Doping Of Mg Research Articles

Mg-doped SrTaO2N as a visible-light-driven H2-evolution photocatalyst for accelerated Z-scheme overall water splitting

Perovskite SrTaO2N is one of the most promising narrow-bandgap photocatalysts for Z-scheme overall water splitting. However, the formation of defect states during thermal nitridation severely hinders the separation of charges, resulting in poor photocatalytic activity. In the present study, we successfully synthesize SrTaO2N photocatalyst with low density of defect states, uniform morphology and particle size by flux-assisted one-pot nitridation combined with Mg doping. Some important parameters, such as the size of unit cell, the content of nitrogen, and microstructure, prove the successful doping of Mg. The defect-related carrier recombination has been significantly reduced by Mg doping, which effectively promotes the charge separation. Moreover, Mg doping induces a change of the band edge, which makes proton reduction have a stronger driving force. After modifying with the core/shell-structured Pt/Cr2O3 cocatalyst, the H2 evolution activity of the optimized SrTaO2N:Mg is 10 times that of the undoped SrTaO2N, with an impressive apparent quantum yield of 1.51% at 420 nm. By coupling with Au-FeCoOx modified BiVO4 as an O2-evolution photocatalyst and [Fe(CN)6]3−/[Fe(CN)6]4− as the redox couple, a redox-based Z-scheme overall water splitting system is successfully constructed with an apparent quantum yield of 1.36% at 420 nm. This work provides an alternative way to prepare oxynitride semiconductors with reduced defects to promote the conversion of solar energy.

Mg‐ZnO/CNT Nanocomposite as Electrode Materials with Enhanced Electrochemical Performance for Supercapacitor Applications

AbstractThe present research work reported the study of nanocomposites of undoped and Mg‐doped ZnO with CNT as electrode materials for supercapacitor application. The undoped ZnO/CNT and Mg‐doped ZnO/CNT nanocomposites (i.e., 10 % Mg‐doped and 20 % Mg‐doped) were synthesized using a cost‐effective blending‐assisted hydrothermal method. The morphological (FESEM & TEM) studies revealed that the diameter of CNT was ~7 nm and the ZnO nanoparticles were spherical in shape with an average particle size of ~5 nm. In addition, it was also found that 10 % Mg‐ZnO and 20 % Mg‐ZnO had a sheet‐like structure. XRD and FTIR studies further confirmed the successful doping of Mg in ZnO and CNT nanocomposites. BET analysis showed that the value of specific capacitance increased with the increase in surface area. Further, the electrochemical performance of these nanocomposites revealed that the higher doping percentage, 20 % Mg‐ZnO/CNT nanocomposite achieved the highest specific capacitance value i.e., 458.5 F/g at 0.1 A/g current density in 3M H2SO4 electrolytic solution, having a retention of 99.8 % after 12,00 long cycles. In addition, the charge storage mechanism revealed that the as‐synthesized nanocomposites showed both the diffusion‐controlled and capacitive‐controlled behaviors. Thus, a higher value of specific capacitance with excellent cyclic stability indicated the higher efficiency of Mg‐doped ZnO/CNT nanocomposite for future supercapacitor applications.

Synergetic electrochemical behavior of magnesium-doped ZnO nanorods with reduced graphene oxide

In this study, we synthesized magnesium-doped ZnO (Mg-ZnO) nanorods embedded in reduced oxide graphene layers (rGO) using the simplest one-pot hydrothermal method. The composites ZnO/rGO and Mg-doped ZnO-rGO (Mg-ZnO/rGO) are polycrystalline and showed successful doping of Mg in ZnO lattice which expands the ZnO lattice structure helping lithium storage by providing more sites. Mg doping in the ZnO lattice extenuates ZnO volume contraction and expansion which promotes structural stabilization of the electrode during multiple charging-discharging cycles. In composites, ZnO and Mg-ZnO attain the shape of nanorods and tightly interleaved theirselves in the sheet of rGO. XPS showed the dominant peak of C1s of sp2 bonding supporting the formation of reduced GO along with Zn, O and Mg elements. The performance of the materials is evaluated as anode for LIB. The ZnO/rGO anode exhibits a discharge capacity of 445 mAh/g at 100 mA g−1 that was significantly enhanced to 463 mAh/g after doping ZnO with 2 % Mg. With further increasing the concentration of Mg to 4 %, the Mg-ZnO/rGO anode achieves a higher discharge capacity of 520 mAh g−1 with better rate capability than its counterpart electrodes. The synergistic effects between Mg-ZnO and carbon-based nanomaterials are ascribed to the creation of additional contact sites to penetrate electrolyte ions into the electrode, thus resulting in the fast lithium-ion diffusion rate.

