Combined DFT–experimental, structural and microstructural analysis of Mo-doped NaNiFeMnO2 Layered Oxides

Beyond single modulation: Synergistic Mo doping and S-vacancy engineering in NiS2 for efficient water electrolysis

Ruthenium dioxide (RuO 2 ) is a highly prospective acidic oxygen evolution reaction (OER) catalyst. However, its limited activity and stability impede the broader application, particularly under stringent acidic conditions. In this work, molybdenum (Mo) doping in the RuO 2 lattice (Mo‐RuO 2 ) was used to enhance the Ru‐O covalency, activate lattice oxygen atoms, and steer the OER process toward the lattice‐oxygen‐mediated mechanism (LOM). Optimization of the OER kinetics was achieved with the extent of LOM participation dictated by the concentration of the Mo dopant. Moreover, experimental results indicate that the Mo dopant also improves proton mobility, ultimately accelerating the OER turnover. Remarkably, the Mo‐RuO 2 catalyst exhibits excellent OER activity, with an overpotential of only 199 mV at 10 mA cm −2 , fast kinetics with a Tafel slope of 53.1 mV dec −1 , mass activity of 1341.9 A gRu −1 at 1.53 V (vs. reversible hydrogen electrode) and is highly stable during continuous operation for 180 h in acidic media. Furthermore, proton exchange membrane water electrolyser performance evaluations demonstrated the Mo‐RuO 2 catalyst achieving a notably low cell voltage of 1.713 V at a current density of 1 A cm −2 . This work demonstrates that doping engineering significantly improves the OER activity of RuO 2 by altering the reaction pathway.

Lithium-rich manganese-based (LR) cathodes can deliver high capacity through oxygen redox, but irreversible oxygen release often causes structural degradation, voltage decay, and poor cycling stability. Herein, we propose a Fick's law-guided gradient molybdenum (Mo) doping strategy to simultaneously stabilize bulk lattice oxygen and protect surface interfaces. Gradient-distributed Mo forms strong Mo-O bonds that suppress oxygen loss, while high-valent Mo induces an in situ Li2MoO4 coating and a partial spinel structure, mitigating electrolyte erosion and facilitating Li+ diffusion. The optimized LR@S-Mo cathode delivers a reversible capacity of 195.1 mAh·g-1 with 88.6% retention after 300 cycles at 1C. Theoretical calculations support that Mo doping reduces the Li+ diffusion barrier and enhances oxygen stability. This work provides a unified surface-to-bulk modification route for high-energy-density LR cathodes. In this work, a surface-enriched, depth-dependent Mo distribution is constructed based on a diffusion-guided design, accompanied by an in situ Li2MoO4/spinel surface layer, which correlates with improved electrochemical stability of lithium-rich Mn-based cathodes.

Synergistic molybdenum and iron doping engineering of Ni3S2/Co9S8 hybrid for industrial-scale seawater oxidation

Mechanisms of Molybdenum Doping for Enhancing Fluoride-Induced Pitting Corrosion Resistance in Titanium Alloys for PEMFC Bipolar Plates

Niobium pentoxide (Nb2O5) is a promising pseudocapacitive material for supercapacitor applications due to its high theoretical capacitance and electrochemical stability. However, its practical performance is limited by low electrical conductivity and poor ion transport kinetics. In this work, we report the enhancement of Nb2O5 electrode performance through molybdenum (Mo) doping and thermal calcination. Mo-doped Nb2O5 nanostructures were synthesized via a hydrothermal method followed by calcination at 500 °C. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) confirmed a rougher morphology and homogeneous Mo distribution in the doped sample. X-ray diffraction (XRD) revealed a structural transformation from a deformed orthorhombic phase in pristine Nb2O5 to a more crystalline pseudohexagonal phase in Mo-Nb2O5-500. Electrochemical analysis demonstrated a significant improvement in capacitive behavior, with Mo-Nb2O5-500 achieving a specific capacitance of 55.3 F/g at 5 mV/s, which is five times higher than the undoped sample. All electrodes exhibited stable cycling performance. These results highlight the synergistic role of Mo doping and calcination in enhancing the electrochemical properties of Nb2O5, offering a viable approach for developing high-performance pseudocapacitor electrodes.

