To investigate the effect of cation disorders to modulate thermoelectric performance of Cu3SbSe4 system, we attempted to tune copper content in Cu3+xSbSe4 (x = -0.06, -0.04, 0, 0.04, 0.06, and 0.08) system synthesized via solid-state reaction route. Considering the asymmetry in charge and phonon transport properties, intentional deviations from the proper stoichiometry successfully enhance the electrical transport and reduce the phonon transport simultaneously. The self-doping effect induced by the off stoichiometry in Cu3SbSe4 provides acceptor levels, thereby elevating the electrical conductivity. Modulating the Fermi level within the valence band, we could realize a power factor to the highest value of ∼232 µW/mK2 for the sample with x = -0.06 at 210 K. Considerable reduction in thermal conductivity is the key factor in enhancing the figure of merit to a maximum value of ∼0.033 (at 350 K) for the sample with x = 0.06, which about three times higher than that of the pristine sample. The present study demonstrates that non-stoichiometry plays a substantial role in modulating the thermoelectric transport of the Cu3SbSe4 system.

Mesoporous photoanodes, as quantum dot adsorption framework and electron transfer paths, are the key components in efficient quantum dot-sensitized solar cells (QDSSCs). Binary heterojunction mesoporous photoanodes hold promise for facilitating electron transport due to the heterojunction potential, when compared to conventional mono-component mesoporous photoanodes. In this work, we construct a binary mesoporous photoanode with enhanced mesoporous and electron transport using a BaSnO3-SnO2 heterojunction, and then fabricated CdSe/CdS co-sensitized QDSSCs. The charge extraction, open-circuit voltage decay, electrochemical impedance spectroscopy, and intensity-modulated voltage/photocurrent spectroscopy measurements demonstrated that, in contrast to the BaSnO3 mesoporous photoanode, the BaSnO3-SnO2 mesoporous photoanode could effectively reduce charge recombination and extend the electron lifetime, thus promoting charge collection in the QDSSCs. Based on these merits, the BaSnO3-SnO2 mesoporous photoanode-based solar cells yielded a power conversion efficiency of 3.14%, resulting in a ca. 11% increase in power conversion efficiency, compared to the reference BaSnO3 solar cells.

Tuning the electronic structure is fundamental to improve the optical character and redox ability of photocatalysts. Thus, in this article, g-C3N4 with sodium and oxygen co-doping and cyano groups (NOCCN) was successfully synthesized by a brief one-step thermopolymerization. The results indicate that introduction of sodium and oxygen dopant and cyano groups bring a narrower band gap for NOCCN, adjust the overall electronic structure of NOCCN in the positive direction, and facilitate more efficient electron migration ability, which promoted NOCCN achieving photocatalytic water splitting oxygen evolution rate of 1.26 mmolh−1 g − 1 without the assistance of any co-catalyst. Furthermore, DFT calculation and related experimental results was also combined to confirm the chemical structure of NOCCN. Obviously, this paper provides a feasible tactic to inflect the electronic construction of g-C3N4, improving its oxidizing ability.

The dimension of semiconductor nanostructures is an effective parameter in their applications as photocatalysts, catalysts, sensors, etc. This effect of semiconductor nanostructures is more significant in heterostructures with different applications. In detail, we investigate the dimensional effect of ZnO nanostructures on the contact interface type of heterostructures and the number of created electron transfer channels at the contact place. In this work, heterostructures were designed and prepared by merging one component with fixed dimension (2D g-C3N4) and one component with variable dimension (0D ZnO, 1D ZnO, 2D ZnO, and 3D ZnO). Then, the accuracy of their structure was confirmed by various analyzes such as SEM, TEM, XRD, XPS, and Raman. Also, the charge transfer efficiency and photocatalytic properties were explored via electrochemical study, optical analysis, and photocatalytic tests for the degradation of organic pollutants. Examining the effect of dimension parameters on the interface area and charge transfer properties of carbon-based heterostructures showed that the heterostructures with more interface area create higher transfer channels for electron transfer to the surface and provide greater charge transfer efficiency. Among the prepared heterostructures with different dimensions, the 2D-2D heterostructure with more interface area between the two components has more electron transfer channels on all over of contact interface (surface-to-surface contact) and trapped more charge on the surface; thus, it shows a higher charge transfer efficiency and photocatalytic properties.