Effects of metal element doping on the lubrication behaviors and mechanisms of gallium-based liquid metals

Gallium-based liquid metals (GLMs) are a novel high-end lubricant with low friction coefficient and excellent load-carrying capacity. This paper aims to improve the lubrication properties of GLMs by regulating the frictional interfaces. Six types of GLMs doped with Zn, Mg, Bi, Cu, Ti, or Sc elements are prepared respectively, and the effects of metal element doping on the lubrication behaviors and mechanisms for AISI 440C steel self-mated pairs are investigated in the mixed lubrication regime with a ball-on-three-plate setup. Doping 1 wt% Zn or Cu elements can improve the lubrication properties, with the friction coefficient reduced by 20.3 % and the wear rate reduced by 55.1 % compared with those under eutectic Ga/In/Sn lubrication. However, doping Ti, Sc, Mg, or Bi all reduce the lubrication properties. Doping Zn improves the lubrication properties of GLMs by promoting the adsorption of gallium on the frictional interfaces. Conversely, doping Bi inhibits the adsorption of gallium. The improvement in the lubrication properties of Cu-doped GLM is attributed to the formation of low-hardness CuGa2 particles. The doping of Ti or Sc generates high-hardness TiGa3 or ScGa3 particles, causing three-body abrasive wear. The doping of Mg generates a large number of Mg2Ga5 particles, seriously disrupting the stable lubrication.

Electromagnetic Performance of NiMgCuZn Ferrite for Hyperthermia Application in Cancer Treatment.

Ferrite with high permeability, high magnetic loss, and a low Curie temperature is a highly promising material for hyperthermia applications in cancer treatment. In this work, Ni(0.29-x)MgxCu0.14Zn0.60Fe1.94O3.94 (NiMgCuZn) ferrites were prepared at different Mg ion concentrations. The dependence of the Mg ion contents on the crystal structure, magnetic, and permeability properties of NiMgCuZn ferrite was investigated. Structural characterization showed a high crystallinity of the materials and an increase in the lattice constant with the Mg ion content. The magnetic hysteresis loops revealed that the saturation magnetization decreased with an increasing Mg content. Furthermore, the permeability measurements showed an increase in permeability and magnetic loss with the doping of Mg. More importantly, the Curie temperature of the NiMgCuZn ferrite decreases with the Mg ion content and reaches 42.37 °C for x = 0.26 as well as a real permeability of ∼797.88@1 MHz and a magnetic loss of 0.316@1 MHz, which meet the requirements of tumor hyperthermia.

Sintesis dan Karakterisasi Semikonduktor TiO2 Doping Magnesium dengan Metode Hidrotermal

Semiconductors are materials that range between insulators and conductors in terms of conductivity value. Titanium Dioxide (TiO2) is a semiconductor that is widely applied to various things. TiO2 has the benefits, such as being environmentally stable and inexpensive. TiO2 is photoactive in the range of ultraviolet radiation due to the band gap value of 3.2 eV. However, ultraviolet is only produced from 5% of sunlight. The research aimed to narrow the band gap energy so as to maximize light absorption. This is done by modification with the addition of Mg elements to TiO2 materials at different mass variations of Mg (1%, 1.5%, 2%) to the mass of TiO2 which is often referred to as doping. TiO2 was doped by Mg using a hydrothermal method for 24 hours with a temperature of 180ᵒC, followed by 2 hours of calcination at 400ᵒC. Then, TiO2 and Mg-doped TiO2 particles were characterized by SEM-EDX, FTIR, and UV-Vis. Based on the results of TiO2 and Mg-doped TiO2 particle characterization using SEM, both particles are spherical in shape. The success of Mg doping was identified from the data of EDX characterization, which revealed that the mass % of the Mg component increased with the greater Mg doping concentration on TiO2 particles. There was no structural change following Mg doping on TiO2 particles, as evidenced by the same peak based on the results of FTIR characterization of TiO2 and Mg-doped TiO2 particles. Moreover, a 2% Mg mass doping on pure TiO2 resulted in a decrease in band gap energy to 3.16 eV, in which the pure TiO2 was 3.39 eV. The mass doping of Mg on TiO2 required further optimization to obtain the maximum band gap energy reduction for photocatalytic applications.

