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Although crystal facet engineering is extensively studied in energy and environmental technologies, the in‐depth understanding of intrinsic mechanisms governing crystal facet heterojunctions in tuning band alignments is still limited. Here, novel Bi5O7NO3 crystals exposing tailor {080} facets are synthesized via NH4+‐assisted self‐confined construction. It has been confirmed that NH4+ ions selectively adsorb on the {141} facets, inversely inducing the growth of desired {080} crystal facets, while the tailored {080} facets facilitate the generation of oxygen vacancies. The controllable concentration of oxygen vacancies, influenced by different exposed facets, can optimize the relative positions of Fermi levels and shift the photoelectron transfer route between the {141} and {080}‐OV facets from type‐II to S‐scheme, thus triggering rapid charge transport channels and effectively suppressing electron‐hole recombination. DFT calculation verifies that the energy barrier for the *COOH formation on Bi5O7NO3‐{080}‐OV is the lowest, thereby promoting the generation of CO. The well‐designed Bi5O7NO3 crystals with the optimal {080}/{141} facet ratio exhibit a 3.8‐fold enhancement in photocatalytic CO2 reduction, compared to traditional Bi5O7NO3 dominated by the {141} facets. This work offers new insights into the regulation of band alignments at heterointerfaces and the design of high‐efficiency photocatalysts. [ABSTRACT FROM AUTHOR]

Owing to kinetic‐sluggish nature of electrocatalytic oxygen transformation processes, it is pivotal to develop durable and efficient bifunctional air electrode catalysts for fabricating high‐performance Zn–air batteries (ZABs). In this work, oxygen vacancy (Ov) induced Mn(III) sites optimization is achieved via nano‐micro structure modulation. Protonated carbon nitride (p‐C3N4) is applied as a structure‐stiffening module to immobilize α‐MnO2 on N/P‐doped active carbon (NPAC) and induce Ov construction. X‐ray adsorption spectra (XAS) disclose the formation of Ov and Mn(III) sites in MCC, the unit coordination structure is well maintained with the aid of a dual‐carbon strategy. Mn(III) sites efficiently catalyze oxygen reduction/evolution reaction (ORR/OER), MCC shows high half‐wave potential (E1/2) of 0.88 V for ORR and low potential at 10 mA cm−2 (Ej = 10) of 1.64 V for OER. According to density functional theory (DFT) simulations analysis, the gorgeous bifunctional activity is owing to that optimized charge distribution facilitates the intermediates transformation. Aqueous ZABs based on MCC manifests high peak power density of 452 mW cm−2 and durable cycling stability of 1640 h. Quasi‐solid‐state ZABs based on MCC also show satisfactory performances (175 mW cm−2, 105 h). This work provides the route to develop efficient and durable electrocatalyst for constructing ZABs with long lifespan and high‐power‐density. [ABSTRACT FROM AUTHOR]

[Display omitted] Ce-based three-dimensional (3D) mesoporous microspheres with Mn homogeneous incorporation were synthesized. The CeMn-0.4, characterized by a Ce/Mn molar ratio of 6:4, demonstrated exceptional catalytic activity and stability. The formation of CeMn solid solution strengthened the Ce-Mn interaction, yielding higher concentrations of Ce3+ and Mn4+. Mn4+ initiated toluene preliminary activation owing to its robust oxidative properties, while Ce3+ contributed to oxygen vacancy generation, enhancing the activation of gaseous oxygen and lattice oxygen mobility. Integrating experiments and Density Functional Theory (DFT) calculations elucidated the oxygen reaction mechanisms. A portion of oxygen was converted into surface reactive oxygen species (O ads) that directly oxidized toluene. Additionally, the presence of oxygen vacancies promoted the participation of oxygen in toluene oxidation by converting it into lattice oxygen, which was crucial for the deep oxidation of toluene. Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS) indicated the accumulation of benzene-ring intermediates on the catalyst surface hindered continuous toluene oxidation. Thus, the abundant oxygen vacancies in CeMn-0.4 played a pivotal role in sustaining the oxidation process by bolstering the activation of gaseous oxygen and the mobility of lattice oxygen. [ABSTRACT FROM AUTHOR]

HfO2-based ferroelectric materials as the most promising candidate for the ferroelectric memories, have been widely studied for more than a decade due to their excellent ferroelectric properties and CMOS compatibility. In order to realize its industrialization as soon as possible, researchers have been devoted to improving the reliability performance, such as wake up, imprint, limited endurance, et al. Among them, the breakdown characteristic is one of main failure mechanisms of HfO2-based ferroelectric devices, which limits the write/read reliability of the devices. Based on this, we systematically studied the effect of thickness on the time-dependent dielectric breakdown (TDDB) tolerate capability of HfO2–ZrO2 (HZO) FE films under both forward and reverse electrical stress conditions. The thickness of HZO FE film ranged from 6 to 20 nm. Our findings reveal that decreasing the thickness of the HZO FE film leads to an improvement in TDDB tolerance capability which is attributed to the fact that higher density of oxygen vacancies in thinner HZO FE films can effectively inhibit the generation of new oxygen vacancies and the growth of conductive filaments, thus effectively improving the TDDB characteristics. These results provide a potential solution for mitigating breakdown characteristics of HfO2-based ferroelectric devices in memory applications. [ABSTRACT FROM AUTHOR]

