A/cm² and 1.0?×?10^?6 A/cm², respectively. The leakage conduction mechanism transformed from Ohmic conduction in a relatively low applied electric field range (0–15?kV/cm) to space-charge-limited conduction (SCLC) in higher electric field ranges.     

Sol-gel processed high-k aluminum oxide dielectric films for fully solution-processed low-voltage thin-film transistors

High-k oxide dielectric films have attracted intense interest for thin-film transistors (TFTs). However, high-quality oxide dielectrics were traditionally prepared by vacuum routes. Here, amorphous high-k alumina (Al₂O₃) thin films were prepared by the simple sol-gel spin-coating and post-annealing process. The microstructure and dielectric properties of Al₂O₃ dielectric films were systematically investigated. All the Al₂O₃ thin films annealed at 300–600?°C are in amorphous state with ultrasmooth surface (RMS ~ 0.2?nm) and high transparency (above 95%) in the visible range. The leakage current of Al₂O₃ films gradually decreases with the increase of annealing temperature. Al₂O₃ thin films annealed at 600?°C showed the low leakage current density down to 3.9?×?10^?7 A/cm² at 3?MV/cm. With the increase of annealing temperature, the capacitance first decreases then increases to 101.1?nF/cm² (at 600?°C). The obtained k values of Al₂O₃ films are up to 8.2. The achieved dielectric properties of Al₂O₃ thin films are highly comparable with that by vapor and solution methods. Moreover, the fully solution-processed InZnO TFTs with Al₂O₃ dielectric layer exhibit high mobility of 7.23?cm² V^?1 s^?1 at the low operating voltage of 3?V, which is much superior to that on SiO₂ dielectrics with mobility of 1.22?cm²/V^?1 s^?1 at the operating voltage of 40?V. These results demonstrate that solution-processed Al₂O₃ thin films are promising for low-power and high-performance oxide devices.     

Electrochemical,spectroscopic and molecular docking studies of 4-methyl-5-((phenylimino)methyl)-3H- and 5-(4-fluorophenyl)-3H-1,2-dithiole-3-thione interacting with DNA

Cyclic voltammetry (CV) and UV–Visible spectroscopy (UV–Vis) techniques were used to calculate binding parameters of 4-methyl-5-((phenylimino)methyl)-3H-1,2-dithiole-3-thione (MPDT) and 5-(4-fluorophenyl)-3H-1,2-dithiole-3-thione (FPDT) with DNA. The results obtained from both techniques were confirmed by computational molecular docking using AutoDock molecular docking software. The anodic peak potential shift in CV indicated an intercalative mode of binding. The binding constants (M^?1) of the adducts MPDT-DNA and FPDT-DNA obtained from voltammetric measurements were found to be 8.0?×?10⁴ and 2.4?×?10⁴, respectively, with binding free energy being ?27.99 and ?25.01?KJ?mol^?1, respectively. These results are in good agreement with those obtained from UV–Visible spectroscopic studies. The diffusion coefficients of MPDT and FPDT (2.06?×?10^?10 and 2.42?×?10^?9, respectively) were found to be higher than those of DNA-bound compounds (1.27?×?10^?10 and 1.65?×?10^?9?cm²/s, respectively). The binding free energy of MPDT and FPDT to DNA was also calculated by molecular docking study. The docking study gave excellent approximation with experimental results, shedding light on the sites of binding.     

Reduction of sulphur in PbSPbCl2NaCl melts

The reduction of dissolved sulphur and the soluble species formed during the electrolysis of PbS dissolved in the PbCl₂NaCl eutectic has been studied chronopotentiometrically. The pre-lead reduction process reported earlier[1] can now be assigned to a subsulphide species that is generated electrochemically. At higher PbS concentrations (eg 10^?3 mol cm^?3), elemental sulphur introduces a new reduction wave in addition to the subsulphide. The saturation solubility of sulphur is approximately proportional to the square of the PbS concentration. It has been estimated to be 2.3× 10^?4 mol S cm^?3 at 430°C for a melt containing 2.4× 10^?3 mol PbS cm^?3 in the PbCl₂-NaCl eutectic.     