Lithium-rich manganese-based (LMR) cathode materials stand as promising candidates for future high-energy-density lithium-ion batteries; however, their commercialization is hindered by inherent electrochemical deficiencies. To address these challenges, strategies such as coating and doping, leveraging their respective modification advantages, have been employed to rectify specific shortcomings of cathode materials. Among these, the synergistic combination of coating and doping strategies has been explored to further enhance modification effects. In this study, we utilized ammonium molybdate to pretreat the surface of LMR cathode materials, achieving an efficient synergy of in situ spinel coating and molybdenum doping, which significantly improved the cycling performance (92.0% capacity retention for 200 cycles at 1 C) and rate capability (150 mA·h/g at 5 C) of the electrode materials. According to testing results and density functional theory (DFT) calculations, the ammonium molybdate pretreatment enhanced the electrical conductivity of the cathode materials. This strategy boasts a straightforward process and achieves an efficient synergism between coating and doping, offering a valuable reference for the practical production of multiply modified electrode materials in the future.

Cobalt-free high-nickel layered cathode materials exhibit great potential for achieving higher energy density, but their cycling stability is largely compromised by inherent interfacial and mechanical instabilities. Molybdenum (Mo) doping could refine the size of primary particle, thus alleviating stress accumulation. Nevertheless, particle refinement leads to an increased specific surface area, making interfacial instability still a critical limitation for cycling stability. Therefore, we constructed a Li2SeO4 modification on the surface of LiNi0.95Al0.04Mo0.01O2 (NiAlMo) via high-temperature reaction between low-melting SeO2 and residual lithium, which suppresses the overgrowth of surface byproducts and mitigates the structural degradation through electronic modulation of surface lattice oxygen. The LiNi0.95Al0.04Mo0.01O2-Li2SeO4 (NiAlMo-Se) delivers 248.2 mAh/g at 0.1 C and 224.2 mAh/g at 0.5 C, with 85.2% capacity retention after 100 cycles within 2.7-4.5 V. And the rate capability of NiAlMo-Se is also significantly enhanced, reaching 178.6 mAh/g at 5 C and 154.4 mAh/g at 10 C. Simultaneous enhancement of mechanical strength and surface stability through microstructure modulation and surface modification represents a viable strategy to stabilize polycrystalline high-nickel layered cathodes.

Rechargeable aqueous zinc‐ion batteries have attracted considerable attention as large‐scale energy storage systems owing to their safety, sustainability, and cost‐effectiveness. However, their practical application has been hindered by limited energy density, primarily determined by cathode performance. Among transition metal oxides, vanadium dioxide (VO 2 ) is particularly appealing due to its layered structure, rich polymorphism, and ability to host Zn 2+ ions reversibly. The thermally driven transition from insulating VO 2 (M) to conductive VO 2 (R) enhances charge transport through the metal–insulator transition (MIT). In this work, molybdenum doping is employed to lower the MIT temperature of VO 2 (M). Doping reduces the MIT temperature of the VO 2 (M) phase to 56.7 °C, resulting in the VO 2 (R) phase. Electrochemical measurements reveal that Mo‐VO 2 (R) cathodes deliver up to ten times higher capacity than the pristine VO 2 (M), with 3Mo‐VO 2 (R) reaching 404.8 mAh g –1 at 0.1 A g –1 . These findings demonstrate that Mo doping serves as a practical approach to modify VO 2 (M) and decrease the MIT temperature, while improving electrochemical performance. Moreover, the heteroatom doping strategy suggests a promising pathway for developing other VO 2 cathodes for efficient rechargeable batteries, which can leverage the heat dissipated in energy storage systems.

This study investigates the influence of high-valence molybdenum (Mo) doping on the optical, electrical, and mechanical properties of aluminum-doped zinc oxide (AZO) thin films. By incorporating an optimal amount of Mo, the surface defects of the MAZO films are significantly reduced, leading to enhanced crystallinity and film-forming quality. These structural improvements directly contribute to increased optical transmittance. In the MAZO films, Mo ions exist predominantly in high oxidation states of +5 and +6. Each doped Mo atom donates multiple free electrons to the lattice, resulting in a marked improvement in electrical conductivity. Additionally, the formation of highly polar Mo–O covalent bonds and the refinement of grain structures synergistically enhance the mechanical performance of the films─including hardness, elastic modulus, wear resistance, and creep resistance─thereby improving both mechanical stability and service life. As a result, MAZO films with outstanding photoelectric and mechanical performance have been successfully fabricated, achieving a low resistivity of 2.355 × 10–4 Ω·cm and a high optical transmittance of 89.0%. These findings demonstrate the potential of Mo-doped AZO films for high-performance optoelectronic and protective coating applications.

