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Transition metal nitrides, especially tantalum nitrides, are pivotal for applications in extreme environments demanding excellent mechanical properties and thermodynamic stability. Among them, θ$\utheta$‐TaN, a high‐pressure polymorph of tantalum nitride with its exceptional bulk modulus (362 GPa) and hardness (31.7 GPa) promises to have many technological uses. Another nitride, Ta3N5${\rm {Ta}}_3{\rm {N}}_5$, has gained importance as a photocatalyst for water splitting using visible light. The Ta–N phase diagram indicates that the thermal decomposition of pure Ta3N5${\rm {Ta}}_3{\rm {N}}_5$ leads to the formation of ε$\uepsilon$‐TaN. However, Ta3N5${\rm {Ta}}_3{\rm {N}}_5$ usually has some amount of oxygen as an impurity mainly due to its synthesis route. We found that the θ$\utheta$‐TaN phase, which is usually observed at high pressures, is formed during the thermal decomposition of oxygen containing Ta3N5${\rm {Ta}}_3{\rm {N}}_5$. The presence of θ$\utheta$‐TaN is verified using several experimental techniques such as X‐ray diffraction, Raman spectra, high‐angle annular dark field scanning transmission electron microscopy (STEM‐HAADF), and electron energy loss spectroscopy (EELS). Elemental distribution analyzed through energy dispersion X‐ray spectroscopy (XEDS) in STEM reveals about 7 at.% of oxygen in θ$\utheta$‐TaN. First‐principle calculations are performed to examine the thermodynamic stability of oxygen substituted θ$\utheta$‐TaN and pure θ$\utheta$‐TaN via formation enthalpies, elastic constants, and phonon dispersion calculations. The computational studies confirm that oxygen in θ$\utheta$‐TaN enhances its thermodynamic stability. The calculated electron localization functions establish the bonding characteristics between Ta, N, and O, confirming the same. [ABSTRACT FROM AUTHOR]

Both sodium‐ion batteries (SIBs) and potassium‐ion batteries (PIBs) are considered as promising candidates in grid‐level energy storage devices. Unfortunately, the larger ionic radii of K+ and Na+ induce poor diffusion kinetics and cycling stability of carbon anode materials. Pore structure regulation is an ideal strategy to promote the diffusion kinetics and cyclic stability of carbon materials by facilitating electrolyte infiltration, increasing the transport channels, and alleviating the volume change. However, traditional pore‐forming agent‐assisted methods considerably increase the difficulty of synthesis and limit practical applications of porous carbon materials. Herein, porous carbon materials (Ca‐PC/Na‐PC/K‐PC) with different pore structures have been prepared with gluconates as the precursors, and the amorphous structure, abundant micropores, and oxygen‐doping active sites endow the Ca‐PC anode with excellent potassium and sodium storage performance. For PIBs, the capacitive contribution ratio of Ca‐PC is 82% at 5.0 mV s−1 due to the introduction of micropores and high oxygen‐doping content, while a high reversible capacity of 121.4 mAh g−1 can be reached at 5 A g−1 after 2000 cycles. For SIBs, stable sodium storage capacity of 101.4 mAh g−1 can be achieved at 2 A g−1 after 8000 cycles with a very low decay rate of 0.65% for per cycle. This work may provide an avenue for the application of porous carbon materials in the energy storage field. [ABSTRACT FROM AUTHOR]

The thin film of indium gallium tin oxide (IGTO) was deposited by the RF magnetron sputtering system with different oxygen flow ratios, which controls the numbers of defects and free carriers to change the characteristics of thin-film transistors ((TFTs). We determined the subgap density-of-states (DOS) from the transfer characteristics curve by the unified subthreshold coupling factor technique to analyze the response of oxygen-related trap sites within the thin films fabricated under different oxygen flows. We used Python to fit the DOS data with a combination of two exponential forms, inferring that, during the increase in the oxygen flow ratio, acceptor-like oxygen-related trap sites can be gradually compensated. The IGTO TFTs exhibit optimized performance when subjected to annealing at 200 °C for 1 h with a 5% oxygen flow ratio, showing a threshold voltage (Vth) of 1.76 V, a field-effect mobility of 0.355 cm2/V s, an impressive on/off drain current ratio of 1.42 × 106, and a subthreshold swing (SS) of 0.665 V/decade. [ABSTRACT FROM AUTHOR]

Abstract Both sodium‐ion batteries (SIBs) and potassium‐ion batteries (PIBs) are considered as promising candidates in grid‐level energy storage devices. Unfortunately, the larger ionic radii of K+ and Na+ induce poor diffusion kinetics and cycling stability of carbon anode materials. Pore structure regulation is an ideal strategy to promote the diffusion kinetics and cyclic stability of carbon materials by facilitating electrolyte infiltration, increasing the transport channels, and alleviating the volume change. However, traditional pore‐forming agent‐assisted methods considerably increase the difficulty of synthesis and limit practical applications of porous carbon materials. Herein, porous carbon materials (Ca‐PC/Na‐PC/K‐PC) with different pore structures have been prepared with gluconates as the precursors, and the amorphous structure, abundant micropores, and oxygen‐doping active sites endow the Ca‐PC anode with excellent potassium and sodium storage performance. For PIBs, the capacitive contribution ratio of Ca‐PC is 82% at 5.0 mV s−1 due to the introduction of micropores and high oxygen‐doping content, while a high reversible capacity of 121.4 mAh g−1 can be reached at 5 A g−1 after 2000 cycles. For SIBs, stable sodium storage capacity of 101.4 mAh g−1 can be achieved at 2 A g−1 after 8000 cycles with a very low decay rate of 0.65% for per cycle. This work may provide an avenue for the application of porous carbon materials in the energy storage field.

Refractory multi-principal element alloys (RMPEAs) have garnered attention for their potential in high-temperature applications. Additive manufacturing (AM) provides opportunities to tailor RMPEAs’ microstructures to enhance these properties. However, controlling defects and addressing the challenges posed by the complex thermal history during the AM process are crucial for optimizing RMPEAs’ performance. This study aims to fabricate a high-quality oxygen-doped NbTiZr alloys using laser powder bed fusion and investigate their microstructure and mechanical properties. Our analysis reveals refined grain sizes and a periodic combination of fine near-equiaxed and columnar grain morphologies in the AM-fabricated alloy. Its substructure is characterized by the coexistence of loosely defined cellular dislocation networks and elemental segregation. Compared to its cast counterpart, the additively manufactured alloy exhibits a combination of high yield strength, excellent tensile ductility, and enhanced work hardening. These attributes make the AM-fabricated oxygen-doped NbTiZr alloy a promising candidate for applications required balanced mechanical properties. Understanding the specific effects of different crystal structures and deformation mechanisms is essential for optimizing AM processes to tailor the microstructure and achieve the desired mechanical performance in various engineering applications.

