Efficient Heterostructure Research Articles

ZnS/MoS2 heterostructures on MXene: A strategy for improved polysulfide adsorption and conversion in Li-S batteries

The shuttle effect of polysulfides (LiPSs) and the sluggish sulfur redox kinetics are critical challenges hindering the practical application of lithium-sulfur (Li-S) batteries. This paper introduces ZnS/MoS2 heterostructures uniformly anchored on MXene (ZnS/MoS2@MXene) for use in Li-S batteries via a modified separator. The heterogeneous interface of ZnS/MoS2@MXene facilitates efficient adsorption, catalysis, and conversion of LiPSs, thereby suppressing the shuttle effect and significantly enhancing sulfur redox kinetics. The redox kinetics and the mechanism behind the enhanced chemisorption effect of ZnS/MoS2@MXene are thoroughly investigated using density functional theory (DFT) calculations. As anticipated, Li-S batteries employing ZnS/MoS2@MXene demonstrate remarkable rate performance and long-term cycling stability. The specific capacity of the ZnS/MoS2@MXene battery reaches 1504.4 mAh g−1 at 0.1C. The ZnS/MoS2@MXene battery retains a high discharge specific capacity of 741 mAh g−1 after 500 cycles at 1C, with a per-cycle decay rate of just 0.067 %. Notably, with a sulfur loading of 5.6 mg cm−2, the areal specific capacity remains at 3.6 mAh cm−2 after 100 cycles at 0.2C. This study presents a viable strategy for developing more efficient heterostructure catalysts for Li-S batteries.

Enhanced Adsorption Kinetics and Capacity of a Stable CeF3@Ni3N Heterostructure for Methanol Electro‐Reforming Coupled with Hydrogen Production

Alkaline methanol‐water electrolysis system is regarded as an appealing strategy for electro‐reforming methanol into formate and producing hydrogen with low energy‐consumption compared with alkaline water electrolysis. However, stability and selectivity under high current densities for practical application remain challenging. Herein, a CeF3@Ni3N nanosheets array anchored on carbon cloth (CeF3@Ni3N/CC) was fabricated. The gradual extrusion of F species from Ni(OH)2 lattices can stabilize hierarchical structure and construct abundant heterostructure interfaces. Moreover, CeF3 can modulate electron distribution of Ni3N, thus simultaneously enhancing the surface adsorption kinetics and capability of methanol and OH‐, which is conducive to enhanced methanol oxidation reaction (MOR) activity and selectivity. Therefore, bifunctional CeF3@Ni3N/CC exhibits low potential of 1.43 V at 500 mA cm‐2, along with high stability over 72 h and high faradaic efficiency (FEs) in MOR, as well as an overpotential of 76 mV to achieve 50 mA cm‐2 for hydrogen evolution reaction (HER). Furthermore, membrane‐free CeF3@Ni3N/CC||CeF3@Ni3N/CC cell for MOR||HER delivers high electrocatalytic activity, long‐term stability and FEs at high current density of 300 mA cm‐2. This study highlights the importance of optimizing surface adsorption behavior of active species, as well as rational design of highly efficient heterostructure electrocatalysts for methanol upgrading coupled with hydrogen production.

Enhanced Adsorption Kinetics and Capacity of a Stable CeF3@Ni3N Heterostructure for Methanol Electro-Reforming Coupled with Hydrogen Production.