Producing hydrogen through water splitting holds significant promise for sustainable energy generation. This study demonstrates a scalable approach for fabricating highly durable nickel-composited NiX (X = Cr and Mo) electrocatalysts using atmospheric plasma spray, a versatile technique that enables rapid deposition with strong adhesion and ensures reliable performance under harsh electrochemical conditions. The electrocatalysts exhibited superior catalytic activity, with NiCr showing overpotentials of 327 mV for oxygen evolution reaction (OER) and 314 mV for hydrogen evolution reaction (HER), while NiMo required only 295 mV for OER and 243 mV for HER. In the two-electrode full-cell configuration, NiMo delivered a lower operating potential of 1.67 V at 20 mA cm–2, whereas NiCr needed 1.76 V. Both electrodes retained stable performance after prolonged cycling, and chronopotentiometric measurements at 50 and 100 mA cm–2 over 50 h further confirmed their excellent durability. In addition, the morphology and wettability changes before and after electrochemical reactions were systematically investigated to understand the catalyst surface behavior. Collectively, the findings indicate the potential of NiX as an effective material for overall water splitting and emphasize plasma spraying as a reliable strategy for fabricating high-performance electrocatalysts.

“Impact of molybdenum doping on the optoelectronic and structural properties of CsPbIBr2 perovskite solar cell” [Physica B: Condensed Matter, 678 (2024), 415758

Influence of molybdenum and chromium doping on WO3 thin films fabricated by spray pyrolysis: Structural and optical characterization

This study presents the development of molybdenum‐doped cerium oxide (Ce1−xMoxO2) thin‐film electrodes for electrochemical energy storage, synthesized via the spray pyrolysis method. Molybdenum doping induces oxygen vacancies (Vo) in the CeO2 structure, significantly enhancing its charge storage capacity. Structural analysis using X‐ray diffraction and Raman spectroscopy confirmed a polycrystalline fluorite‐type structure with decreasing crystallite size as Mo content increased. The Raman peak at 461 cm−1 shifted to lower frequencies, and a broad band between 540 and 630 cm−1, indicative of oxygen vacancies, intensified with doping. Scanning electron microscopy‐energy‐dispersive X‐ray spectroscopy analysis showed good film adhesion, smooth surface morphology, and minimal oxygen deficiency. Optical studies revealed that Mo doping decreased film transmittance (60–80%) and reduced the optical bandgap from 3.28 eV (undoped) to 2.89 eV (6% Mo). Electrochemical performance, evaluated by cyclic voltammetry, demonstrated improved specific capacitance due to increased Ce3+/Vo sites. The best performance was achieved at 6 at% Mo doping, with a specific capacitance of 209.16 F g−1 at 20 mV s−1 and 302.55 F g−1 at 0.5 A g−1. The electrode also exhibited excellent cycling stability, with only 2.73% capacitance loss after 1000 cycles.

Tailoring structural stability of LiMn₂O₄ via molybdenum doping and lithium excess engineering for aqueous lithium-ion batteries

Molybdenum doping modulates the morphology and electronic structure of V2O5 thin films to improve their electrochromic properties

BiVO4 shows significant potential as a photoanode material for photoelectrochemical water-splitting. However, it is hindered by poor charge mobility and water oxidation kinetics. This work explores the effect of molybdenum doping on the charge carrier dynamics of BiVO4 photoanodes, using intensity-modulated photocurrent spectroscopy. The results reveal that an optimal 1% Mo doping improved the charge separation efficiency from 0.27% to 6.7% at an applied bias of 1.23 V vs a reversible hydrogen electrode. It also increased charge transfer efficiency from 4.0% to 69.0%, significantly increasing the external quantum efficiency of the material. Furthermore, Mo incorporation is believed to improve bulk conductivity and passivate the BiVO4 surface by eliminating recombination centers. Studying the change in charge carrier dynamics during accelerated degradation of a 1% Mo:BiVO4 photoanode with a NiFeOOH co-catalyst layer reveals that photocorrosion originates in regions of low charge transfer, caused by uneven co-catalyst distribution. This finding shows that uniform co-catalyst coverage is key toward achieving ultra-stable photoanodes.

Coupling effect of dielectric loss in hollow carbon spheres with simultaneous molybdenum doping for enhanced microwave absorption

Abstract Effect of molybdenum doping on stabilization of cubic phase, chemical stability and protonic conductivity of barium indate (Ba2In2O5) has been investigated in this work. Partial substitution of molybdenum for indium, Ba2In2-xMoxO5+δ (x = 0.1 to 0.6 and δ = 1.5x), has resulted in stabilization of the Ba2In2O5 cubic phase for x = 0.3 and 0.4 compositions. Considering its application as a proton conductor, thermogravimetric experiments have been carried out for moisture pickup evaluation both from stability and protonic conductivity point of view. All of the compositions exhibit an uptake of water below 673 K and also reveal an increase in conductivity with the extent of doping. It is also revealed from the conductivity measurement that activation energy is lowered below 773 K as compared to higher temperature in moist atmosphere which indicated proton conductivity around these temperatures. Graphical abstract