Metal chalcogenides and carbonaceous composites have triggered enormous interest in the field of high-performance supercapacitors due to their lower electrical resistance and high specific capacitance. Herein, nanocomposites between Sn, Se, and SnSe argan-derived carbon were prepared via a simple hydrothermal process. The porosity and the electrochemical activity of carbon were enhanced by the incorporation of SnSe into the carbon matrix. These materials were employed as supercapacitor electrodes in a symmetric configuration using 6M KOH as electrolyte. The galvanostatic charge-discharge (GCD) test revealed that AC/SnSe has the highest specific capacitance of 341 F·g–1 at a current density of 1 A·g–1. While the EIS measurements showed that the equivalent series resistance dropped from 11.8 Ω for AC to just 0.69 Ω in the case of AC/SnSe which explains its excellent electrochemical performance. Moreover, the stability test showed excellent stability for AC/SnSe with a capacitance retention of 96 % after 5000 cycles was achieved. In addition, the AC/SnSe electrode delivered an energy density of 45.5 W h Kg–1 at a power density of 54.3 W Kg–1. The excellent performance of AC/SnSe electrode can be attributed to its high surface area, large pore volume, and its layered structured that enhances the ionic adsorption.These findings suggest that the prepared AC/SnSe nanocomposite seems to be feasible as electrode material in the supercapacitor field or any related electrochemical application.

The influence of organic dyes in polypyrrole (PPy) preparation has been significantly manifested in the change of its morphology and increase in conductivity. The addition of Acid Blue 25 (AB25) and Acid Blue 129 (AB129) during the electrosynthesis of pyrrole supports the modification of PPy morphology (forming fibers and smaller globular size structures, respectively) and led to a switch in PPy electrochemical behavior as well as stability. PPy-AB25 exhibits higher electroactivity, capacitance, and diffusion – controlled capacitive contribution than PPy-AB129.

Solid oxide fuel cells (SOFCs) require simple cell fabrication procedure and reduced sintering temperature to improve system economics and durability. In this work, we propose a one-step low temperature (950 °C vs. conventional ≥1300 °C) sintering technology to prepare doped ceria electrolyte-based SOFCs by adding 3 mol% of Li2O sintering aid. Super low temperature sintering grants the direct application of nanoporous Ni-based cermet anode and hierarchical SrNb0.1Fe0.9O3 cathode with improved catalytic activities, which improves SOFC efficiency. The ionic conductivity of the electrolyte and catalytic activities of electrodes are systematically investigated by the electrochemical impedance spectroscopy technique and analyzed by the distribution of relaxation time method. These electrolyte-supported SOFCs exhibit an OCV value of 1.01 V at 500 °C and a peak power density of 291 mW cm−2 at 700 °C as well as sufficient stability for 50 h. Our results demonstrate a reliable and affordable method for manufacturing high-performance SOFCs.

In this paper, Ag nanoparticles were deposited on the surface of nitrogen-doped titanium dioxide coupled with manganese-substituted phosphomolybdic acid composites (N-TiO2/Mn-HPMo) using photoreduction method to construct ternary photocatalysis-Fenton composite catalyst (N-TiO2/Mn-HPMo/Ag), and the degradation performance of the catalyst was evaluated with Rhodamine B (RhB) as the target pollutant. The results showed that the N-TiO2/Mn-HPMo/Ag ternary composite catalyst had remarkable visible light activity, and the degradation efficiency of RhB could reach 96.3% in 20 min under visible light. Meanwhile, UV–vis diffuse reflectance spectroscopy illustrated the promotion effect of Ag deposition on the visible light response of N-TiO2/Mn-HPMo. The behavior of photogenerated charges was also characterized by Surface Photovoltage Technique, which further demonstrated that Ag deposition not only extended the light absorption range but also enhanced the separation efficiency of photogenerated charges. This work provides favorable information for the construction of efficient catalysts with high activity under visible light.