Mg-doped LaAlO3 structure: a theoretical investigation of indirect to direct bandgap and brittle to ductile transition

Integrating chemical dopants into a pure lattice has fueled a novel concept of tuning the physical and chemical properties of existing materials under and beyond ambient conditions. By using density functional theory (DFT) calculations, we report the structural, electronic, elastic, and optical properties of pure and Mg-doped LaAlO3 structure (La1- xMgxAlO3 and LaAl1- xMgxO3), respectively, with the doping concentrations of x = 0%, 20%, 40%, 60%, 80%, and 100%. Our results show that the doping of Mg along La sites introduce new band (s, p) in the valence bands that is moved towards the conduction bands with increase of doping ration (at x = 60% with a reduced bandgap of 0.04 eV), as well as indirect to direct bandgap transition along Al sites. The density of states shows that the valence band shifts towards the Fermi level by inducing a metallicity in La1-xMgxAlO3 format at 60% configuration. Elastically, LaAlO3 experiences brittle to ductile transition for both doping systems except LaAl1-xMgxO3 at 40% configuration. The higher ranges of optical peaks for both systems are identified for 0%‒40% ranges as compared to other configurations. Fortunately, this study reveals the tunability of LaAlO3 structure in structural, electronic, elastic, and optical aspects, and also extends the availability of this material for future optoelectronic and mechanical applications.

Photocatalytic precise hydrogenation of furfural over ultrathin Pt/NiMg-MOF-74 nanosheets: Synergistic effect of surface optimized NiII sites and Pt clusters

Optimizing the electronic structure of the surface active sites and introducing functional sites for a photocatalyst are effective strategies to achieve the photocatalytic selective hydrogenation of biomass. Herein, Pt clusters/bimetallic NiMg-MOF-74 (MNM) ultrathin nanosheets were constructed for the photocatalytic precise hydrogenation of furfural (FUR) to furfuryl alcohol (FAL). A representative sample (Pt/MNM-0.25) shows 99.9% conversion of FUR and 99.9% selectivity of FAL. The electron density of surface coordinatively unsaturated NiII atoms in MNM is decreased after the doping of Mg. In situ ATR-IR indicated that the optimized surface NiII sites induced a more effective coordination activation of FUR molecules via the Ni-η1-(O)-furfural coordination. Electrochemical measurements and in situ EPR results reveal that Pt clusters are the functional surface sites for transferring the photogenerated electrons and dissociating H2. The synergistic effect of surface optimized NiII sites and Pt clusters is emphasized. This work successfully achieves the high-efficiency precise hydrogenation of FUR to FAL via designing surface functionalized Pt clusters/bimetallic MOF ultrathin nanosheets.

Computational investigation to explore the effects of metals (Mg, Ca, Sr) doping on phase transition, electronic band structure and their repercussions on optical, elastic and mechanical properties of BaThO3

The effect of metals (Mg, Ca, Sr) doping concentration on phase transition, electronic band structure, and their repercussions on the optical, elastic, and mechanical properties of BaThO3 is presented. At 1.40% doping of Mg, Ca, and Sr-atom, the structure of BaThO3 remains cubic. However, it changes from cubic to a pseudo-cubic tetragonal phase at doping concentrations of 4.22% and 7.04%. A systematic substantial shrinking of the band gap is observed in all cases of doping, and its nature remains direct on the G-symmetry point. The reduction in the band gap is explained by the total density of states (TDOS), partial density of states (PDOS), and elemental partial density of states (EPDOS) in the line of phase transformation. The optical response of a doped compound shows a red shift in the absorption edge, whereas the refractive index increases from 2.067–2.227 with Mg-doping and slightly decreases with Ca and Sr doping. For cubic and tetragonal symmetry, the computed elastic constants follow the mechanical stability criteria for each doping concentration, except at 7.04%Ca doping. Furthermore, the bulk modulus shear modulus Young’s modulus Poisson’s ratio, and anisotropic factor are estimated by utilizing elastic parameters. The value is also determined to assess the ductile/brittle character of pure and doped compounds. Moreover, at 4.22%Ca, 7.04%Ca, and 4.22%Mg doping, non- homogeneity is observed due to negative stiffness and very high values of Poisson’s ratio. The modification in structural, electronic, optical, elastic, and mechanical properties with Ca, Mg, and Sr-doping would make them an appropriate candidate for better optimization in UV filters due to the existence of their absorption spectra in the UV region.