In this work, we fabricated indium gallium zinc oxide (IGTO) metal-semiconductor-metal (MSM) photodetectors (PDs) with different oxygen flow ratios and investigated and discussed their characteristics. 0% PDs show a high responsivity of 25.75 A/W, but their dark current is very high and their switching time is low. 10% PDs exhibit the highest performance. They show a high photo/dark current ratio of 1.05 × 105 with a low dark current of 1.19 × 10-11 A. Their responsivity is 0.12 A/W and their rejection ratio is 9.38 × 105, which is sufficiently high to ensure the accuracy of distinguishing between UV and visible ranges. Their rising time is 206 s and their falling time is 58 s. It was observed that the response time shortened as the oxygen flow ratio was increased. [ABSTRACT FROM AUTHOR]

Heteroatom doping and defect engineering have been proposed as effective ways to modulate the energy band structure and improve the photocatalytic activity of g-C3N4. In this work, ultrathin defective g-C3N4 was successfully prepared using cold plasma. Plasma exfoliation reduces the thickness of g-C3N4 from 10 nm to 3 nm, while simultaneously introducing a large number of nitrogen defects and oxygen atoms into g-C3N4. The amount of doped O was regulated by varying the time and power of the plasma treatment. Due to N vacancies, O atoms formed strong bonds with C atoms, resulting in O doping in g-C3N4. The mechanism of plasma treatment involves oxygen etching and gas expansion. Photocatalytic experiments demonstrated that appropriate amount of O doping improved the photocatalytic degradation of rhodamine B compared with pure g-C3N4. The introduction of O optimized the energy band structure and photoelectric properties of g-C3N4. Active species trapping experiments revealed ·O2− as the main active species during the degradation. [ABSTRACT FROM AUTHOR]

It is important to develop new metal-free catalysts that are both low-cost and environmentally friendly with high performance. Recently, heterojunction catalysts have been used more than single-component catalysts in catalytic reactions. The current study reports the facile production of a new environmental and green metal-free nanocatalyst by three stages including the synthesis of graphite carbon nitride (GCN) from urea, synthesis of GCN-γ-Al 2 O 3 hybrid composite from GCN and aluminium oxide (γ-Al 2 O 3), and synthesis of O-doped GCN-γ-Al 2 O 3 from the interaction of hybrid GCN-γ-Al 2 O 3 with nitric acid treatment. The obtained O-doped GCN-γ-Al 2 O 3 hybrid material was used to catalyse the green and environmental H 2 production(H 2 -P) from sodium borohydride (NaBH 4) methanolysis for the first time. The chemical compositions and morphology structures of these heterojunction-structured hybrid catalysts were carefully characterized by SEM-EDS, XRD, FTIR, TEM, and XPS analyses, and the catalytic activities and reusability were systematically evaluated. The H 2 generation rate (HGR) values of GCN, GCN-γ-Al 2 O 3 and O doped GCN-γ-Al 2 O 3 catalysts were found as 3486, 5310 and 10080 ml min-1 g-1, respectively. The activation energy (Ea) for the O-doped GCN-γ-Al 2 O 3 catalyst was 35.12 kJ mol-1. Besides, the mechanism of the O-doped GCN-γ-Al 2 O 3 catalyst in the NaBH 4 methanolysis reaction(NaBH 4 -RM) was tried to be clarified. [Display omitted] • O doped GCN-γ-Al 2 O 3 was used for H 2 production from NaBH 4 methanolysis. • HGR values of GCN-γ-Al 2 O 3 and O doped GCN-γ-Al 2 O 3 were 5310 and 10080 ml min-1 g-1. • The activation energy for the O doped GCN-γ-Al 2 O 3 catalyst was 35.12 kJ mol-1. • XRD, SEM-EDS, TEM, FTIR and XPS analyses were used for characterization. [ABSTRACT FROM AUTHOR]

Oxygen-doped ZnIn2S4 nanosheets with a suitable concentration of S-vacancies-coated TiO2 nanopillars (S-O-ZIS/TiO2) are successfully prepared on fluorine-doped tin oxide (FTO) substrates. The S-O-ZIS/TiO2 photoanode achieves a photocurrent density of 1.10 mA cm–2 at 1.23 VRHE under light illumination alongside a high incident photon-to-electron conversion efficiency (IPCE) value of 25.6% in a 1 M KOH electrolyte. The enhanced photoelectrochemical performance can be ascribed to several factors. First, the optimum oxygen doping modifies the energy band structure of ZnIn2S4, enhancing the light adsorption efficiency and facilitating the migration efficiency of the photogenerated carriers. In addition, the elimination of excess surface S vacancies avoids the negative effects of surface trap states, resulting in the efficient separation of photogenerated charges. Furthermore, the intimate connection between ZnIn2S4 and TiO2 accelerates the transport and separation of the photogenerated carriers. This work demonstrates the role of oxygen doping and S vacancies in photocatalysis and provides new insights into the design of high-efficiency photocatalysts. [ABSTRACT FROM AUTHOR]

Oxygen doping strategy is one of the most effective methods to improve the electrochemical properties of nickel–cobalt phosphide (NiCoP)-based capacitors by adjusting its inherent electronic structure. In this paper, O-doped NiCoP microspheres derived from porous nanostructured nickel metal–organic frameworks (Ni-MOFs) were constructed through solvothermal method followed by phosphorization treatment. The O-doping concentration has a siginificant influence on the rate performance and cycle stability. The optimized O-doped NiCoP electrode material shows a specific capacitance of 632.4 F-g−1 at 1 A-g−1 and a high retention rate of 56.9% at 20 A g−1. The corresponding NiCoP-based asymmetric supercapacitor exhibits a high energy density of 30.1 Wh kg−1 when the power density is 800.9 W kg−1, and can still maintain 82.1% of the initial capacity after 10 000 cycles at 5 A g−1. [ABSTRACT FROM AUTHOR]