Alkaline methanol-water electrolysis system is regarded as an appealing strategy for electro-reforming methanol into formate and producing hydrogen with low energy-consumption compared with alkaline water electrolysis. However, stability and selectivity under high current densities for practical application remain challenging. Herein, a CeF3@Ni3N nanosheets array anchored on carbon cloth (CeF3@Ni3N/CC) was fabricated. The gradual extrusion of F species from Ni(OH)2 lattices can stabilize hierarchical structure and construct abundant heterostructure interfaces. Moreover, CeF3 can modulate electron distribution of Ni3N, thus simultaneously enhancing the surface adsorption kinetics and capability of methanol and OH-, which is conducive to enhanced methanol oxidation reaction (MOR) activity and selectivity. Therefore, bifunctional CeF3@Ni3N/CC exhibits low potential of 1.43 V at 500 mA cm-2, along with high stability over 72 h and high faradaic efficiency (FEs) in MOR, as well as an overpotential of 76 mV to achieve 50 mA cm-2 for hydrogen evolution reaction (HER). Furthermore, membrane-free CeF3@Ni3N/CC||CeF3@Ni3N/CC cell for MOR||HER delivers high electrocatalytic activity, long-term stability and FEs at high current density of 300 mA cm-2. This study highlights the importance of optimizing surface adsorption behavior of active species, as well as rational design of highly efficient heterostructure electrocatalysts for methanol upgrading coupled with hydrogen production.

A strongly coupled 1T'-ReSe2@2H-MoSe2 van der Waals heterostructure for efficient electrocatalytic hydrogen evolution at high current densities.

Developing efficient and durable non-noble metal electrocatalysts for high current-density hydrogen evolution reactions (HER) is a pressing requirement for commercial industrial electrolyzers. In this study, a vertical 1T'-ReSe2@2H-MoSe2 van der Waals heterostructure was developed through interface engineering to enhance the advantages of each component and expose numerous active sites. Experimental investigations and density functional theorycalculations demonstrate significant electronic coupling at the interface between 1T'-ReSe2 and 2H-MoSe2, with suitable Gibbs free energy for hydrogen adsorption. The 1T'-ReSe2@2H-MoSe2 heterostructure catalyst achieves high current density HER with low overpotentials of 191 mV to generate up to 800 mA/cm2 in 0.5 M H2SO4, outperforming commercial 5% Pt/C catalysts. Moreover, this catalyst exhibits rapid reaction kinetics and long-term durability, illustrating a successful approach to designing efficient heterostructure electrocatalysts for hydrogen production through interface engineering.

Constructing 2D PtSe2/PtCo Heterojunctions by Partial Selenization for Enhanced Hydrogen Evolution

AbstractThe rational design and fabrication of 2D heterojuctions are proven a promising strategy for boosting the performance of electrocatalysts. Although 2D platinum diselenide (PtSe2) exhibits catalytic activity for hydrogen evolution reaction (HER), the catalytic performance is still unsatisfactory due to its inert basal plane, wide bandgap, and poor electron transfer ability. Herein, a new strategy is reported to construct PtSe2/PtCo heterojunctions by partial selenization of PtCo alloy for high‐efficiency HER electrocatalyst, which exhibits a low overpotential of 38 mV at the current density of 10 mA cm−2, a small Tafel slope of 22 mV dec−1, and a superior stability over 24 h and 1000 cycles. The outstanding HER activity of the catalyst arises from the strong electronic interactions between PtSe2 and PtCo in the heterojunctions, which induce electron transferring from PtSe2 to PtCo and the d‐band center down shifting, and thus optimize the H* adsorption/desorption. This work provides a novel strategy for constructing highly efficient heterostructure electrocatalysts, which facilitates the applications of hydrogen energy conversion.

Rapid synthesis of novel S-scheme CaBi6O10/Bi2WO6 heterojunction film for efficient p-chlorophenol photocatalytic degradation

Efficient photocatalysts played a crucial role for degrading phenol pollutants in wastewater and vital for environmental remediation. In this study, a series of novel CaBi6O10/Bi2WO6 (CBO/BWO) step-scheme (S-scheme) heterojunction films were synthesized on the glass substrates through a facile and rapid spraying-calcination method. The CBO/BWO film demonstrated superior visible-light-driven catalytic activity for p-chlorophenol (4-CP) degradation within the fixed-bed photoreactor setup, compared with those of the single-component samples. Typically, the optimal 40CBO/BWO catalyst achieved 4-CP degradation efficiency of approximately 89.5 % after only 60 min under light exposure, attributed to the enhanced visible-light-absorption property and effective charge separation within the S-scheme heterojunction while maintaining high redox abilities among photoinduced carriers. Furthermore, the CBO/BWO catalyst displayed robust resistance to various metal cationic additives. Multiple key intermediates, such as phenol, dihydroxybenzene, benzoquinone and maleic acid, were identified in catalyzing process of 4-CP decomposition via oxidation processes involving hydroxyl radicals and superoxide radical as the primary active species. The above feasible photodegradation mechanism was elucidated and proven. Hence, this work offers valuable insights into developing efficient heterostructure photocatalysts for practical application of environmental remediation.

