Doped Oxide Research Articles

Wide Bandgap Donor can Offer High‐Efficiency LED Indoor Organic Photovoltaic with Indium‐Doped Zinc Oxide Electron Transport Layer

Indoor organic photovoltaic (OPV) cells offer a compelling solution for powering diverse electronic devices integrated into the Internet of Things (IoT) network. They are prized for their robust power conversion efficiency (PCE), mechanical resilience, and ultra‐thin nature. The recent surge in inverted‐structure OPVs reflects their enhanced stability over conventional designs. Despite the advantage, their adaptation for indoor light utilization remains underexplored. Optimal selection of an electron transport layer (ETL) with precise energy band alignment is critical in this system. Herein, an inverted‐structured OPV is fabricated utilizing PBDB‐T as the wide bandgap donor, with a focus on enhancing its PCE under 1000 lx LED illumination through the doping of the zinc oxide‐ (ZnO‐) based ETL with indium (In). The results indicate that the device utilizing undoped ZnO as the ETL achieves a peak PCE of 9.42% under these specified conditions. Conversely, the OPV utilizing In‐doped ZnO as the ETL achieves a significantly higher PCE of 29.78% with 5 at% In, indicates the usefulness of ETL doping by In. This may be caused by the tuning of energy band alignment, improvement in electron mobility, and reduction in surface roughness of ZnO by In doping.

Role of Cerium-Layered Double Hydroxide-Derived Oxide Dopants in Vanadium Phosphorus Oxide for Selective Oxidation of n-Butane

Role of Cerium-Layered Double Hydroxide-Derived Oxide Dopants in Vanadium Phosphorus Oxide for Selective Oxidation of <i>n</i>-Butane

Mechanism of Sulfate Radical Formation on Activation of Persulfate Using Doped Metal Oxide and Its Role in Degradation of Tartrazine Dye in an Aqueous Solution.

Degradation of tartrazine dye (TZD) was performed in this study using sulfate radicals (SO4•-) generated from the activated sodium persulfate (SPS) using Fe3O4@PDA nanoparticles (NPs). The NPs were characterized by Fourier transform infrared (FTIR), vibrating sample magnetometer (VSM), X-ray diffraction (XRD), high-resolution scanning electron microscopy (HR-SEM), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM), and energy-dispersive X-ray spectroscopy (EDX). The average particle size of the NPs was 17.49 nm from XRD analysis. The presence of the C-N group at 1129 cm-1 in FTIR and 2.54% of the nitrogen element identified from the EDX plot was evidence of successful doping of polydopamine (PDA). Superparamagnetic nature with a decrease in the Ms value to 42.015 emu/g after doping was determined. Doping was further confirmed by XPS analysis with binding energies at 399.68 and 400.99 eV. The average particle size from HRTEM analysis was 21.47 nm with a lattice spacing of 0.30 nm. Turnover number (TON) and turnover frequency (TOF) values for Fe3O4@PDA were determined to be 3.72 and 0.0248 min-1 with respect to different systems, respectively. Optimum conditions for the Fe3O4@PDA/SPS system were 50 ppm TZD, 0.9 g/L catalyst, 12 mM SPS, and pH 4 with 94.68% efficiency in 150 min. The inhibition effect of ions in TZD degradation followed the order humic acid <NO3- < Cl- < CO32. The kinetic model fitting the Fe3O4@PDA/SPS system has pseudo-second-order kinetics. Excess formation of SO4•- produced hydroxyl radicals (•OH) that were identified by a scavenging test. Reusability of the NPs was performed for five cycles and showed acceptable degradation performance up to 82.47%. The intermediates identified from gas chromatography-mass spectrometry (GCMS) proved the cleavage of azo and sulfonate groups of TZD with the formation of nontoxic intermediates. Finally, the phytotoxicity assessment was studied using Vigna radiata (Green grams). The % decrease of the root, shoot, and seedling length for the degraded dye solution was negligible. Hence, this study proved that the Fe3O4@PDA/SPS system could effectively degrade TZD with nontoxic intermediate formation.

On the Nature of HOPG-Supported Pt1Ti2O7 and its Decomposition of a Nerve Agent Simulant: A Cluster Model of a Single Atom Catalyst Active Site.