Monolayer MoS2 has emerged as a highly promising candidate for next-generation electronics. However, the production of monolayer MoS2 with a high yield and low cost remains a challenge that impedes its practical application. Here, a significant breakthrough in the batch production of wafer-scale monolayer MoS2 via chemical vapor deposition is reported. Notably, a single preparation process enables the growth of multiple wafers simultaneously. The homogeneity and cleanliness of the entire wafer, as well as the consistency of different wafers within a batch, are demonstrated via morphology characterizations and spectroscopic measurements. Field-effect transistors fabricated using the grown MoS2 exhibit excellent electrical performances, confirming the high quality of the films obtained via this novel batch production method. Additionally, we successfully demonstrate the batch production of wafer-scale oxygen-doped MoS2 films via in situ oxygen doping. This work establishes a pathway towards mass preparation of two-dimensional materials and accelerates their development for diverse applications. [ABSTRACT FROM AUTHOR]

After remarkable progress over the past decades, perovskite solar cells (PSCs) currently exhibit efficient solar power conversion efficiency. However, the environmental instability of perovskite materials and devices is still a serious issue, impeding the future commercialization of this technology. Herein, why PSCs degrade in air is investigated and it is found that one of the critical reasons for the air‐induced PSC degradation is the doping of the 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobi‐fluorene (spiro‐OMeTAD) hole‐transport layer with oxygen. Photoelectron yield spectroscopy reveals that the hole‐transport level of the spiro‐OMeTAD layer becomes deeper by oxygen doping, increasing an energy barrier for hole extraction. In other words, decreased hole extraction at the perovskite/spiro‐OMeTAD interface induces the degradation of PSCs in air. However, this oxygen‐induced degradation of PSCs is reversible to some extent by storing PSCs in a vacuum to remove oxygen. In contrast, no detectable degradation of the perovskite light absorber is observed after ≈600 h of air exposure from the results of morphological and structural characterizations. These aspects provide a deeper understanding of PSCs degradation, giving insight into improving long‐term durability in air in the future. [ABSTRACT FROM AUTHOR]

The oxygen-doped porous carbon nitride (O-PCN) was prepared via calcinating oxalic acid and urea to activate peroxydisulfate (PS) for abatement of 17α-ethinylestradiol (EE2) under visible light. The results indicated that O-PCN possessed relatively higher specific area (50.48 m2 g−1), larger pore volume (0.168 cm3 g−1), larger average size (14.33 nm) and thinner layer compared to g-C3N4. This structure feather can utilize light more efficiently because more light can penetrate the pore of O-PCN reflect in the pores and reflect. Most importantly, O-PCN has quasi-full-visible-light response (790 nm) compared to pure g-C3N4 (480 nm), which can broaden utilization efficiency of visible light range. In PS/O-PCN/Vis system, 6 mg/L EE2 can be completely removed only within 20 min, and degradation rate constant of EE2 is 6.81 and 2.00 times than those in PS/g-C3N4/Vis and O-PCN/Vis systems. The h+ and ∙O2− are main contributors for EE2 abatement in the PS/O-PCN/Vis system. The effect of anion (Cl−, HCO3−, NO3− and SO42−) and typical natural organic matters (HA and FA) present in water matrixes on EE2 abatement in this system is explored, and the estrogenic activities of treated process is also evaluated by MCF-7 cell viability. [ABSTRACT FROM AUTHOR]

Oxygen atoms usually co-exist in the lattice of hexagonal boron nitride (h-BN). The understanding of interactions between the oxygen atoms and the adsorbate, however, is still ambiguous on improving adsorptive desulfurization performance. Herein, simultaneously oxygen atom-scale interior substitution and edge hydroxylation in BN structure were constructed via a polymer-based synthetic strategy. Experimental results indicated that the dual oxygen modified BN (BN–2O) exhibited an impressively increased adsorptive capacity about 12% higher than that of the edge hydroxylated BN (BN–OH) fabricated via a traditional method. The dibenzothiophene (DBT) was investigated to undergo multi-molecular layer type coverage on the BN–2O uneven surface via π–π interaction, which was enhanced by the increased oxygen doping at the edges of BN–2O. The density functional theory calculations also unveiled that the oxygen atoms confined in BN interior structure could polarize the adsorbate, thereby resulting in a dipole interaction between the adsorbate and BN–2O. This effect endowed BN–2O with the ability to selectively adsorb DBT from the aromatic-rich fuel, thereafter leading to an impressive prospect for the adsorptive desulfurization performance of the fuel. The adsorptive result was in good accordance with Freundlich and pseudo-second-order adsorption kinetics model results. Therefore, the designing of a polymer-based strategy could be also extended to other heteroatom doping systems to enhance adsorptive performance.

We provide a mathematical description, based on d -wave Eliashberg theory, of the strong correlation between the experimentally observed softening of Raman modes associated with in-plane oxygen motions and the corresponding superconducting critical temperature $T_\mathrm{c}$ , as a function of oxygen doping x , in YBa _2 Cu _3 O _x . The theoretical model provides a direct link between physical trends of soft optical A _g (in-plane) oxygen modes, the level of oxygen doping x , and the superconducting $T_\mathrm{c}$ . Different regimes observed in the trend of $T_\mathrm{c}$ vs doping can be related to corresponding regimes of optical phonon softening in the Raman spectra. These results provide further evidence related to the physical origin of high-temperature superconductivity in rare-earth cuprate oxides and to the significant role of electron–phonon coupling therein.

As a category of transition metal-nitrogen-carbon (M-N-C) catalysts, Mn-based single-atom catalysts (SACs) are considered as promising non-precious metal catalysts for stable oxygen reduction reaction (ORR) due to their Fenton-inactive character (versus Fe) and more abundant earth reserves (versus Ni, Co). However, their ORR activity is unsatisfactory. Besides, the structure-activity relationship via tuning the coordination environment of the second coordination shell for transition metal single sites is still elusive. Here, a Mn SAC with O doping in the second-shell of atomically dispersed Mn centers (MnSAC-O/C) as highly efficient and stable ORR catalyst is developed. X-ray absorption spectroscopy combined with theoretical calculations verifies the O doping in the second-shell of Mn center, and reveals the distortion of local environment of Mn center in the MnSAC-O/C. The MnSAC-O/C exhibits high ORR performance with a half-wave potential of 0.898 V, superior to MnSAC-C, commercial Pt/C and most reported non-noble metal-based SACs. More importantly, MnSAC-O/C based zinc-air batteries (ZABs) deliver outstanding durability with stable operation exceeding 930 h. Theoretical calculations confirm that O doping breaks the symmetry of charge distribution of MnN 4 active center and facilitates OH* desorption, thus attributing to the promoted ORR activity., (© 2024 Wiley‐VCH GmbH.)