Synthesis of magnetic NiFe2O4/rGO heterostructure as potential photocatalyst for a breakdown of malachite green (MG) dye under the visible source of light

The development of reactive radical generators, visible-light active photocatalysts with predictable stability, and efficient activity toward the breakdown of organic pollutant continue to be the primary goals of research in the area of photocatalytic environmental restoration. The present concern to on the development of an efficient heterostructure with a band gap operated on a visible region. The rGO incorporation into spinel material also decreases the agglomeration and provides a large surface area. The efficacy of NiFe2O4 (NF) nanoparticles, which are supported by rGO, as a photocatalyst for the breakdown of malachite green (MG) dye. The incorporation of rGO into NFO was investigated with the band gap property of the fabricated material using Tauc's plot profile. The NF/rGO nanocomposite underwent a reduction in magnetic properties determined through Vibrating Sample Magnetometer (VSM) analysis. However, the coercivity of the nanocomposite experienced a significant increase. When subjected to visible light, the degradation rate of malachite green (MG) dyes with NF/rGO was comparatively faster (93.84 %) than that of NF (64.33 %) and rGO (79.41 %). The cyclic photocatalytic degradation process exhibited notable reusability and stability of the magnetic recycling nanocomposite. The photocatalytic results revealed that the developed nanocomposite acts as a potential photocatalyst and it can also be employed in different applications.

Theoretical Prediction Leads to Synthesize GDY Supported InOx Quantum Dots for CO2 Reduction

AbstractThe preparation of formic acid by direct reduction of carbon dioxide is an important basis for the future chemical industry and is of great significance. Due to the serious shortage of highly active and selective electrocatalysts leading to the development of direct reduction of carbon dioxide is limited. Herein the target catalysts with high CO2RR activity and selectivity were identified by integrating DFT calculations and high‐throughput screening and by using graphdiyne (GDY) supported metal oxides quantum dots (QDs) as the ideal model. It is theoretically predicted that GDY supported indium oxide QDs (i.e., InOx/GDY) is a new heterostructure electrocatalyst candidate with optimal CO2RR performance. The interfacial electronic strong interactions effectively regulate the surface charge distribution of QDs and affect the adsorption/desorption behavior of HCOO* intermediate during CO2RR to achieve highly efficient CO2 conversion. Based on the predicted composition and structure, we synthesized the advanced catalytic system, and demonstrates superior CO2‐to‐HCOOH conversion performance. The study presents an effective strategy for rational design of highly efficient heterostructure electrocatalysts to promote green chemical production.

Unravelling the effect of Ti3+/Ti4+ active sites dynamic on reaction pathways in direct gas-solid-phase CO2 photoreduction

Converting CO2 to CH4 by solar-powered catalysis involves complex steps that produce a range of by-products. Therefore, designing efficient heterostructures for a particular chemical synthesis is challenging. The optimisation of photocatalyst surfaces can achieve the desired CO2 photoreduction pathway. Herein, we developed TiO2/CdSe nanocrystals with both amorphous and crystalline TiO2 surfaces. In situ EXAFS analysis revealed that the amorphous surface contains abundant active Ti3+ sites, while the crystalline surface is limited. Moreover, the amorphous surface of TiO2/CdSe exhibits self-regenerating Ti3+ active sites, which enable a novel CH4 cycle. Density functional theory calculation showed that an amorphous structure enhances electron transfer and localisation to Ti3+, favouring CO2 adsorption. In situ DRIFTS analysis showed different CO2 to CH4 pathways on both surfaces. These results show the potential for enhanced photocatalytic CO2 reduction through surface engineering, which has far-reaching implications for sustainable energy conversion.