Structure and leakage current behavior of GaFe0.95Mg0.05O3 ceramic

GaFe0.95Mg0.05O3 ceramic sample was synthesized through sol–gel technique. The effect of Magnesium (Mg) doping on the structural and leakage current density of gallium ferrite (GaFeO3) was studied in detail. The structural properties of prepared sample were investigated by X-ray diffraction (XRD) and Raman spectroscopy. The single orthorhombic phase was observed without existence of any impurity phases. Moreover, the same number of Raman modes were observed in the Raman spectra which further confirms the single phase of GaFeO3. The lattice parameters were calculated using Rietveld refinement and revealed the increment in lattice parameters with doping of Mg in GaFeO3. The significant reduction is observed in leakage current density (approximately-four orders of magnitude) with the incorporation of Mg.

Mg doping effects on the microstructure and piezoelectric characteristics of ZnO:Li films deposited at room temperature using an RF sputtering deposition method

In this work, Density functional theory (DFT + U) was used to simulate Mg doped LZO (ZnO:Li 3 mol%) based on an atomic substitution concept. The calculation results indicate the piezoelectric constants e33, e31 and lattice constant a have a tendency to increase significantly due to Mg doping effects. Also, an RF magnetron sputtering system was used to prepare Mg-doped LZO films (ZnO: Li 3 mol%) with Mg doping concentrations of 0, 3, 6, 9 mol% at room temperature. A further analysis shows that when the proposed films are deposited at room temperature, Li atoms will bond with oxygen atoms to form Li2O2 to help to enhance the piezoelectric properties of the films. This is also found to be one of the reasons for the error in the simulated lattice constants.In addition, the doping of Mg induces lateral tensile stress in the ZnO structure. This phenomenon can produce lattice distortion and change the asymmetry of the ZnO atomic center at room temperature, thus improving the piezoelectric properties (piezoelectric coefficient d33 is increased from 4.5 to 26.3 pm/V). The reported d33 value is the highest compared to other reports on ZnO-based films deposited at room temperature.

Influences of Mg concentration in ZnMgO film on energy band alignment at CIGSSe/Zn1-xMgxO interface and performances of CIGSSe solar cells

Zn1-xMgxO buffered CdS free CIGSSe solar cell has been believed to be a new simplified structure solar cell with great potential. ZnMgO film plays an important role. To obtain a high quality Zn1-xMgxO thin film becomes a key issue. In this work, Zn1-xMgxO films with different Mg concentrations were prepared by magnetron co-sputtering, and physical performances of Zn1-xMgxO films were investigated. Meanwhile, CdS free CIGSSe solar cells were prepared based on Zn1-xMgxO buffer layers. The effects of Mg concentration in Zn1-xMgxO buffer layers on device performances, energy band alignment, and interface recombination of CIGSSe solar cells were studied. The results show that although the doping of Mg reduces the crystallinity of Zn1-xMgxO films, it increases the band gap by increasing the conduction band minimum. In Zn1-xMgxO buffered CdS free CIGSSe solar cells by all-sputtering process, the photoelectric conversion efficiency increases first and then decreases with the increase of Mg concentration in the x range from 0 to 0.3, which is mainly attributed to the changes of FF and VOC. Meanwhile, the change of Mg concentration affects the energy band alignment at the CIGSSe/Zn1-xMgxO interfaces. The highest efficiency of 15.2 % of Zn0.8Mg0.2O buffered CdS free CIGSSe solar cell with the energy band difference of 0.27 eV was obtained in this work.

Electronic modulation of fiber-shaped-CoFe2O4 via Mg doping for improved PMS activation and sustainable degradation of organic pollutants

Advanced oxidation processes (AOPs) driven by transition metal oxides are promising systems for the removal of organic pollutants. However, the catalytic activity is still limited by the low redox property of the active site. In this study, a novel and robust fiber-shaped cobalt ferrite catalyst was synthesized through a magnesium doping strategy. Detailed structural characterization and theoretical calculations demonstrated that the doping of Mg into CoFe2O4 maintains the spinel structure but increased the electron density of Co sites due to its similar atomic radius but different electronegativity to Co. Remarkably, the optimized MCFO-0.4 achieved superior capability for peroxymonosulfate (PMS) activation and outstanding performance for the catalytic degradation of Ponceau 2R (PR). Furthermore, the inherent crystal stability and magnetic nature of spinel allows for magnetically reusability and ultra-low cobalt leaching of MCFO-0.4. Radical quenching and EPR results confirmed the involvement of singlet oxygen and hydroxyl radicals during PMS activation, and a possible catalytic mechanism was finally proposed. This work provides a case study on microstructural regulation and electron modulation in spinel catalysts, which may provide now clues to further improve the activity of oxidation catalysts for large-scale wastewater treatment.