Chemical weapons, including hyper lethal nerve agents, are a persistently looming threat across the modern geopolitical landscape. There is a pressing need for the design and development of improved protective materials, which can be substantially aided by the cultivation of a fundamental molecular-level understanding of candidate systems and the corresponding decomposition chemistry. The emergence of the exciting new class of single atom catalyst (SAC) materials has enhanced the prospect of subnanoscale design tailoring in the hopes of optimizing activity and selectivity for a variety of chemical applications. Here, we apply our recently developed experimental technique for modeling the active sites of such SAC materials through the preparation of surface supported size-selected single metal-atom doped metal oxide clusters. The propensity for an SAC cluster model system for Pt1/TiO2 materials, Pt1Ti2O7 supported on highly oriented pyrolytic graphite (HOPG), to adsorb and decompose nerve agent simulant dimethyl methylphosphonate (DMMP) was investigated through a combination of temperature-programmed desorption/reaction (TPD/R) and X-ray photoelectron spectroscopy (XPS). XPS measurements of the as-prepared Pt1Ti2O7 clusters supported the successful isolation of single Pt atoms in clusters monodispersed across the HOPG surface. TPD/R experiments showed that the reactivity exhibited by the Pt1Ti2O7 clusters was distinct from that of Ti2O7 clusters lacking the single Pt atom. It was found that DMMP decomposed over Pt1Ti2O7 upon heating to as low as room temperature, and higher temperature treatments evolved exclusively H2O, CO, and H2, while decomposition over Ti2O7 evolved only methanol and formaldehyde at elevated temperatures. This indicated the promotion of C-H and PO-C bond cleavage within DMMP due to the presence of single Pt atoms in the clusters. Further, the Pt1Ti2O7 clusters were found to desorb P-containing decomposition species, preventing active site poisoning; however, a change of reactivity reflecting that of Ti2O7 was observed following a single TPD/R cycle. This suggested the encapsulation of active Pt sites by titanium oxide during high temperature treatment and is thus an issue deserving of serious attention in the study of Pt1/Ti2O7 SAC materials.

Charge separation by switching heterojunction system from Type-II to S-scheme for enhanced photocatalytic activity: Environmental detoxification and H2 production

The development of highly efficient photocatalysts is essential for harnessing solar energy for pollutant degradation and hydrogen (H2) production. This study provides a novel ternary S-scheme photocatalyst (Fe2O3/Bi2O3/g-C3N4), prepared from optimized binary 20-Bi-C via a simple electrostatic self-assembly method for the first time. Using various methods including UV–vis DRS, PL, ESR, photocurrent, Mott-Schottky, XPS, XRD, FTIR, SEM, TEM, and BET, the optical, structural, and morphological characteristics of the produced materials were fully studied. The photocatalytic performance of as-manufactured materials was evaluated through the degradation of the Ciprofloxacin (CIP) and H2 production. Under optimized conditions determined by the RSM method, a maximum CIP degradation of 97.20 % was achieved at a rate of 0.053 min−1, with the catalyst dosage: 0.44 g/l, CIP concentration: 26.07 mg/l, pH: 6.29 and Time: 63.01. The optimized heterojunction exhibited an exceptional photocatalytic H2 generation rate of 2428 μmol·g−1·h−1 within 2 h, surpassing the binary 20-Bi-C photocatalyst by 1.3 times. Furthermore, after five continuous cycles, the 5-Fe2O3/Bi-C photocatalyst showed good chemical stability and reusability, sustaining a degradation rate of over 96 % and a TOC removal of 80 %. Experiments on the identification of free radicals have demonstrated the important roles that O2−, h+, and OH species play in the photocatalytic process. The enhancement mechanism of 5-Fe2O3/Bi-C involves the successful synthesis of Fe2O3/Bi-C photocatalyst with well-aligned positions of band gap edges, enabling the facile charge transfer through S-Scheme mechanism. Furthermore, the study investigates the impact of environmental factors, including solution pH, water matrices, and the efficiency of the synthesized photocatalyst on other organic pollutants. The photocatalytic degradation behavior of CIP is predicted using LC-MS analysis. This work provides a new method for building S-scheme heterojunctions by creatively converting the type-II heterojunction system to an S-scheme by metal oxide doping.