Redox mediators (RMs) have been considered by far the most effective strategy to lower the huge charge polarization of Li-O2 batteries, which is caused by the sluggish electrochemical oxidization of discharge products Li2O2. However, the RMs can not only restrict at the cathodic side but also shuttle to the lithium (Li) anode and further react with it, leading to unexpected degradation of both cathodes and anodes, thereby compromising the sustainability of the battery. Herein, we have developed a MOF-decorated glass fibers as separator (HUKST-1/GF) which is capable of suppressing the I–/I3– redox shutting involved in Li-O2 batteries. The interstices of the MOF are compact with optimal pore size, thus acting as an effective sieve to hinder the transference of the I3–. Moreover, the prepared separator possesses high ionic conductivity (1.35×10−3 S cm−1) and Li+ transference number (0.46). As a result, the Li-O2 batteries based on HUKST-1/GF separators exhibit exceptional electrochemical performance compared with those employing traditional separators.

Simultaneous water purification of multiple hazardous pollutants assisted by photocatalysis technology is regarded as an environmentally friendly and energy-smart strategy under the background of energy and water crisis. Herein, a Z-scheme heterojunction of TiO2-Au@CN nanofibers was constructed. The CB and VB with high potentials were maintained due to the merit of Z-scheme heterojunction. By simultaneous excitement of TiO2 and CN, the TiO2-Au@CN composites presented excellent photocatalytic performance for coinstantaneous 86% inactivation rate against E.coli and 93% RhB removal within 60 min under simulated solar light irradiation. The promoted photocatalytic performance probably resulted from Z-scheme electron transfer mechanism at the interface of the heterojunction assisted by AuNPs as an electron mediator. Moreover, the photocatalytic degradation and disinfection process mainly occurred at surface active sites separately on CB from CN and VB from TiO2, respectively. The constructed Z-scheme heterojunction with efficient light utilization showed great potential in practical water purification under sunlight.

Antibiotics have been observed in industrial and domestic wastewater due to the extensive utilization of pharmaceuticals, demonstrating a considerable threat to aquatic ecosystems and human health. In this research, novel MnCo2O4 nanoparticles (NPs) accommodated on porous TiO2 networks were prepared by sol-gel approach for tetracycline (TC) degradation. TEM images revealed that the MnCo2O4 NPs (5–10 nm) was accommodated on mesoporous anatase TiO2 (20–30 nm). The 3% MnCo2O4/TiO2 photocatalyst displayed the maximum photocatalytic ability among the synthesized samples, including commercial P-25 and pristine TiO2, which indicated a high photocatalytic activity of 100% within 60 min of illumination time. The rate constants (k) values revealed that 3%MnCo2O4/TiO2 nanocomposite was 0.0479 min−1, which was about 18.4 and 47.9 folds greater than that of TiO2 NPs and P-25. The increased photocatalytic performance of MnCo2O4/TiO2 was ascribed to extending visible light response and promoting separation rate of electron-hole. Additionally, the unique mesostructured with the high surface area provided an abundant active site and outstandingly reduced MnCo2O4 aggregation. Meanwhile, the synthesized 3%MnCo2O4/TiO2 photocatalyst displayed excellent stability after five cycles. The photocatalytic mechanism over the heterojunction MnCo2O4/TiO2 nanocomposites was addressed in detail. The obtained mesostructure photocatalyst with a large surface area through this reasonable procedure strategy can significantly degrade and mineralize the organic contaminants in industrial and domestic wastewater under visible light.

Compositionally graded ferroelectrics (CGFEs) have attracted great interest due to their exceptional and tunable electromechanical properties, which are anticipated to be superior to traditional ferroelectrics. However, an effective design of CGFEs with desired properties from a huge compositional space remains an enormous challenge. In this study, we present an efficient design strategy for CGFEs through a combination of high-throughput phase-field simulation and machine learning (ML) algorithm. Systematic phase-field simulations are first performed to establish a dataset of electromechanical properties for various CGFEs, which are characterized by three degrees of freedom, including compositions of two end materials and gradient index. A ML-assisted optimization process is then conducted on this dataset to yield optimal electromechanical properties, which are further analyzed by phase-field simulations. The ML-guided simulations lead us to discover that the large optimal electromechanical responses can be achieved in CGFEs with average composition near the morphotropic phase boundary yet large compositional gradient. These CGFEs accommodate a coexistence of tetragonal, orthorhombic, and cubic phases in their domain structures, which flatten the energy barrier landscape and facilitate the rotation of polarization under mechanical field. Our proposed highly efficient design strategy can be readily adapted to identify CGFEs possessing other principal elements and properties, which will accelerate the discovery of new high-performance CGFE materials.