Here, a rechargeable carbon fluoride battery is demonstrated with unprecedented high rate and long life by oxygen doping and electrolyte formulation. The introductions of Mn 2+ -O catalyst and porous structure during the oxidation process of CF x cathode can promote the splitting of Li-F during charging. By further modulating the electrolyte with triphenylantimony chloride (TSbCl) as anion acceptor and CsF as product modulator, the more readily dissociable CsLiF 2 product instead of LiF is preferentially formed, and the TSbCl-salt protection interface is constructed to confine Li-F based products and reduce fluoride loss at cathode side. These effects endow Li-CF x batteries with durable reversible conversion reaction (for at least 600 cycles), ultrahigh rate performance (e.g., 364 mAh g -1 at 20 A g -1 ) and low charging plateau voltage down to 3.2 V. The cathode exhibits the maximum power density of 38342 W kg -1 and energy density of 1012 Wh kg -1 . Furthermore, this Li-CF x system demonstrates the promising prospects for applications in view of its low temperature operation (e.g., 280 mAh g -1 at -20 °C), low self-discharge ability, large-scale pouch cell fabrication and high cathode loading (5-6 mg cm -2 ), enabling it to move beyond previous role as primary battery and into new role as fast-charging rechargeable battery with high energy density., (© 2024 Wiley‐VCH GmbH.)

Monolayer MoS2 has emerged as a highly promising candidate for next-generation electronics. However, the production of monolayer MoS2 with a high yield and low cost remains a challenge that impedes its practical application. Here, a significant breakthrough in the batch production of wafer-scale monolayer MoS2 via chemical vapor deposition is reported. Notably, a single preparation process enables the growth of multiple wafers simultaneously. The homogeneity and cleanliness of the entire wafer, as well as the consistency of different wafers within a batch, are demonstrated via morphology characterizations and spectroscopic measurements. Field-effect transistors fabricated using the grown MoS2 exhibit excellent electrical performances, confirming the high quality of the films obtained via this novel batch production method. Additionally, we successfully demonstrate the batch production of wafer-scale oxygen-doped MoS2 films via in situ oxygen doping. This work establishes a pathway towards mass preparation of two-dimensional materials and accelerates their development for diverse applications.

Layered transition metal dichalcogenides (TMDs) are promising candidates for aqueous zinc‐based batteries owing to the large interlayer distance. Nevertheless, the low specific capacity of unmodified TMDs due to the high binding energy between host materials and carriers in electrolytes hinder their further development. Herein, a simple method to incorporate oxygen is reported to enhance the specific capacity of MoSe2. The in situ and ex situ characterization results confirm that the oxygen incorporated MoSe2 experiences proton‐dominated insertion electrochemistry during cycling. In addition, the theoretical calculation results demonstrate that the oxygen atoms with high electronegativity can effectively reduce the binding energy of adsorbing H+ and change charge distribution in the interlayer. As a result, incorporating oxygen significantly promotes H+ adsorption and diffusion, and thus greatly increases the specific capacity of MoSe2. This study provides an effective strategy to facilitate the kinetics of TMDs, and thus achieve high‐performance aqueous zinc‐based batteries. [ABSTRACT FROM AUTHOR]

Harnessing the fascinating properties of correlated oxides requires precise control of their carrier density. Compared to other methods, oxygen doping provides an effective and more direct way to tune the electronic properties of correlated oxides. Although several approaches, such as thermal annealing and oxygen migration, have been introduced to change the oxygen content, a continuous and reversible solution that can be integrated with modern electronic technology is much in demand. Here, we report a novel ionic field-effect transistor using solid Gd-doped CeO2 as the gate dielectric, which shows a remarkable carrier-density-tuning ability via electric-field-controlled oxygen concentration at room temperature. In Bi2Sr2CaCu2O8+δ (Bi-2212) thin flakes, we achieve a reversible superconductor–insulator transition by driving oxygen ions in and out of the samples with electric fields, and map out the phase diagram all the way from the insulating regime to the over-doped superconducting regime by continuously changing the oxygen doping level. Scaling analysis indicates that the reversible superconductor–insulator transition for the Bi-2212 thin flakes follows the theoretical description of a two-dimensional quantum phase transition. Our work provides a route for realizing electric-field control of phase transition in correlated oxides. Moreover, the configuration of this type of transistor makes heterostructure/interface engineering possible, thus having the potential to serve as the next-generation all-solid-state field-effect transistor. [ABSTRACT FROM AUTHOR]

The regulation of surface wettability and heteroelement doping have been proved to be effective strategies to enhance photocatalytic H 2 evolution activity of graphitic carbon nitride (CN) based photocatalysts. Herein, we report, for the first time, an organosilica assisted method was adopted to synthesize the superhydrophilic oxygen doped graphitic carbon nitride (O –CN). The presence of organosilica induced simultaneous oxygen-containing groups grafting and oxygen doping within carbon nitride substrate. The grafted oxygen-containing groups improved the surface hydrophilicity and water adsorption. Oxygen doping tailored electronic structure and localized electron distribution, contributing to extended visible light harvesting and elevated photoelectric conversion efficiency. As a result, the H 2 generation rate of O –CN photocatalyst was 5.4 times higher than that of pristine CN photocatalyst attributed to the formation of hydrophilic groups and the oxygen doping. • Superhydrophilic oxygen doped graphitic carbon nitride (O –CN) was synthesized by a novel organosilica assisted strategy. • The organosilica strategy induced abundant oxygen-containing group grafting and enhanced surface wettability. • The presence of organosilica led to oxygen doping, which caused narrowed band gap and impurity energy level formation. • The O –CN photocatalyst exhibits a 5.4 fold increase in the H 2 evolution rate tha that of pristine CN photocatalyst. [ABSTRACT FROM AUTHOR]