Vanadium-modulated hierarchical Ni2P/Ni12P5 as an efficient heterostructure electrocatalyst for large-current-density hydrogen evolution

Seawater splitting in alkaline media emerges an ideal alternative to conventional freshwater electrolysis by fully utilizing natural resources for sustainable and scalable production of green hydrogen. Exploiting the efficient and robust seawater electrocatalyst towards large-current-density hydrogen production is urgently rewarding, but challenges remain. Herein, a free-standing hierarchical vanadium-doped Ni2P/Ni12P5 heterostructure nanoflower array grown in-situ on nickel foam (V-Ni2P/Ni12P5/NF) is successfully fabricated via calcination protocol by phosphorization of the NiV-LDH precursor in Ar/H2 protective atmosphere. Profiting from the unique hierarchical structure, enhanced electrical conductivity and optimized electronic configuration, the integrated V-Ni2P/Ni12P5/NF heterogeneous electrocatalyst presents highly active and stably electrocatalytic performance for hydrogen evolution. As expected, the as-obtained V-Ni2P/Ni12P5/NF delivers overpotentials of 211/215 mV, 293/306 mV and 334/355 mV in alkaline/alkaline simulated seawater media at high current densities of 100, 500 and 1000 mA/cm2 respectively, accompanying with a remarkable catalytic durability for at least 40 h of consecutive electrolysis in both conditions. This work provides a new insight to construct highly efficient electrocatalysts for alkaline water/seawater towards large-scale hydrogen evolution.

G-C3N4@CPP/BiOClBr-OV biomimetic fractal heterojunction synergistically enhance carrier dynamics for boosted CO2 photoreduction activity

In recent years, there has been significant interest in generating high-value solar fuels via the photocatalytic reduction of CO2. Nonetheless, its large-scale application is impeded by low energy utilization efficiency and limited photocatalytic activity. This study employed carbonized pomelo peel (CPP), a waste biomass material, to successfully craft a CN@CPP/BOCB-OV ternary heterojunction abundant in N/O vacancy defects through secondary calcination and in-situ growth. The construction of the heterojunction and the emergence of defect-induced donor energy levels create a built-in interface electric field (IEF) and an interfacial electron transmission channel respectively, fortifying the separation and transport of photogenerated electrons. Crucially, following the incorporation of CPP, its distinctive 3D porous and heterojunction bionic flower structures expand the spectral absorption range. Acting as a superior electron acceptor, CPP reinforces the IEF, notably boosting carrier transport efficiency. Simultaneously, it operates as a hub for photothermal synergy and CO2 adsorption activation, achieving multi-site synergistic enhancement of photoreduction CO2 activity. Hence, the CN@CPP/BOCB-OV heterojunction demonstrates a substantial quantitative enhancement in CO2 photoreduction activity. Remarkably, it exhibits the capability to catalyze CO2 reduction even under infrared light excitation, which is of great significance for the cascade utilization of solar energy. Furthermore, employing DFT calculations, we elucidate the electron transfer mechanism at the heterojunction interface and outline potential pathways for photocatalytic CO2 reduction. The combination of waste biomass utilization, heterostructure construction and defect engineering provides a promising strategy for developing efficient heterostructure photocatalysts.

A 3D hierarchical TiO2/CaIn2S4/C3N4 arrays photoanode with dual-heterojunction for enhanced photoelectrochemical performance

A novel 3D hierarchical TiO2/CaIn2S4/C3N4 arrays with dual heterojunctions photoanode is constructed by stepwise deposition of CaIn2S4 nanosheets and ultrathin C3N4 onto the well-aligned TiO2 nanorods arrays. Integrating the merit of the superior ability of CaIn2S4 and C3N4 to harvest visible light, dual type-Ⅱ heterojunction band structure and one-dimensional ordered nanostructures, the TiO2/CaIn2S4/C3N4 photoanode exhibits simultaneous significant improvements in visible-light harvesting, charge separation and electron transfer capability. At 1.23 V (versus reversible hydrogen electrode) under AM 1.5 G irradiation, the TiO2/CaIn2S475/C3N4 photoanode exhibits a photocurrent density of 4.5 mA cm−2, which is 5.2 and 51.1-fold higher than that of TiO2/CaIn2S475 and pristine TiO2 photoanode, respectively. Moreover, the applied bias photo-to-current efficiency (ABPE) of the TiO2/CaIn2S475/C3N4 photoanode reaches 3.5% at 0.36 V (versus reversible hydrogen electrode). These results are helpful for fabricating more efficient heterostructure photoelectrodes.