The pursuit of high-performance piezo-photocatalysts through structural modifications has been a focal point of investigation within the realm of related scientific disciplines. In this study, we successfully designed Er-doped Bi 0.5 Na 0.5 TiO 3 –BaTiO 3 combined with rare earth ion doping and solid solution modification, and the prepared particles exhibited homogeneous grain sizes and optimized concentrations of oxygen vacancies (O V). The synergistic incorporation of O V (accelerator for catalytic reaction) and Er3+ results in an impressive 12-fold enhancement of the piezo-photocatalytic rate when degrading the Rhodamine B dye. The optimal composition 0.96BNT-0.04BT-Er demonstrates outstanding electrochemical properties, including a superior photocurrent response and minimal impedance, highlighting its exceptional performance in piezo-photocatalysis. The fundamental enhancement in catalytic performance can be attributed to the reconfiguration of the band structure of 0.96BNT-0.04BT-Er, which has been meticulously calculated utilizing DRS and VB-XPS and the internal mechanism was explained in detail. This research serves as a source of inspiration for the investigation of solid solutions among piezo-photocatalysts and sheds light on the vital role of band structure in governing catalytic performance. [ABSTRACT FROM AUTHOR]

A highly sensitive and repeatable humidity sensor that can measure relative humidity at room temperature (25 °C) was fabricated using activated carbon-ZnO (AC/ZnO) nanocomposites. The AC/ZnO nanocomposites with high oxygen vacancies were prepared by a facile one-pot synthesis method through carbonization of ZnCl 2 -impregnated biomass precursor. The sensor exhibited a better response (96 % at 0.5 V biasing), short response time (17.4 s), and recovery time (32.1 s). The same 96 % relative response at 0.5V biasing for all four consecutive cycles was observed without losing the response-recovery time, indicating excellent repeatability. On the other hand, biomass-derived single-phase activated carbon (AC) did not respond to humidity change at room temperature. The improved humidity sensing in AC/ZnO nanocomposites was ascribed to the synergistic effects of increased oxygen vacancies, increased active sites in the AC phase, and the formation of p–n heterojunction at the composite interface, substantiated with X-ray diffraction (XRD), Raman and X-ray photoelectron spectroscopy (XPS) studies. The sensing mechanism of AC/ZnO nanocomposite was discussed based on the enhanced reduction of H 2 O by adsorbed O 2 − at AC/ZnO heterojunction, leading to increasing sensor resistance. [Display omitted] [ABSTRACT FROM AUTHOR]

Bi/BiOCl with oxygen vacancies composite was synthesized through a facile and rapid in situ surface reduction of BiOCl, utilizing NaBH4 as the reductant. The reduction process yielded metallic Bi nanoparticles on the surface of BiOCl and meanwhile created the oxygen vacancies within the BiOCl lattice. As a consequence, the as‐synthesized Bi/BiOCl composites exhibited a substantially enhanced visible‐light absorption capacity, whereas pure BiOCl was only responsive to ultraviolet light. Additionally, the Bi/BiOCl composite demonstrated a markedly accelerated photodegradation rate of Rhodamine, exceeding that of pure BiOCl and P25 by a factor of 6.10 and 19.74, respectively. The density functional theory (DFT) calculation was carried out to estimate the band structural and electronic properties of samples. Based on systematic analysis, the underlying mechanism was attributed to the extended responsive light range due to the surface plasma resonance of metallic Bi and the formation of oxygen vacancy energy level. Moreover, the electron sink effect of Bi nanoparticles was found to suppress the recombination of photoinduced charges, further contributing to the enhanced photocatalytic performance of Bi/BiOCl. [ABSTRACT FROM AUTHOR]