This study focuses on Cr 2 O 3 prepared via reactive magnetron sputtering, a direct deposition technique that significantly impacts the microstructure and optoelectronic properties of the films. Reactive sputtering alters grain size, density, and surface morphology, which in turn affects the structural order and stoichiometry. By adjusting the ratio of process gases, particularly the oxygen partial pressure, the stoichiometry of the deposited films was controlled. This is crucial for managing the oxidation state of chromium and the concentration of free electrons. An optimal oxygen partial pressure of 75 % was identified, substantially reducing oxygen interstitial defects in the CrO x materials and enhancing conductivity by nearly two orders of magnitude. Additionally, increasing the oxygen partial pressure helped integrate more oxygen atoms into the lattice, transitioning the electronic structure from a metallic state in CrO 2 to a semiconductive state in CrO 3. This fine-tuning of oxygen doping not only adjusts carrier concentrations but also optimizes the photoelectric properties of the materials, achieving a tailored high band gap of 3.34 eV. This study highlights the potential of reactive magnetron sputtering to customize semiconductor materials through oxygen doping, offering a novel approach to enhance the versatility and application range of chromium oxide materials in advanced technological applications. • Versatile Synthesis: Enhances Cr 2 O 3 film properties via reactive magnetron sputtering. • Stoichiometry Control: Adjusts oxygen pressure to control chromium's oxidation state. • Increased Resistivity: Significantly increases resistivity by optimizing oxygen partial pressure. • Electrical Property Optimization: Tailors electrical properties with precise oxygen doping. [ABSTRACT FROM AUTHOR]

Summary: In this work, oxygen‐doped activated carbons (ACs) are derived from glucose by hydrothermal synthesis (HTS) and a two‐step consecutive activation/treatment. The first KOH activation leads to the formation of well‐developed hierarchical porous structure. The second H2O‐steam treatment controls the fraction of oxygen contents ranging from 3.35 to 10.43 at% by regulating the treatment time and temperature. We propose a reaction for the oxygen reduction during the H2O‐steam treatment, of which the resultant reaction rate increases with the increase of the treatment temperature. The nominal activation energy for the reaction is 18.79 kJ/mol. The symmetric supercapacitors with the ACs of the highest oxygen content exhibit the best electrochemical performances of an optimum specific capacitance of 240.49 F/g in the electrolyte of 1 M H2SO4. However, the symmetric supercapacitors with the ACs of the lowest oxygen content exhibit the best electrochemical performances of an optimum specific capacitance of 171.81 F/g in the organic electrolyte of 1 M Et4BF4 in AN. [ABSTRACT FROM AUTHOR]

Attempts to dope halide perovskites (HaPs) extrinsically have been mostly unsuccessful. Still, oxygen (O2) is an efficient p‐dopant for polycrystalline HaP films. To an extent, this doping is reversible, i.e., the films can be de‐doped by decreasing the O2 partial pressure. Here results are reported, aimed at understanding the mechanism of such reversible doping, as it has been argued that doping involves interaction of oxygen with defects inside bulk HaP. These experimental results clearly point out that O2‐surface interactions suffice to dope the bulk of the films. Such behavior fits what is known for other polycrystalline semiconductors, where surface charge transfer‐adducts can form and be removed. Thus, controlling the O2 partial pressure to which the HaP film is exposed, can, after proper encapsulation, achieve the desired bulk doping of the film. [ABSTRACT FROM AUTHOR]

The urgent demand for energy storage systems fueled the development of lithium‐iodine battery, for it is of high energy/power densities and long lifespan and considered as a promising energy storage system. For advanced lithium‐iodine batteries, a free‐standing metal‐organic frameworks (MOF) derived carbon@carbon cloth (MDC@CC) current collector, without using nonconductive binders, was fabricated via in‐situ calcination. Its meso‐micro porous structure and oxygen doping together restricted the shuttle effect and boosted the redox kinetics, leading to the outstanding long‐term cycle performance of MDC@CC. The major contribution of the capacitive effects at high sweep rates leads to impressive high‐rate performance, exhibiting a high capacity of 308 mAh g−1 at 1 C with Coulombic efficiency close to 100 %. Moreover, in long‐term cycling at 10 C, it displays a high capacity retention of 91 % after 3500 cycles. [ABSTRACT FROM AUTHOR]

In the present study, metal-free catalysts for efficient H 2 generation from NaBH 4 methanolysis was produced for the first time from apricot kernel shells with two-step activation. The first stage of the two-stage activation includes the production of activated carbon with the KOH agent (AKOH), and the second stage includes hydrothermally HNO 3 activation with oxygen doping (O doped AKOH + N). The hydrogen production rate (HGR) and the activation energy (Ea) of the reaction with the obtained metal-free catalyst (10 mg) were determined as 14,444 ml min−1 g−1 and 7.86 kJ mol−1, respectively. The structural and physical-chemical properties of these catalysts were characterized by XRD (X-ray diffraction), SEM (scanning electron microscopy), elemental CHNS analysis, FT-IR (Fourier transform infrared spectroscopy), and nitrogen adsorption analysis. Also, the reusability results of this metal-free catalyst for H 2 production are promising. [Display omitted] • O doped metal-free catalysts based on carbonaceous sample was prepared. • Metal-free catalysts were used to obtain H 2 from NaBH 4 methanolysis. • HGR obtained with O doped metal-free catalysts was 14,444 ml min−1g−1. • Ea value was 7.86 kJ mol−1. [ABSTRACT FROM AUTHOR]

The development of electrocatalysts with low cost, high efficiency, and long-term durability is crucial for advancing green hydrogen production. Transition metal phosphides (TMPs) have been proved to be efficient electrocatalyst, while the improvement in the performance and durability of the TMPs remains a big challenge. Employing atmospheric pressure chemical vapor deposition (APCVD) and phosphorization, FeP/Ti electrodes are fabricated featuring controllable oxygen ingredients (O-FeP/Ti). This manipulation of oxygen content fine-tunes the electronic structure of the catalyst, resulting in improved surface reaction kinetics and catalytic activity. The optimized O-FeP-400/Ti exhibits outstanding HER activity with overpotentials of 142 and 159 mV at -10 mA cm -2 in 0.5 M H 2 SO 4 and 1 M KOH, respectively. Notably, the obtained O-FeP/Ti cathode also displays remarkable durability of up to 200 h in acidic electrolyte with surface topography remaining intact. For the first time, the low-valence titanium oxide (Ti 3 O) interlayer is identified in the composite electrode and ascribed for the superior connection between Ti substrate and the surface O-FeP catalyst, as supported by experimental results and density functional theory (DFT) analysis. This work has expanded the potential applications of transition metal phosphides (TMPs) as a cost-effective, highly efficient and durable catalyst for water splitting., (© 2024 Wiley-VCH GmbH.)