Tuning the Activity and Stability of CoCr-LDH by Forming a Heterostructure on Surface-Oxidized Nickel Foam for Enhanced Water-Splitting Performance.

The development of low-cost, efficient catalysts for electrocatalytic water splitting to generate green hydrogen is a hot topic among researchers. Herein, we have developed a highly efficient heterostructure of CoCr-LDH on NiO on nickel foam (NF) for the first time. The preparation strategy follows the simple annealing of a cleaned NF without using any Ni salt precursor, followed by the growth of CoCr-LDH nanosheets over the surface-oxidized NF. The CoCr-LDH/NiO/NF catalyst shows excellent electrocatalytic activity and stability toward oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in a 1 M KOH solution. For OER, only 253 mV and for HER, only 185 mV overpotentials are required to attain a 50 mA cm-2 current density. Also, the long-term stability of both the OER and HER for 60 h proves its robustness. The turnover frequency value for the OER increased 1.85 times after the heterostructure formation compared to bare CoCr-LDH. The calculated Faradaic efficiency values of 97.4 and 94.75% for the OER and HER revealed the high intrinsic activity of the heterostructure. Moreover, the heterostructure only needs 1.57 V of cell voltage when acting as both the anode and the cathode to achieve a 10 mA cm-2 current density. The long-term stability of 60 h for the total water-splitting process proves its excellent performance. Several systematic pre- and post-experiment characterizations prove its durable nature. These excellent OER and HER activities and stabilities are attributed to the surface-modified electronic structure and thin nanosheet-like surface morphology of the heterostructure. The thin, wide, and modified surface of the catalyst facilitates the diffusion of ions (reactants) and gas molecules (products) at the electrode/electrolyte interface. Furthermore, electron transfer from n-type CoCr-LDH to p-type NiO results in enhanced electronic conductivity. This study demonstates the effective design of a self-supported heterostructure with minimal synthetic steps to generate a bifunctional electrocatalyst for water splitting, contributing to the greater cause of green hydrogen economy.

Insight into the synergistic effect of defect and strong interface coupling on ZnIn2S4/CoIn2S4 heterostructure for boosting photocatalytic H2 evolution

Steering the directional carrier migration across the interface is a central mission for efficient photocatalytic reactions. In this work, an atomic-shared heterointerface is constructed between the defect-rich ZnIn2S4 (HVs-ZIS) and CoIn2S4 (CIS) via a defect-guided heteroepitaxial growth strategy. The strong interface coupling induces adequate carriers exchanging passageway between HVs-ZIS and CIS, enhancing the internal electric field (IEF) in the ZnIn2S4/CoIn2S4 (HVs-ZIS/CIS) heterostructure. The defect structure in HVs-ZIS induces an additional defect level, improving the separation efficiency of photocarriers. Moreover, promoted by the IEF and intimate heterointerface, photogenerated electrons trapped by the defect level can migrate to the valence band of CIS, contributing to massive photogenerated electrons with intense reducibility in HVs-ZIS/CIS. Consequently, the HVs-ZIS/CIS heterostructure performs a boosted H2 evolution activity of 33.65 mmol g−1 h−1. This work highlights the synergistic effects of defect and strong interface coupling in regulating carrier transfer and paves a brave avenue for constructing efficient heterostructure photocatalysts.