Effects of Ni Loadings on the Structure and Morphology of Carbon Nanotubes Using Nickel Doped Iron Oxide Catalysts

AbstractIron oxide and their different doped iron oxide catalyst have been used for decades and are considered as efficient catalysts in several synthesis schemes including synthesis of carbon nanotubes. The iron oxide of the catalyst is abundant in nature, high catalytic activity at low over potentials, stability in basic media and low cost, making it environmentally and economically attractive. Nickel doped iron oxide catalyst have not been reported in the literature. Doping of nickel over iron oxide catalyst, different percentage 1 %, 5 %, 10 % and 20 % were done by impregnation method. The samples were characterized by X‐Ray powder Diffraction (XRD), Fourier‐Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Energy Dispersive X‐ray (EDX) and Thermo Gravimetric Analysis (TGA). Nickel doped iron oxide was used as catalyst for the synthesis of carbon nanotubes (CNTs) and doping changed the morphology of carbon nanotube (CNTs). FTIR results confirmed the doping and presence of different functional groups. Chemical vapor deposition (CVD) was carried out for the synthesis of multiwall carbon nanotubes (MWCNTs) on nickel doped iron oxide catalyst for different percentage (1 %, 5 %, 10 % and 20 %) separately. CVD assembly was carried in tube furnace and the reaction was checked at two different temperature i.e 700 °C and 750 °C and using methane and compressed natural gas (CNG) as precursors. The catalyst was activated in the furnace at 800 °C for an hour. Methane and argon were used in proportion 2 : 1 inside the furnace. SEM showed formation of CNTs at 750 °C with CNG precursor. Formation of CNTs increased with increasing doping with this CNTs was confirmed by SEM.

Advancement of Electro-Optical Properties through Changes in the Physicochemical Composition of Hybrid Thin Films by Doping Reduced Graphene Oxide into a Sol-Gel Process Solution.

A hybrid thin film was fabricated by doping graphene oxide into a sol-gel solution containing a mixture of zirconium, bismuth, and indium oxide. The thin film was fabricated using a brush coating process. The graphene oxide doping ratios used were 0, 5, and 15 wt%. During the thin film fabrication process, the produced sol-gel solution generates a contractile force due to the shear stress of the brush bristles, resulting in a microgroove structure. This structure was confirmed through scanning electron microscopy analysis, which revealed the clear presence of rGO. Comparing the electrical properties of a zirconium bismuth indium oxide thin film without graphene oxide doping and a thin film doped with 15 wt% graphene oxide, the electro-optical properties were significantly improved with graphene oxide doping. In general, the threshold voltage decreased by approximately 0.42 V. In addition, bandgap measurements confirmed the improved conductivity characteristics with graphene oxide doping. Since this improvement in electro-optical properties is associated with the reduction process due to graphene oxide doping, X-ray photoelectron spectroscopy analysis was performed to assess the intensity change of each element. Based on these observations, hybrid thin films doped with graphene oxide emerge as promising candidates for next generation thin film.

The potential role and biological assessment of Cu doped manganese oxide nanoparticles

The potential role and biological assessment of Cu doped manganese oxide nanoparticles

Bismuth doping unlocks stability of copper oxides in anodic reaction: A case analysis of glucose electrooxidation

The instability of transition metal oxides during long-term electrolysis significantly impedes their application in various electrochemical reactions. This study demonstrates an interfacial doping strategy utilizing bismuth to enhance the stability of CuO catalyst during glucose electrooxidation in alkaline media. This methodology reduces activity decay from 55% to 6% after 8 h of electrolysis, lowering charge transfer resistance without compromising the intrinsic catalytic activity of the Cu sites. The enhanced stability can be attributed to the formation of a Cu−O−Bi interface on the catalyst surface, which mitigates the interfacial Cu dissolution, as evidenced by in situ electrochemical impedance analysis. These findings underscore the potential efficacy of bismuth doping strategies in advancing the development of robust and efficient catalysts for anodic catalysis. Furthermore, this research highlights the prospect of employing main group metals as dopants in transition metal oxides, thereby expanding the horizon of possibilities in catalyst design.