The exchange of electrical charges between a chemical reaction center and an external electrical circuit is critical for many advanced technological applications. From this perspective, "wiring” of polyoxometalates (POM) which is highly redox-active molecular metal oxide anions to conductive polymers (CPs) will be of great importance. Herein, POM-CP-based organic-inorganic hybrid composite film has been prepared electrochemically from mixtures of Keggin-type POM clusters (K7-xNaxPW11O39∙14H2O) and a triazine cored carbazole derivative. Incorporating POM clusters into cross-linked CPs has led to hybrid material with not only value-adding properties but also synergistic effects. When optical and electrical properties of the composite films prepared from different feed ratios have been examined, it has been observed that the incorporation of POM clusters into the conductive polymer structure has led to a decrease in the onset potential, response time, and bandgap as well as an increase in the optical contrast, stability, and charge capacity of the CPs.

This work describes the preparation and chemical modification of the graphene oxide platform with octa(aminopropyl)silsesquioxane, with subsequent deposition of Prussian Blue nanoparticles on its surface. The materials were characterized by Raman Spectroscopy, X-Ray Excited Photoelectron Spectroscopy and Transmission Electron Microscopy, which ensured the success of the proposed synthesis. The Differential Pulse Voltammetry technique was employed in order to apply the conventional electrode as a sensor for the detection of Diuron, a widely used pesticide due to its efficiency in controlling a wide range of weeds and grasses, but which has carcinogenic and genotoxic effects. The graphite paste electrode modified with the metallic complex was electroactive in the electrocatalytic detection of Diuron, with a detection limit of 4.96 nmol·L−1. Given this, it can be proposed that the material prepared in this work is included in the list of potential candidates for the development of electrochemical sensors for the detection of Diuron.

Metal oxide and carbon nanotube-based materials are widely preferred in supercapacitor and electrochemical sensor applications due to their interesting physicochemical structure. In this paper, we report the synthesis, characterization, and utilization of NiCeO2@f-MWCNT/EDA nanoparticles as electrode materials for supercapacitor applications. The characterization studies of NiCeO2@f-MWCNT/EDA nanomaterials were performed using X-ray diffraction (XRD), Transmission electron microscope (TEM), and Raman spectroscopy apparatus. The characterization methods revealed a good distribution of NiCeO2 on f-MWCNT/EDA and formed a new structure of NiCeO2@f-MWCNT/EDA nanoparticles. Electrochemical studies of NiCeO2@f-MWCNT/EDA nanoparticles showed a significant specific capacitance of between 2385 and 603 Fg−1 with good cyclic stability of 1000 cycles with capacity retention between 42% and 1.4% at 10 mV/s scan rate. The obtained results reveal that the prepared NiCeO2@f-MWCNT/EDA nanoparticles are promising electrode materials for supercapacitor devices.

Hydrogen peroxide (H2O2) is a significant constituent of several biological and industrial processes; however, as it is malignant to human health, the ability to detect its presence is indispensable. From the various H2O2 detection methods, enzyme-free electrochemical detection method is thriving in research, as it is economical, easy-to-use, stable, and provides repeatable platforms. Herein, we report on a metal-free, novel, biopolymer-based low-cost, stable, and easy-to-operate, conducting nanohybrid composite for the non-enzymatic detection of H2O2. This nanohybrid composite consists of a novel crosslinked chitosan (CS) and polyaniline (PANI) grafted graphene oxide (GO) (GOP) composite. In the first step, a gamma-irradiated GO (γGO) substrate is used for the in-situ graft polymerization of aniline, and following the grafted nanohybrid was incorporated in a CS matrix and crosslinked with tetraethylorthosilicate (TEOS) to form CS and GO composites. The sensor, fabricated by coating the newly prepared composite on a glassy carbon electrode, was tested for hydrogen peroxide detection in an alkaline solution, showing a low detection limit of 17.3 μM, a linear range up to 200 μM, and a sensitivity of 0.77 μA μM−1 cm−2. These notable results and comparable performance with the literature suggest that the electrochemical biosensor exhibit promising potential for a wide range of H2O2 detection.