Synthesis, Characterization of Dy2NdSbO7/Bi2WO6 Heterojunction Photocatalyst and the Application for the Photocatalytic Degradation of Chlorpyrifos under Visible Light Irradiation

A groundbreaking photocatalytic nanomaterial, Dy2NdSbO7, was fabricated smoothly using the hydrothermal synthesis technique for the first time. Apart from that, Dy2NdSbO7/Bi2WO6 heterojunction photocatalyst (DBHP) was initially fabricated using the solvothermal fabrication technique. X-ray diffractometer, Fourier-transform infrared spectrometer, Raman spectrometer, UV-visible spectrophotometer, X-ray photoelectron spectrometer, inductively coupled plasma optical emission spectrometer, transmission electron microscope, and X-ray energy dispersive spectroscopy have been applied to evaluate and investigate the thetastructure, morphology, and physicochemical properties of synthesized samples. The results confirmed that the pyrochlore-type crystal structures of Dy2NdSbO7 belonged to the Fd3m space group with the cubic crystal system and the β-pyrochlore-type crystal structures of Bi2WO6 which belonged to the Pca21 space group with orthorhombic crystal system. Under visible light exposure for 155 min (VLP-155min) using DBHP in the capacity of the photocatalytic nanomaterial, the removal efficiency of chlorpyrifos (CPS) saturation reached 100%. Comparison of CPS removal efficiency after VLP-155min revealed that DBHP exhibited higher removal efficiency than Dy2NdSbO7, Bi2WO6, or N-doped TiO2 photocatalyst, with removal efficiency 1.15 times, 1.23 times, or 2.55 times higher, respectively. Furthermore, the oxidizing capability of free radicals was investigated using trapping agents. Results demonstrated that superoxide anions exhibited the strongest oxidative capability, followed by hydroxyl radicals and holes. The results presented in this study lay a robust groundwork for future investigations and advancements in the field of highly efficient heterostructure material. These findings have significant implications for the development of environmental remediation strategies and provide valuable insights into sustainable solutions for addressing CPS contamination.

An efficient heterostructure MoP2-CoMoP-NC electrocatalyst derived from ZIF-67 for hydrogen evolution reaction

The fabrication of heterostructure electrocatalysts is an effective method for optimizing catalytic activity and improving electrocatalytic performance. Herein, we designed a novel MoP2-CoMoP-NC heterostructure electrocatalyst derived from ZIF-67. The prepared MoP2-CoMoP-NC displays wheat-spike nanorods cross-linked with each other for providing a large electrochemically active surface area. Furthermore, the nitrogen-doped carbon framework derived from ZIF-67 successfully wrapped nanoparticles, which is advantageous for enhancing the stability and conductivity of the catalyst. The heterointerface between MoP2 and CoMoP facilitates mass transport and charge transfer. The MoP2-CoMoP-NC/NF heterostructure electrocatalyst shows enhanced electrocatalytic activity, with a relatively low overpotential of 88.2 mV at 10 mA cm−2 for the hydrogen evolution in alkaline conditions and a Tafel slope of only 65.9 mV dec−1. Furthermore, long-term measurements showed that MoP2-CoMoP-NC/NF has superior durability in alkaline solutions.

NiS–NiS2 heterostructure for efficient electrocatalytic overall urea splitting

Heterogeneous catalysts possess many advantages over single-phase catalysts. However, how to tune the heterogeneous interface state and density in heterostructures to optimize their electrocatalytic performance is still a challenge. Here, we propose a method for the preparation of NiS–NiS2 heterostructure by vulcanization of nickel foam at high temperature, which can effectively tune the weight ratio of NiS to NiS2 in heterostructure and their corresponding electrocatalytic urea oxidation reaction (UOR), hydrogen evolution reaction (HER) and overall urea splitting performance. The electrocatalytic activity show a trend of volcano curve with the increase of the ratio of NiS to NiS2, and the best electrocatalytic activity was obtained at the ratio of 6.74, in which the potentials at current density of 10 mA cm−2 of UOR, HER and overall urea splitting are 1.28 V, −49.5 mV and 1.34 V versus reversible hydrogen electrode (vs. RHE), and the Tafel slopes are 21.7, 74.1 and 90.9 mV dec−1, respectively. Furthermore, it also demonstrates excellent electrocatalytic stability. This work provides an effective way to tune the interfacial structure of heterogeneous electrocatalysts while significantly improving their electrocatalytic performance, which is beneficial to the development of efficient heterostructure and expand their applications.