Phase-change random access memory represents a notable advancement in nonvolatile memory technology; however, it faces challenges in terms of thermal stability and reliability, hindering its broader application. To mitigate these issues, doping and structural modification techniques such as phase-change heterostructures (PCH) are widely studied. Although doping typically enhances thermal stability, it can adversely affect the switching speed. Structural modifications such as PCH have struggled to sustain stable performance under high atmospheric conditions. In this study, these challenges are addressed by synergizing oxygen-doped Sb 2 Te 3 (OST) with PCH technology. This study presents a novel approach in which OST significantly improves the crystallization temperature, power efficiency, and cyclability. Subsequently, the integration of the PCH technology bolsters the switching speed and further amplifies the device's reliability and endurance by refining the grain size (≈7 nm). The resultant OST-PCH devices exhibit exceptional performance metrics, including a drift coefficient of 0.003 in the RESET state, endurance of ≈4 × 10 8 cycles, an switching speed of 300 ns, and 67.6 pJ of RESET energy. These findings suggest that the OST-PCH devices show promise for integration into embedded systems, such as those found in automotive applications and Internet of Things devices., (© 2024 Wiley‐VCH GmbH.)

Introduction of hydroxyl-rich porous silica nanosheets (SiNSs) induced the high dispersion of oxygen-doped carbon nitride (OCN) nanoparticles via hydroxyl- and mesopore-dual-confined thermal polymerization of precursor melamine and simultaneous hydroxyl-induced O-doping by replacing the edge N atoms of heptazine. The resultant OCN/SiNS composites possessed enhanced photocatalytic activity for Rhodamine B (RhB) oxidation compared to bulk CN, with a quick reaction within 55 min and an apparent rate constant of 0.073 min–1, mainly owing to the high adsorption of SiNSs, larger specific surface area of highly dispersed OCN nanoparticles, and the adjusted band structure originated from the comprehensive effects of nanoparticle structure and O-doping, which led to a narrowed band gap with strengthened visible-light adsorption and an enhanced photogenerated carrier separation efficiency. Furthermore, in terms of the photocatalytic mechanism, it showed a more reactive oxygen species of singlet oxygen (main) and superoxide radicals (secondary) for effective RhB decomposition, but significantly lowered the oxidative ability of the holes towards RhB. This work suggests the great potential of silica nanosheets as a supporter and inducer in dispersion and structure tuning of carbon nitride for enhanced photocatalytic property. [ABSTRACT FROM AUTHOR]

In this work, the detailed oxygen reduction reaction (ORR) catalytic performance of M-N4−xOx (M = Fe, Co, and Ni; x =1−4) has been explored via the detailed density functional theory method. The results suggest that the formation energy of M-N4−xOx shows a good linear relationship with the number of doped O atoms. The adsorption manner of O2 on M-N4−xOx changed from end-on (x = 1 and 2) to side-on (x = 3 and 4), and the adsorption strength gradually increased. Based on the results for binding strength of ORR intermediates and the Gibbs free energy of ORR steps on the studied catalysts, we screened out two highly active ORR catalysts, namely Co-N3O1 and Ni-N2O2, which possess very small overpotentials of 0.27 and 0.32 V, respectively. Such activities are higher than the precious Pt catalyst. Electronic structure analysis reveals one of the reasons for the higher activity of Co-N3O1 and Ni-N2O2 is that they have small energy gaps and moderate highest occupied molecular orbital energy levels. Furthermore, the results of the density of states reveal that the O doping can improve the electronic structure of the original catalyst to tune the adsorption of the ORR intermediates. [ABSTRACT FROM AUTHOR]

Cobalt sulfides can be considered as auspicious electrode materials for supercapacitors due to the good electrical conductivity and high reversible redox capability. In this study, the O‐doped Co3S4 hollow nanosheets supported on carbon paper (O−Co3S4/CP) are facilely prepared through a suppressed sulfurization method by using CP‐supported Co‐ZIF as the precursor and methanol as the solvent. The hollow nanosheets not only offer fast transport pathways but also provide abundant redox active sites. Furthermore, theoretical calculations indicate that the O doping can enhance the adsorption ability of OH− on O−Co3S4 with electrochemical activity and electrical conductivity improvement. Owing to the advantages of the appropriate composition and unique structure, the as‐made hollow structure O−Co3S4/CP shows a remarkable specific capacitance of 755 F g−1 at a current density of 1 A g−1, while a good rate performance of 65 % capacitance retention at 10 A g−1 can be reached. Moreover, the asymmetric supercapacitors assembled by O−Co3S4/CP and activated carbon electrodes yield an energy density of 21.3 Wh kg−1 with power density of 0.75 kW kg−1. The present work can offer a useful guidance for the exploitation of O doped cobalt sulfides hollow nanosheets for supercapacitors. [ABSTRACT FROM AUTHOR]

• Investigation of optoelectronic properties of ITO with O 2 flow rate variation. • Contact resistivity measurement of ITO/Ag interface as a function of carrier density. • Plasma analysis using Langmuir probe. We have investigated the optoelectronic properties like carrier concentration (N ITO), mobility (µ ITO), work function (ϕ ITO), optical transmission and constants, and sheet resistance (R sh) of tin-doped indium oxide (ITO) films with the variations in the oxygen flow rate during reactive sputter deposition with the Ar:O 2 plasma. Initially, we also analyzed the generated Ar:O 2 plasma parameters (ion energy and density, electron temperature, and energy distribution) using the Langmuir probe. The ITO films' optoelectronic properties were investigated systematically in as-deposited and annealed (150 to 200 °C) conditions with varying O 2 flow rates. By varying the O 2 flow rate, we observed the carrier mobility (µ ITO) of the ITO films in the range of 31-47 cm²/V-s, carrier concentration (N ITO) in the range of 2.16 × 1019 - 5.22 × 1020 cm−3, and resistivity in the range of 3.57 × 10−4 - 8.95 × 10−4 Ω-cm. We were able to separate the roles of grain boundary and ionized impurity scatterings in modifying µ ITO as a function of N ITO in the ITO films. Finally, using the transfer length method, we observed a contact resistivity of ∼3 mΩ-cm² from the ITO/Ag interface at the N ITO of ∼4.08 × 1020 cm−3. [ABSTRACT FROM AUTHOR]