Guiding nitrogen doped vanadium pentoxide nanoclusters on cobalt sulfide nano-flakiness as stable seamless interface anode toward highly energy density and durable asymmetric supercapacitors

Interaction of the interface-heterostructures is crucial to rapid ionic conductivity and highly energy density of electrode materials toward supercapacitors. Herein, a novel anode heterostructure is synthesized using cobalt sulfide (CoS) nanoflowers as a substrate for composite nitrogen doped vanadium pentoxide (denoted as N-V2O5@CoS) by combination of hydrothermal and calcination method. As expected, the N-V2O5@CoS electrode possesses superhigh specific surface area that significantly enhances the specific capacitance, and its unique porous interconnected structure not only reduces the volume effect during the cycles, but also greatly enhances the conductivity of electron transfer. The as-prepared N-V2O5@CoS electrode has a specific capacitance of up to 2413.6F/g at a current density of 1 A/g, and can still maintain 87.51 % of the initial capacitance after 5,000 cycles at a high current density of 10 A/g. More importantly, the partial density of states (PDOS) ares obtained through theoretical calculations reveal that the interaction of heterogeneous interfaces is contributed by the p-orbitals of C, O and S and d-orbitals of V and Co. In addition, asymmetric supercapacitor (ASC) with N-V2O5@CoS as the positive electrode and activated carbon (AC) as the negative electrode has a high voltage of 1.7 V, which achieves an outstanding energy density of 71.6 W h kg−1 at a power density of 849.8 W kg−1, showing excellent cycle stability (retain 90.6 % of the initial capacitance after 10,000 charge/discharge cycles). This paper offers novel paradigm for the doping of metal oxides and the development of heterostructures, which provides support for their use as advanced energy storage materials.

Solar light-induced degradation of hazardous organic pollutants using Diospyros kaki mediated green synthesized zirconium doped nickel oxide-zinc oxide nanocomposite

Solar light-induced degradation of hazardous organic pollutants using Diospyros kaki mediated green synthesized zirconium doped nickel oxide-zinc oxide nanocomposite

Design, Fabrication, and Features Investigations of High Concentration of Yttrium Oxide Doped Germanate Tellurate Borate Glass System for Optical and Radiation Shielding Application

Design, Fabrication, and Features Investigations of High Concentration of Yttrium Oxide Doped Germanate Tellurate Borate Glass System for Optical and Radiation Shielding Application

Pemanfaatan Limbah Ban Bekas untuk Sintesis Nanokomposit MnO2/C dengan Metode Hidrotermal sebagai Material Superkapasitor

Activated carbon from waste tires is used as MnO2 metal oxide doping in making MnO2/C-based nanocomposites into high-density and environmentally friendly supercapacitor electrodes. The MnO2/C nanocomposite synthesis process was carried out using the hydrothermal method by varying the mass of activated carbon by 1.25 g, 2.5 g and 3.75 g to determine the optimum results. Based on the results of research that has been carried out, it shows that MnO2/C can be used as a high density supercapacitor electrode. This is in accordance with the XRD test results which show that the MnO2 nanocomposite with the addition of C was successfully synthesized and has an orthorhombic crystalline phase. The SEM test results show that the material has almost the same morphology, namely many protrusions which make each particle have high roughness. The most optimal results were obtained from the MnO2/C-50 variation because it has the highest C element content, namely 39.93%, so it has the highest capacitance value of 5.791 f/g during the CV test. The GCD test shows that electrodes with a carbon variation of 2.5 g have a much longer and constant charge-discharge measurement time. In the EIS test, this variation shows a resistance value that is not too high and not too small, materials that have good storage capacity or capacity have moderate resistance.

Multi-Functional Molybdenum Oxide Doping to Improve the Electrical Characteristics of Indium Oxide Thin Film Transistors

Multi-Functional Molybdenum Oxide Doping to Improve the Electrical Characteristics of Indium Oxide Thin Film Transistors

Schottky Interface Enabled Electrospun Rhodium Oxide Doped Gold for Both pH Sensing and Glucose Measurements in Neutral Buffer and Human Serum.