Kinetic Study of the Photoexcited Triplet State of Free Base Porphyrins by EPR

An electron paramagnetic resonance (EPR) study of the photoexcited triplet state of four free base porphyrins is presented. The zero field splitting parameters (ZFS) |D| and |E| were calculated from the EPR spectra of the porphyrins dissolved in n-octane matrices at 80°K. |D| = 0.0359 cm^?1, |E| = 0.0079 cm^?1 for tetra phenyl porphyrin (H₂ TPP), |D| = 0.0432 cm^?1, |E| = 0.0037 cm^?1 for tetra (per-fluoro) phenyl porphyrin H₂T (per-F) PP, |D| = 0.0366 cm^?1, |E| = 0.0078 cm^?1 for tetra (para-chloro) phenyl porphyrin H₂T(P-Cl)PP, |D| = 0.0369 cm^?1, |E| = 0.0076 cm^?1 for tetra (para-methyl) phenyl porphyrin H₂T(P-Me)PP. The transient behavior of the EPR signal intensities in the last two porphyrins is discussed. The depopulation rate constants of the triplet sublevels k_p, the ratio between the population rate constants A_p (at zero field, p = x,y,z), and the spin lattice relaxation rate W within the triplet manifold, were calculated. k_x = (12 ± 2) × 10² sec^?1, k_y = (0.5 ± 0.1) × 10² sec^?1, k_z = (1.2 ± 0.4) × 10² sec^?1, A_x:A_y:A_z ? 0.63:0.01:0.33, W = (0.4 ± 0.1) × 10⁴ sec^?1 for H₂T(P-Cl)PP, k_x = (7 ± 2) × 10² sec^?1, k_y = (4 ± 1) × 10² sec^?1, k_z = (1.5 ± 0.5) × 10² sec^?1, A_x:A_y:A_z ? 0.56:0.31:0.13, W = (1.7 ± 0.4) × 10³ sec^?1 for H₂T(P-Me)PP.     

Solution transformation of SnS into Cu2ZnSnS4xSe4(1-x) for solar water splitting

Cu₂ZnSnS_4xSe_4(1-x) (CZTSSe) has recently attracted much attention for solar water splitting due to its high absorption efficient and tunable bandgap. However, high quality CZTSSe thin films with good quality and adherence with the substrate are mainly based on physical deposition method, such as magnetron sputtering, which is expensive and energy consuming processes. Here, we have developed a novel and low-cost solution fabrication method and CZTSSe electrodes were synthesized at low temperature by hydrothermal treatment of chemical bath deposited SnS films. The quality and phase purity of CZTSSe thin films were greatly improved after annealing process and the effect of SnS thickness to the physical and photoelectrochemical (PEC) properties of CZTSSe thin films were detailedly studied. The fabrication of FTO/CZTSSe/CdS/TiO₂/Pt photocathode improved the PEC properties of CZTSSe thin films greatly and the highest water splitting photocurrents of 7.2 mA/cm⁻² had been achieved under simulated solar illumination. Furthermore, the electrode showed good stability and had a good incident photon-to-current efficiency (IPCE) response in the visible light range.     

Investigation of layered perovskite NdBa0.5Sr0.25Ca0.25Co2O5+δ as cathode for solid oxide fuel cells

Layered perovskite oxides with and without Ca-doped NdBa_0.5Sr_0.25Ca_0.25Co₂O_5+δ (NBSCaCO) and NdBa_0.5Sr_0.5Co₂O_5+δ (NBSCO) are studied to investigate the effects of Ca doping on the crystal structure, thermal behavior, electrical and electrochemical properties. Both NBSCO and NBSCaCO are tetragonal structure with P4/mmm space group. The average thermal expansion coefficient (TEC) value is reduced from 23.3?×?10^?6 K^?1 to 19.8?×?10^?6 K^?1 during 30–800?°C. The electrical conductivities are increased by Ca doping. Both electrical conductivities of NBSCO and NBSCaCO are higher than 600?S·cm^?1 over 30–800?°C. Substitution of Sr with Ca can effectively improve the electrochemical properties of NBSCaCO. From 650?°C to 800?°C, the area specific resistance (ASR) of NBSCaCO are decreased from 0.62 to 0.062?Ω?cm² and the corresponding output power density are increased from 258 to 812?mW?cm^?2. On the basis of these results, Ca doped layered perovskite NBSCaCO can be a good cathode candidate material for SOFC application.