Modeling and formation of a single-walled carbon nanotube (SWCNT) based heterostructure for efficient solar energy: Performance and defect analysis by numerical simulation

This work introduces a new highly efficient heterostructure solar cell that shows the supremacy of the single-walled carbon nanotube as an absorber layer and platinum (Pt) as a back contact. This article focuses on the most important process: optimizing the thickness and acceptor concentration of the absorber layer. Another novel fact in this work is that minorities have been included as a replica of defects and the Auger hole/electron capture coefficient, and the variations in defects have been shown with some flawless contour plots. As the whole study has been carried out using a simulator, it might not be completely realistic, but it shows outcomes close to reality. In addition, the use of minorities takes this simulation work closer to the physical one. A contemporary model—Al/ZnO/TiO2/SWCNT/SnS/Pt—has been investigated in this work for efficient performance. At the end of tuning, the input parameters are set at thickness (W) = 1.5 µm, acceptor concentration (NA) = 1 × 1020 cm−3, and defects = 1 × 1015 cm−3. Under these optimum conditions, this model has shown outstanding outcomes: VOC = 1.04 V, JSC = 41.91 mA cm−2, FF = 72.12%, and η = 31.57%. Although an efficiency of 32.86% was achieved at NA = 1 × 1021 cm−3, it is difficult to keep the acceptor concentration high in reality. Hence, the optimum value of the acceptor concentration is considered at 1 × 1020 cm−3.

Design of a highly efficient heterostructure of transition metal tellurides with outstanding photocatalytic and antimicrobial potential

This work aimed to synthesize an effective material having greater potential to reduce water pollution caused by industrial waste and exhibit efficient antibacterial potential. The transition metals (Manganese-Mn, Zinc-Zn) and post transition metal (Tin-Sn) reacted with TeO2 in a stoichiometric ratio by adopting a solid-state reaction. The crystallite size of the synthesized compounds MnTeO3 (D1), ZnTeO3 (D2), and SnTe3O8 (D3) was measured by the Debye-Scherrer formula by extracting data from the FWHM. D1 and D2 exhibit the orthorhombic structure whereas D3 has a simple cubic structure and crystalline size was measured by FWHM i.e., 221 nm, 458 nm, and 153 nm. Catalytic degradation efficiency for the removal of MB dye was found to be in the range of 66%-73%. Additionally, these substances have strong antimicrobial action alongside both bacteria and fungi, such as Escherichia coli, Staphylococcus aureus with maximal zone inhibitions of 35.0 mm and 12.5 mm for each kind of bacterium. The highest antifungal activity of Mn integrated was estimated to be 37.2 mm versus Aspergillus niger and 15.1 mm alongside Coccidioides. According to the findings, the manufactured material has effective photocatalytic and antimicrobial activities.

Metal-organic gel derived ZnO/α-Fe2O3 heterostructures for sensitive NO2 detection

Fabrication of metal oxide semiconductor heterostructures is an important means to improve sensor performance. However, the design of efficient heterostructures to reduce the operating temperature of metal oxides and obtain high sensitivity and selectivity remains a challenge. In this work, ZnO/α-Fe2O3 heterostructures were prepared by pyrolysis of Fe-based organic gel on ZnO nanorods, and their NO2 sensing properties were systematically studied. The α-Fe2O3 nanoparticles transformed from Fe-organic gel are evenly dispersed on the surface of ZnO nanorods, endowing the materials with a large specific surface area and remarkable charge modulation at the ZnO/α-Fe2O3 interface. The ZnO/α-Fe2O3 sensor shows superior selectivity and repeatability for NO2 detection at 175 °C, as well as short response-recovery time (24/32 s), low detection limit (79 ppb) and reliable stability. This study provides a useful strategy for the construction of core-shell heterostructure sensing materials.