This study has focused on adjusting sensing environment from basic to neutral pH and improve sensing performance by doping electrodeposited gold (Au) with metal oxide for nonenzymatic glucose measurements in forming a Schottky interface for superior glucose sensing with detailed analysis for the sensing mechanism. The prepared sensor also holds the ability to measure pH with the identical electrospun metal oxide-electrodeposited Au, which composed a dual sensor (glucose and pH sensor) through applying chronoamperometry and open circuit potential methods. The rhodium oxide nanocoral structure was fabricated with an electrospinning precursor solution, followed by a calcination process, and it was mixed with electrodeposited nanocoral gold to form the Schottky interface by constructing a p-n type heterogeneous junction for improved sensitivity in glucose detection. The prepared materials were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectrometry (XPS), etc. The prepared materials were used for both pH responsive testing and amperometric glucose measurements. The rhodium oxide nanocoral doped gold demonstrated a sensitivity of 3.52 μA mM-1 cm-2 and limit of detection of 20 μM with linear range up to 3 mM glucose concentration compared to solely electrodeposited gold for a sensitivity of 0.46 μA mM-1 cm-2 and a limit of detection of 450 μM. The Mott-Schottky method was used for the analysis of an electron transfer process from noble metal to metal oxide to electrolyte in demonstrating the improved sensitivity at neutral pH for glucose measurements due to the Schottky barrier adjustment mechanism at an applied flat band potential of 0.3 V. This work opens a new venue in illustrating the metal oxide/metal materials in the glucose neutral response mechanism. In the end, human serum samples were tested against current commercial glucose meter to certify the accuracy of the proposed sensor.

Solar light driven enhanced in photocatalytic activity of novel Gd incorporated ZnO/SnO2 heterogeneous nanocomposites

The Gd-doped ZnO/SnO2 nanocomposites with various atomic percentages (0, 0.5, 0.8, and 1.2 at%) of gadolinium (coded as GdZS0, GdZS1, GdZS2, and GdZS3) was synthesis via the sol–gel method and explored for photodegradation against dye solutions exposing solar light irradiation. The synthesized nanocomposites were characterized employing the XRD, FTIR, FE-SEM, Raman spectroscopy, BET analysis and UV–Vis spectrophotometer. The FE-SEM results indicated that the formation of nanoparticles to nanoflowers covered with Gd ions was observed with an increased doping concentration of Gd. The optical bandgap was evaluated and found in the range of 3.21–3.27 eV for GdZS nanocomposites. The GdZS nano-photocatalysts were investigated against the degradation of different organic dyes and GdZS3 shows the highest degradation efficiencies of 99.3%, 98.3% and 99.4% towards MO, MB and RhB dyes, respectively at neutral pH in aqueous media. Before and after photodegradation. Biological oxygen demand and chemical oxygen demand tests to make estimations of mineralization. The investigations are very promising for the degradation process in rare earth doped metal oxide nanocomposites. A plausible photodegradation mechanism of synthesized nanocomposites under investigation has also been proposed.

Optimizing Reversible Exsolution and Phase Transformation in Double Perovskite Sr2Fe1.5-xCoxMo0.5O6-δ Electrodes for High-Performance Symmetric Solid Oxide Cells.

Double perovskite (DP) oxides are promising electrode materials for symmetric solid oxide cells (SSOCs) due to their excellent electrochemical activity and stability. B-site cation doping in DP oxides affects the reversibility ofphase transformation and exsolution, which plays a crucial role in the catalyst recovery. Yet, few studies have been conducted on this topic. In this study, the Sr2Fe1.5-xCoxMo0.5O6-δ (CSFM, x = 0, 0.1, 0.3, 0.5) DP system demonstrates modulated exsolution and phase transformation reversibility by manipulating the oxygen vacancy concentration. The correlation between Co-doping level and oxygen vacancy concentration is investigated to optimize the exsolution and phase transformation properties. Sr2Fe1.2Co0.3Mo0.5O6-δ (3CSFM) exhibits reversible transformation between DP and Ruddlesden-Popper phases with a high density of exsolved CoFe nanoparticles under redox atmospheres. The quasi-symmetric cell with 3CSFM shows a peak power density of 1.27Wcm-2 at 850°C in H2 fuel cell mode and a current density of 2.33Acm-2 at 1.6V and 800°C in H2O electrolysis mode. The 3CSFM electrode exhibits robust stability during continuous operation for ≈700h. These results demonstrate the significant role of B-site doping in designing DP materials capable of dynamic phase transformation in diverse environments.