[Display omitted] • Introduction of O atoms increased the electron density and electron precipitation domains of the central Fe atoms. • Primary degradation pathway is the high-valent iron (Fe IV = O) and the electron transfer mechanism. • DFT calculations demonstrate that second-shell-coordinated Fe-N 4 O are the best coordination. • Fe-N 4 O single-atom catalysts exhibited excellent oxidation capacity, tolerance and stability. Modulating the coordination environments and the electronic configurations of the metal centers of single-atom catalysts (SACs) to further improve the activation of peroxomonosulfate (PMS) remains a great challenge. In this work, oxygen (O) atoms were doped into Fe-N 4 single-atom catalysts via oxygen-containing acid precursors to adjust the electronic structure to enhance PMS activation. The prepared Fe-N 4 O single-atom catalysts exhibited excellent oxidation capacity, tolerance, elevated stability and continuous organic oxidation. The primary degradation pathway is the high-valent iron (Fe IV = O) and the electron transfer mechanism. DFT calculations indicated that the adsorption energy and electron transfer number of second-shell-coordinated Fe-N 4 O were much higher than those of one-shell-coordinated Fe-N 3 O. The introduction of O atoms increased the electron density of the central Fe atoms and the electron delocalization domains, which increased the electron transfer capacity. This research provides a method to finely control the coordination environment and electronic structure of Fe-N 4 , revealing the unique dynamic regulation mechanism of heteroatoms for advanced oxidation, and providing a reference for the design of high-efficiency Fenton-like-based catalysts. [ABSTRACT FROM AUTHOR]

The mechanism of O-doping on the electrochemical behavior of activated carbon has been clearly revealed. [Display omitted] • A mild oxidation way was adopted to achieve the O-doping on the activated carbon. • The O-doping is correlated with the quasi capacitance of active materials. • Introducing the C-O and COOH functional groups can improve the wettability of AC. O-doping is important to regulate the electrochemical behavior of activated carbon (AC) used in supercapacitors. However, the clear mechanism and relationship of O-doping on the capacitance behavior of AC seem contradictory and remain undisclosed. This is because when O-doping is carried out, it often causes changes in the physical and chemical properties such as defect state, structure, and specific surface area of AC. The superposition of these factors on capacitance behavior complicates the research problem. Here, a low-temperature oxidation method was adopted to achieve doping of different forms of O-functional groups on the AC with minimal effect on its structure and specific surface area. It can be found that the effect of O-doping on the double-layer capacitance of AC is relatively small, but positively correlated with the pseudocapacitance. This is because the functional groups C-O and COOH by O-doping can not only improve the wettability between the electrolyte and AC, but also combine with cations in the electrolyte to enhance the pseudo capacitance. The influence mechanism of O-doping on the capacitance behavior of AC has been verified in different electrode systems and aqueous electrolytes. This study provides theoretical support for rational O-doping to enhance the electrochemical performance of AC. [ABSTRACT FROM AUTHOR]

Photocatalyst fabrication process plays the central role in photocatalytic hydrogen (H 2) evolution reaction. Herein, we synthesize Na+ functionalized porous graphitic carbon nitride nanorods (Na-CNNR) via a facile one-pot calcination method. The morphology and size of Na-CNNR are controllable by changing the amount of sodium salt; both sodium salt and air are essential to the unique structure and oxygen doping. The obtained Na-CNNR contains abundant oxygen in the graphitic carbon nitride (CN) plane. The optimized Na20-CNNR (20 wt% Na 2 S 2 O 3 •5H 2 O to dicyanamide) photocatalyst exhibits a high surface area with enhanced visible light absorption. Besides, Na20-CNNR displays fast charge transfer and high carrier separation rate characterized by photoluminescence (PL) spectroscopy and electrochemical test. Through time-resolved transient absorption spectra analysis, the trapped unreactive electron accumulation can be highly restrained, favoring efficient active electron de-trapping and transfer. The optimized Na20-CNNR sample exhibits the highest photocatalytic H 2 evolution rate of 7.46 mmol/h/g under visible light irradiation (>400 nm, 100 mW/cm2), which is up to 85 times that of the bare CN and 27 times that of Na+ doped graphitic carbon nitride nanoparticles (Na20–CNNP). Meanwhile, the cyclability tests indicate that Na20-CNNR displays robust stability over 24 h. [Display omitted] • The Na and O Doped porous g-C 3 N 4 nanorod structure was obtained after washing with water without tedious treatment. • Sodium salt and air are essential for g-C 3 N 4 nanorod structure formation and oxygen doping. • Photogenerated electron transfer is highly improved from the picosecond level. • Na20-CNNR exhibits a highly improved photocatalytic H 2 evolution rate of 7460 μmol/h/g. [ABSTRACT FROM AUTHOR]

Polymeric g‐C3N4 is a promising visible‐light‐responsive photocatalyst; however, the fast recombination of charge carriers and moderate oxidation ability remarkably restrict its photocatalytic oxidation efficiency towards organic pollutants. To overcome these drawbacks, a self‐modification strategy of one‐step formaldehyde‐assisted thermal polycondensation of molten urea to prepare carbon‐deficient and oxygen‐doped g‐C3N4 (VC‐OCN) is developed, and the carbon vacancy concentration is well‐controlled by changing formaldehyde dosage. The VC‐OCN catalysts exhibit interesting carbon vacancy concentration‐dependent photocatalytic removal efficiency to p‐nitrophenol (PNP) and atrazine (ATN), in which VC‐OCN15 with appropriate carbon vacancy concentration displays significantly higher pollutant removal efficiency than bulk g‐C3N4. The apparent first‐order rate constant of VC‐OCN15 for PNP and ATN removal is 4.4 and 5.2 times higher than that of bulk g‐C3N4. A combination of the experimental results and theoretic calculations confirm that the synergetic effect of carbon vacancies and oxygen doping sites can not only delay the recombination of charge carriers but also facilitate adsorption of oxygen molecules on the carbon vacancies, which leads to the generation of plentiful active oxygen species including not only superoxide anion radicals but also indirectly formed hydroxyl radicals and singlet oxygen. These active oxygen species play a dominant role in the removal of target pollutants. [ABSTRACT FROM AUTHOR]