[Display omitted] Phase junctions exhibit great potential in photocatalytic energy conversion, yet the narrow light response region and inefficient charge transfer limit their photocatalytic performance. Herein, an anatase/rutile phase junction modified by plasmonic TiN and oxygen vacancies (TiN/(A-R-TiO 2 -Ov)) is prepared through an in-situ thermal transformation from TiN for efficient photothermal-assisted photocatalytic hydrogen production for the first time. The content of TiN, oxygen vacancies, and phase components in TiN/(A-R-TiO 2 -Ov) hybrids can be well-adjusted by tuning the heating time. The as-prepared photocatalysts display a large specific area and wide light absorption due to the synergistic effect of plasmonic excitation, oxygen vacancies, and bandgap excitations. Meanwhile, the multi-interfaces between TiN, anatase, and rutile provide built-in electric fields for efficient separation of photoinduced carriers and hot electron injection via ohmic contact and type-Ⅱ band arrangement. As a result, the TiN/(A-R-TiO 2 -Ov) photocatalyst shows an excellent photocatalytic hydrogen generation rate of 15.07 mmol/g/h, which is 20.6 times higher than that of titanium dioxide P25. Moreover, temperature-dependent photocatalytic tests reveal that the excellent photothermal conversion caused by plasmonic heating and crystal lattice vibrations in TiN/(A-R-TiO 2 -Ov) has about 25 % enhancement in photocatalysis (18.84 mmol/g/h). This work provides new inspiration for developing high-performance photocatalysts by optimizing charge transfer and photothermal conversion. [ABSTRACT FROM AUTHOR]

Noble metal like Pt or Au deposited on reducible oxides like TiO2 is one of the promising catalysts for CO oxidation, which has many applications including developing long-life sealed-off CO2 lasers, pollution control, etc. Catalytic oxidation of CO is pre-requisite for sealed-off CO2 lasers, because dissociation of lasing CO2 molecules in gas discharge decreases the laser power and may kill laser action in few minutes. Hence, this study was aimed to investigate the CO oxidation efficiency of in-house prepared Pt–TiO2 and Au–TiO2 catalysts, both at room temperature and under discharge conditions. The results of XPS and CO2 conversion measurements revealed that the post-reduction of catalyst plays a very important role for increasing the Pt0 and efficiency of CO oxidation to about 80%. Importantly, in the presence of gas discharge, considerably higher catalytic performance was observed for Pt–TiO2 catalyst with respect to their performance at room temperature and commercial gold (Au)-coated catalyst present in CO2 laser tubes. [ABSTRACT FROM AUTHOR]

A significant challenge in developing high-performance hybrid supercapacitors (HSCs) is the need to reasonably construct advanced architectures that consist of various components and exhibit superior electrochemical capacitance performance. The FeCoNi-layered double hydroxide (FeCoNi-LDH) porous material has a specific capacitance of 1960 F·g−1 when used as the anode material at 1 A·g−1. The FeCoNi-LDH material exhibits nanoplates with a distinct spindle morphology on their surface. Due to the combined action of the three metals and abundant oxygen vacancies, they exhibit unique rate performance and cycle stability. The electronic structure of LDH and the regulation of oxygen vacancy were confirmed by density functional theory (DFT) calculations. This suggests that the strength of hydroxide can reduce the energy required for oxygen vacancy formation in FeCoNi-LDH nanosheets and enhance ion and charge transfer, as well as electrolyte adsorption on the electrode surface. The FeCoNi-LDH//activated carbon (AC) HSC has an energy density of 53.2 Wh·kg−1 at a power density of 800 W·kg−1, surpassing other devices composed of comparable materials during the same timeframe. This study made significant advances in the design and synthesis of a ternary LDH porous structure with distinct oxygen vacancies, as well as its potential application in electrochemical energy storage. [ABSTRACT FROM AUTHOR]

Perovskite oxides play a crucial role as catalysts in the oxygen evolution reaction (OER) owing to their distinctive structure and diverse physical and chemical characteristics. Currently, enhancing the electronic structure and specific surface area of the perovskite surface through strategic regulation poses a significant challenge in the advancement of perovskite catalyst development. Here, we propose a novel method for enhancing the OER activity of LaCoO 3 (LCO) perovskite through atomic doping and interface engineering. The La 0.6 Sr 0.4 CoO 3 –FeOOH (Fe-LSCO) composite exhibits a notable enhancement in electrocatalytic performance, manifesting a low overpotential of 296.3 mV for the oxygen evolution reaction (OER) at a current density of 10 mA cm−2, while maintaining a high level of activity for a duration of 120 h. The enhanced activity of Fe-LSCO can be attributed to oxygen vacancy defects and the increase of the active site caused by A-site-doping and amorphous nanosheets of FeOOH, which synergistic effect reduces the energy barrier for water dissociation. The highly disordered surface and high surface energy of amorphous FeOOH render it highly active. This study presents a viable interface engineering approach for manipulating the reconstruction of the active phase in high-performance perovskite-based electrocatalytic materials. [Display omitted] • Sol-gel and solution soaking treatment were used to fabricate Fe-LSCO. • The doping of Sr changes the spin state of Co ion. • The amorphous hydroxyl iron oxide can improve hydrophilicity and BET. • Fe-LSCO electrode demonstrates outstanding durability and stability. [ABSTRACT FROM AUTHOR]