Remarkable chemical adsorption and catalysis of 3D self-supporting Zn-doped NiCo2O4 nanowires for high-performance lithium-sulfur batteries

Lithium-sulfur batteries are one of the most potential next-generation energy storage systems with high theoretical energy density and low cost. However, the lithium polysulfides (LiPSs) dissolution and shuttle effect limit their commercial application. Herein, the Zn-doped NiCo2O4 nanowires grown on carbon cloth (ZNCOCC) are prepared by hydrothermal method and as sulfur host. ZNCO nanowires consisting of stacked nanoparticles and abundant mesopores were grown vertically on carbon fibers. The mesoporous structure of ZNCOCC provides more space to accommodate sulfur and its volume change during charging and discharging, is conducive to electrolyte infiltration and maintains strong adsorption of LiPSs to ensure fast ion transport kinetics. The ZNCOCC displays higher Co3+/Co2+ and Ni3+/Ni2+ ratio compared to NCOCC, and the high-valent metal cations can provide more unsaturated electron orbitals for S binding, causing high adsorption of LiPSs. Density functional theory calculations demonstrate that the Zn doping significantly reduces the band gap, improves the conductivity and increases the LiPSs adsorption energy of NCO. The ZNCOCC/Li2S8 displays a high specific capacity of 1184 mAh g−1 (0.1 C) and a low decay of 0.07 %/cycle after 500 cycles (2 C). This research reveals the rational design of a doped bimetal oxide nanostructure for the improvement of lithium-sulfur batteries.

Effects of Gd2O3 additives on microscopical morphology of ZrB2-SiC sintering ceramic system: Insights for electron transpiration cooling

By manipulating the work function, the dissipation of thermal energy on the material surface can be regulated through Electron Transpiration Cooling (ETC) mechanism. The doping of rare-earth oxide serves as an effective approach for reducing the work function, whereas there is still a lack of comprehensive research into the microstructural morphology of the rare-earth oxides and their correlations with the modifications of the work functions. This study investigates the detailed microscopical structure of Gd2O3 in the ultrahigh-temperature ceramic system (ZrB2-20 vol%SiC). Semi-quantitative composition analyses based on X-ray photoelectron spectra indicate that an increased doping concentration of Gd2O3 is beneficial for the formation of a single solid-state Gd0.18Zr0.82O1.91 phase of ZrB2-SiC system. Atomic-scale scanning transmission electron microscopy (STEM) analyses suggest that Gd2O3 is enriched at the interfaces between SiC and ZrB2 matrix with a nanoscale fibrous morphology composed of alternated Gd2O3 crystals and pores, rendering a continuous microstructure throughout the entire system. This peculiar microstructural morphology is anticipated to facilitate its diffusion along the grain boundary and the formation of Gd2O3 nanolayers at the surface region below the melting points of the ceramic matrix, which can efficiently lower the material work function and reduce the emission energy of the surface electrons during thermal emission through ETC mechanism. The composite with 10 vol% Gd2O3 induces a reduction of the averaged work function of ∼0.49 eV before preforming the thermionic emission experiments. Our results provide valuable insights into the impacts of rare-earth oxide on the ZrB2-SiC matrix, as well as shed light on the feasibility of the ETC mechanism through the efficient design of thermal protection materials.

DFT Guided Design and Preparation of Quasi-Nanocrystalline Hf-La2O3 Cathode with Unprecedented Thermal Emission Performance.

With the guidance of density functional theory (DFT), a high-performance hafnium (Hf) cathode for an air/water vapor plasma torch is designed and the concepts and principles for high performance are elucidated. A quasi-nanocrystalline hexagonal close-packed (HCP) Hf-La2O3 cathode based on these design principles is successfully fabricated via a powder metallurgy route. Under identical voltage and temperature conditions, the thermal emission current density of this quasi-nanocrystalline Hf-La2O3 cathode is ≈20 times greater than that of conventional Hf cathodes. Additionally, its cathodic lifespan is significantly extended. Quasi-nanocrystalline Hf-La2O3 products are manufactured into cathode devices with standard dimensions. This fabrication process is straightforward, requires minimal doped oxides, and is cost-effective. Consequently, the approach offers substantial performance enhancements over traditional Hf melting methods without incurring significantly additional costs.