In this study, CaCu3Ti4O12 (CCTO) ceramics with minor addition of SrO were fabricated by using a sol-gel method, aiming to simultaneously improve the breakdown field strength (Eb) and reduce the dielectric loss (tanδ). The addition of SrO induced precipitation of CuO and (Ca, Sr)TiO3 secondary phases in the grain boundaries, which improved the grain resistance and the grain boundary resistance (Rgb) by increasing the grain boundary density. Moreover, the CCTO ceramics with 6 mol% SrO addition exhibited a high Eb of 37.1 kV/cm and a low tanδ of 0.035 while maintaining a high dielectric constant of 2469. The enhancement in Eb was attributed to the improvement in Rgb, while the reduction in tanδ was associated with the increase in Rgb and the increase in the grain boundary activation energy. This study provides a new approach for the design of high-performance CCTO-based ceramics via the minor addition of SrO.

We investigated the effect of hafnium (Hf4+) substitution on the structural, morphology, electrical, and optical properties of barium titanate (BT), prepared via the modified (low-temperature sintered) solid-state reaction route. The structural refinement confirmed the formation of a single phase for pure and a mixture of phases for Hf-doped BT. The presence of [TiO6] and [HfO6] octahedra was confirmed by Raman analysis. The XPS analysis confirmed the formation of structural disordering associated with oxygen vacancies. The highest piezoelectric charge coefficient of 193 pC/N was found for BHT-5 (5% Hf). An energy storage efficiency ≥ 65% makes all the ceramics suitable for high-energy-density capacitors applications. With an increase in Hf4+ content, the optical bandgap widened. The direct optical bandgap ranged from 2.783 to 2.892 eV, making them ideal for optoelectronic applications. The presence of Ti3+/Hf3+ ions decreased the optical bandgap for all compositions.

Functional hybrid materials with unique electron transport path could be fabricated by the construction of heterojunction semiconductors with matched energy band structures, which exhibit excellent photocatalytic capacity in environmental treatment and new energy exploitation. Herein, ternary photocatalysts with Z-scheme heteojunctions were fabricated by Bi2S3-MoS2 deposition on TiO2 nanotube arrays (TiO2 NTs/Bi2S3-MoS2) via a solvothermal method. The design included the advantages of one-dimensional TiO2 nanotubes and high visible light responsive Bi2S3-MoS2 sensitizers, enhancing the solar harvesting, electron transfer and photocatalytic performance. The TiO2 NTs/Bi2S3-MoS2 exhibited outstanding photocatalytic pollutant removal and H2 evolution, and it also showed high visible light-driven photoelectric conversion. Additionally, the photocatalytic mechanism and active species for pollutant degradation were also revealed. In particular, the photocatalyst displayed remarkably high photocatalytic stability after sustained experimental cycles. It is anticipated that the Z-scheme heterogeneous photocatalyst would exhibit glorious achievement in practical applications.

In this study, the pristine PVDF and x% Ru/TiO2/PVDF (x = 0. 5, 1 & 1. 5 wt.%) photocatalytic composite membranes were cast by the phase inversion method. The prepared photocatalysts and photocatalytic membranes were characterized by various analytical techniques. All the prepared photocatalysts and photocatalytic membranes were evaluated for their photocatalytic activities towards the degradation of two significant hazardous textile dyes, namely methylene blue and crystal violet under visible light illumination. The% decolorization values of MB and CV dyes over 1% Ru/TiO2 photocatalyst & 1% Ru/TiO2/PVDF photocatalytic composite membrane were found to be 99% & 97% and 84% & 83% respectively under visible light irradiation. The photocatalytic decolorization followed the pseudo-first-order reaction, according to the kinetics investigations. The mineralization of MB and CV dyes was determined by TOC analysis and found to be 64% & 61% respectively. The recyclability of 1% Ru/TiO2/PVDF photocatalytic composite membrane test revealed high stability.