Enhanced adsorption of inorganic arsenic by Mg-calcite under circumneutral conditions

Calcite is an important reservoir for arsenic (As) and strongly affects its mobility in various geological environments. However, the method by which bulk As is taken up by calcite needs to be better understood. To broaden our understanding, Mg-containing calcite (Mg-calcite), which is a ubiquitous form of calcite in nature, was investigated to determine its As adsorption capacity. Laboratory experiments were conducted under aerobic and anaerobic conditions using synthetic pure calcite (Ca10Mg0) and Mg-calcite (Ca9Mg1, Ca8Mg2). As speciation (determined using chromatography techniques, such as ion chromatography-hydride generation-atomic fluorescence spectrometry (IC-HG-AFS)) and microscopic characterization (field-emission scanning electron microscopy coupled with energy-dispersive spectroscopy (FE-SEM-EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS)) were coupled to investigate the adsorption capacity and potential mechanisms of As adsorption by Mg-calcite. The results showed that Mg-calcite exhibited an As adsorption capacity that was several times higher than pure calcite, especially for As(III). Based on microscopic characterizations, the substitution of CO3/OH groups with As-O groups and the formation of complexes on the Mg-calcite surface are the dominant mechanisms of arsenate (As(V)) adsorption. The doping of Mg into calcite results in a lattice contraction effect that provides additional space for the substitution of larger As oxyanions for carbonate ions. In parallel, as evidenced by the potentiometric automatic titration results, the presence of Mg in calcite led to an increased density of surface positive charges, which promotes greater adsorption of negatively charged As. In addition to the substitution of CO3 groups with As-O groups, the enhanced adsorption of As(III) by Mg-calcite was also attributed to the larger amount of H-bonding yielded by the addition of Mg. To the best of our knowledge, this is the first experimental investigation to quantify the adsorption of As by Mg-calcite, and it provides new insights into the fate and transport of inorganic As by carbonates in aqueous environments.

Enhanced adsorption of fluoroquinolone antibiotic on the surface of the Mg-, Ca-, Fe- and Zn-doped C60 fullerenes: DFT and TD-DFT approach

The fluoroquinolone (FQ) adsorption on Mg-, Ca-, Fe- and Zn-doped fullerenes is examined by density functional theory (DFT) for the first time. The results indicate that the substitution or doping of Mg, Ca, Fe and Zn atoms on C60 enhances the chemical reactivity and sensitivity toward the FQ. Moreover, the FQ can be physically absorbed at the surface of Mg-, Ca-, Fe- and Zn-doped C60 fullerenes. The adsorption energy reaches the highest value for Ca-doped fullerene, with a level of − 46.63 kcal/mol. It is also found that the electrical conductivity of Ca-doped fullerene increased with the FQ adsorption. As a result, the Ca-doped fullerene can produce an electrical signal at the presence of the FQ which helps to detect it. All these results show that Ca-doped fullerene could be a good candidate for nano biosensor applications.

3D printed magnesium-doped β-TCP gyroid scaffold with osteogenesis, angiogenesis, immunomodulation properties and bone regeneration capability in vivo

Bioceramics have been used in orthopedic surgery for several years. Magnesium (Mg) is an essential element in bone tissue and plays an important role in bone metabolism. Mg-doped bioceramics has attracted the attention of researchers recently. However, the optimal doping amount of Mg in β-TCP and the immunomodulatory property of Mg-doped β-TCP (Mg-TCP) have not been determined yet. In this study, β-TCP scaffolds doped with different contents of magnesium oxide (0wt%, 1wt%, 3wt%, and 5wt%) with gyroid structure were printed by digital light processing (DLP) method, and the physicochemical and biological functions were then investigated. Mg-doping improved the physicochemical properties of the β-TCP scaffolds. In vitro experiments confirmed that the doping of Mg in β-TCP scaffolds promoted the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and angiogenic differentiation of endothelial progenitor cells (EPCs), where the 5Mg-TCP has the optimal properties when using the "one cell type" method. It was also found that all Mg-TCP facilitated the polarization of RAW264.7 cells to the M2 phenotype, especially the 3Mg-TCP. However, 3Mg-TCP displayed the optimal osteogenic and angiogenic potential when using a "multiple cell type" method, which referred to culturing the BMSCs or EPCs in the macrophage-conditioned medium. Finally, the in vivo experiments were conducted and the results confirmed that the 3Mg-TCP scaffolds possessed the satisfying bone defect repair capability both after 6 and 12weeks of implantation. This study suggests that 3Mg-TCP scaffolds provide the optimal biological performance and thus have the potential for clinical translation.