For advanced all-solid-state lithium batteries, the solid electrolyte is one of the most critical components that significantly affect battery performance. Herein, solid electrolytes 75Li2S·(25-x)P2S5·xP2O5 (mol%) are successfully prepared via wet chemistry method. Their XRD patterns show that only the crystalline phase β-Li3PS4 is detected for x = 0, 1, 2, 3, 5 mol% and the highest room-temperature ionic conductivity of 2.53 × 10−4 S cm−1 is obtained when x = 2. Next, effects of heat treatment on the structure and electrochemical performance of 75Li2S·23P2S5·2P2O5 are systematically studied. The thermal stability, morphology, structure, and crystal phase of the 75Li2S·23P2S5·2P2O5 electrolyte heated at different temperatures are characterized by thermogravimetric analysis and differential scanning calorimetry (TGA-DSC), SEM, N2 adsorption/desorption, Raman, and XRD. The 75Li2S·23P2S5·2P2O5 electrolyte heat-treated at 320 °C exhibits the highest ionic conductivity of 2.72 × 10−4 S cm−1, the lowest electronic conductivity of 4.8 × 10−9 S cm−1, and excellent electrochemical stability against the metallic lithium electrode. When the heat treatment temperature further increases from 320 to 500 °C, the electrolyte partially decomposes into Li4P2S6 and Li2S. Our results underscore the importance of heat treatment for the synthesis and performance optimization of solid electrolytes for the application of high-energy solid-state batteries. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide has received great attention as a promising non-noble catalyst for electro-catalyzed hydrogen evolution reaction. The active sites originated from the limited edge of crystalline molybdenum disulfide is the key to restrict its HER performance. To increase the active sites of molybdenum disulfide through the heteroatom doping with effective synthetic strategy has become the focus of activity improvement. Herein, a facile and efficient strategy was adopted to synthesize oxygen-doped molybdenum sulfide catalyst by utilizing thiourea and sodium molybdate as precursors. It was found that the number of active sites could be regulated by controlling the dosage ratio of thiourea to sodium molybdate. The doped oxygen and abundant S endows molybdenum sulfide a great deal of lattice disorder or defects, thus providing adequate active sites. When the optimized ratio of thiourea to sodium molybdate (40:1), the double layer value of oxygen-doped molybdenum sulfide reached 34.14 mF/cm2 (mass loading on glassy carbon electrode was 0.142 mg/cm2) which is considered to be proportional to the electrochemical active area. Raman spectroscopy and X-ray photoelectron spectroscopy confirmed the presence of Mo–O bond and bridging S 2 2− bonds which endows molybdenum sulfide with a great deal of lattice disorder or defects, thus providing plentiful active sites. • Oxygen-doped and semi-crystalline molybdenum sulfide materials were synthesized. • Mo–O and bridging S 2 2− bonds were found endows MoSx with plentiful defects. • The obtained materials demonstrate excellent double layer capacitance value. [ABSTRACT FROM AUTHOR]

Microporous carbons were prepared starting from a series of benzene polycarboxylic acids following two strategies: (i) activation- and template-free pyrolysis and (ii) ion-exchange pyrolysis. The proposed synthetic strategies are facile approaches to produce highly microporous carbons that avoid the use of large amounts of corrosive and expensive chemical activators or templates. By varying the number of carboxylic acid groups, the charge balancing species and the degree of deprotonation of the precursors, microporous carbons with diverse morphologies, textural properties and oxygen contents were obtained and their CO 2 and N 2 sorption properties were assessed. The abundant micropores made the materials suitable for CO 2 adsorption at low pressure and ambient temperature, achieving CO 2 uptake as high as 4.4 mmol g−1 at 25 °C and 1 bar, competitive with those reported for porous carbons produced using large excess of alkali metal based activating agents. It was found that high performance, in terms of CO 2 uptake and CO 2 /N 2 selectivity, was linked to the simultaneous presence of large ultra-micropore volume and high oxygen content in the sorbents. This suggests that the interplay of ultra-microporosity and oxygen doping matters more than the two features taken singularly in determining the CO 2 /N 2 separation properties of porous carbons at low pressure. Image 1 [ABSTRACT FROM AUTHOR]

Abstract In this work, the high electrochemical activity induced by doping different contents of oxygen on the surface of graphene sheets embedded carbon (GSEC) film is studied, which is prepared by electron cyclotron resonance (ECR) plasma sputtering system under electron irradiation. Transmission electron microscopy observation and Raman analysis confirm that doping oxygen induced more graphene edges and oxygen‐containing functional groups on the surface. The electrochemical activities of the films are measured in the Fe(CN)64–/3– redox system and the results show that a proper doping content of oxygen is beneficial to reduce the oxidation‐reduction peak separation. The surface O‐doped GSEC film with 5% content realizes the simultaneous detection of uric acid (UA), xanthine (XA) and hypoxanthine (HXA) with high sensitivity. The mechanism could be that the isolated electron at graphene edge and the polar fraction of oxygen‐containing functional groups provide more active sites to accelerate the electron transfer. These results indicate that surface O‐doped GSEC films are promising electrode materials to construct sensitive electrochemical biosensors.

In this work, the high electrochemical activity induced by doping different contents of oxygen on the surface of graphene sheets embedded carbon (GSEC) film is studied, which is prepared by electron cyclotron resonance (ECR) plasma sputtering system under electron irradiation. Transmission electron microscopy observation and Raman analysis confirm that doping oxygen induced more graphene edges and oxygen‐containing functional groups on the surface. The electrochemical activities of the films are measured in the Fe(CN)64–/3– redox system and the results show that a proper doping content of oxygen is beneficial to reduce the oxidation‐reduction peak separation. The surface O‐doped GSEC film with 5% content realizes the simultaneous detection of uric acid (UA), xanthine (XA) and hypoxanthine (HXA) with high sensitivity. The mechanism could be that the isolated electron at graphene edge and the polar fraction of oxygen‐containing functional groups provide more active sites to accelerate the electron transfer. These results indicate that surface O‐doped GSEC films are promising electrode materials to construct sensitive electrochemical biosensors. [ABSTRACT FROM AUTHOR]