Antibacterial study of Eucalyptus grandis fabricated zinc oxide and magnesium doped zinc oxide nanoparticles and its characterization

Mg-doped zinc oxide and zinc oxide nanoparticles were prepared by using methanolic seed extract from the Eucalyptus grandis plant via a green approach. Phytoconstituents present in seed extract act as capping and stabilizing agents for the biosynthesis of nanoparticles. Doping of Mg to zinc oxide nanoparticles increases the bandgap energy, thus enhancing its chemical, physical and optical properties. Further, it was characterized by various techniques such as scanning electron microscopy giving morphological information about the wurtzite hexagonal structure of bio-synthesized nanoparticles. X-ray diffraction technique tells about the crystalline nature of particles and the average crystallite size for zinc oxide and doped zinc oxide nanoparticles. Mg as a dopant enhances the properties of nanoparticles, thus making it more efficiently applicable as an antibacterial agent against Escherichia coli, gram-negative bacteria.

Doping and compensation in heavily Mg doped Al-rich AlGaN films

Record low resistivities of 10 and 30 Ω cm and room-temperature free hole concentrations as high as 3 × 1018 cm−3 were achieved in bulk doping of Mg in Al0.6Ga0.4N films grown on AlN single crystalline wafer and sapphire. The highly conductive films exhibited a low ionization energy of 50 meV and impurity band conduction. Both high Mg concentration (>2 × 1019 cm−3) and low compensation were required to achieve impurity band conduction and high p-type conductivity. The formation of VN-related compensators was actively suppressed by chemical potential control during the deposition process. This work overcomes previous limitations in p-type aluminum gallium nitride (p-AlGaN) and offers a technologically viable solution to high p-conductivity in AlGaN and AlN.

Structural, optical and antibacterial performance of the Mg doped TiO2 nanoparticles synthesized using sol–gel method

Mg doped TiO2 nanoparticles were synthesized by chemical based sol–gel techniques is to investigate the effects of Mg doping concentration on the structural, optical, antibacterial and luminescence properties of TiO2 nanoparticles. Pure and doped TiO2 samples of various concentration were annealed at 400 °C to achieve the desired phase of crystalline structure. XRD results reveals that the prepared samples were exhibits crystalline nature. The crystallite size was observed around 9.7 nm which decreased to 6.8 nm with an increase the doping concentration of Mg. Optical transmittance increases from 80% to 90% and optical band gap varies from 3 eV to 3.07 eV with doping of Mg in TiO2. The photoluminescence emission exhibit in near UV to blue resign from the pure and doped TiO2 nanoparticles. Red shift observed in PL bands. Antibacterial activity was also examined and studied the effects of concentration on the performance. The tuning the properties of TiO2 with doping of Mg have been discussed in details.

ZnO/MgZnO heterostructure membrane with type II band alignment for ceramic fuel cells

Semiconductor membrane fuel cells are a new promising R&D for solid oxide fuel cells and proton ceramic fuel cells. There is a challenge of the electronic short circuit issue by using semiconductor to replace conventional electrolyte membrane. In this work, type II band alignment of the semiconductor heterostructure based on Mg-doped ZnO and ZnO can, on one hand, block electrons passing through the junction, and on the other hand, trigger the ionic properties of membrane to boost the fuel cell performance. The Mg doping into ZnO creates more oxygen vacancies at the surface of ZnO, leading to enhanced ionic transport, and meaningful fuel cell performance of 673 mW/cm2; while the Mg-doped ZnO/ZnO heterostructure fuel cell has delivered 997 mW/cm2 and OCV 1.04 V at 520 oC. It is worth highlighting that the constructed heterostructure interface, especially the band bending and constituted build-in electric field, plays a pivotal role in enhancing the ionic transport and suppressing the electron passing through the internal device. First principal calculations using density functional theory confirmed the doping of Mg and the formation of heterostructure with ZnO to help for enhancing charge carriers and separations. This work suggests that the constructed type II band alignment or the semiconductor heterostructure is useful for developing advanced fuel cells.