Efficient non-precious metal electrocatalysts are crucial for hydrogen production through water electrolysis. Combining a superhydrophilic electrocatalyst with oxygen vacancy and a conductive carbon matrix is significant for NiFe LDH-based oxygen evolution reaction (OER) applications. In this study, NiFe LDH nanoflowers and Co-doped NiFe LDH nanoneedles were synthesized on graphite felt through an in-situ self-assembly strategy. Further results have shown that doping Co into NiFe LDH nanoarrays significantly enhances the specific surface area and oxygen vacancy density, while the graphite felt serves as a conductive scaffold and prevents active sites detachment. Oxygen vacancies in Co 3 –Ni 7 Fe 3 LDH/TGF adjust the electronic configuration, and superhydrophilicity promotes effective electrolyte diffusion. This synergy endows Co 3 –Ni 7 Fe 3 LDH/TGF with excellent OER performance, lower overpotential of 252 mV (10 mA cm−2), a Tafel slope (63.13 mV), and stability at high current densities. This research provides a new perspective for utilizing non-precious metal catalysts on carbon substrates for hydrogen production. [Display omitted] • Co–NiFe LDH was in-situ grown on graphite felt by self-assembly strategy. • Incorporating Co increases the density of oxygen vacancies in NiFe LDH. • Nanoneedle structure boosts specific surface area and provides many active sites. • Co 3 –Ni 7 Fe 3 LDH/TGF shows a low overpotential of 252 mV at 10 mA cm−2 for OER. • Superhydrophilic Co 3 –Ni 7 Fe 3 LDH/TGF shows robust stability at high current density. [ABSTRACT FROM AUTHOR]

In recent years, defective TiO2 has caught considerable research attention because of its potential to overcome the limits of low visible light absorption and fast charge recombination present in pristine TiO2 photocatalysts. Among the different synthesis conditions for defective TiO2, ambient pressure hydrogenation with the addition of Ar as inert gas for safety purposes has been established as an easy method to realize the process. Whether the Ar gas might still influence the resulting photocatalytic properties and defective surface layer remains an open question. Here, we reveal that the gas flow ratio between H2 and Ar has a crucial impact on the defective structure as well as the photocatalyic activity of TiO2. In particular, transmission electron microscopy (TEM) in combination with electron energy loss spectroscopy (EELS) revealed a larger width of the defective surface layer when using a H2/Ar (50 %–50 %) gas mixture over pure H2. A possible reason could be the increase in dynamic viscosity of the gas mixture when Ar is added. Additionally, photoinduced enhanced Raman spectroscopy (PIERS) is implemented as a complementary approach to investigate the dynamics of the defective structures under ambient conditions which cannot be effortlessly realized by vacuum techniques like TEM. [ABSTRACT FROM AUTHOR]

The prodigious employment of fossil fuels to conquer the global energy demand is becoming a dreadful threat to the human society. This predicament is appealing for a potent photocatalyst that can generate alternate energy sources via solar to chemical energy conversion. With this interest, we have fabricated a ternary heterostructure of Ti3C2 nanosheet modified g‐C3N4/Bi2O3 (MCNRBO) Z‐scheme photocatalyst through self‐assembly process. The morphological analysis clearly evidenced the close interfacial interaction between g‐C3N4 nanorod, Bi2O3 and Ti3C2 nanosheets. The oxygen vacancy created on Bi2O3 surface, as suggested by XPS and EPR analysis, supported the Z‐scheme heterojunction formation between g‐C3N4 nanorod and Bi2O3 nanosheets. The collaborative effect of Z‐scheme and Schottky junction significantly reduced charge transfer resistance promoting separation efficiency of excitons as indicated from PL and EIS analysis. The potential of MCNRBO towards photocatalytic application was investigated by H2O2 and H2 evolution reaction. A superior photocatalytic H2O2 and H2 production rate for MCNRBO is observed, which are respectively around 5 and 18 folds higher as compared to pristine CNR nanorod. The present work encourages for the development of a noble, eco‐benign and immensely efficient dual heterojunction based photocatalyst, which can acts as saviour of human society from energy crisis. [ABSTRACT FROM AUTHOR]

As an organic compound, it has significant application value. Triethylamine (TEA) is widely used in chemical, pharmaceutical, pesticide, dye, and other fields. However, its toxicity makes its impact on the environment and human health undeniable. Therefore, developing low-power, high response, ultraselectivity, and stability sensors for detecting this toxic gas is crucial for healthcare and environmental monitoring. In this work, we synthesized Ru-doped ZnO (Rux%ZnO) nanoparticles, which exhibited multiple enhanced sensing performance for TEA detection. Typically, the response value (Ra/Rg) of the Ru0.05%ZnO sensor to 50 ppm TEA at 260 °C is as high as 2907, which is nearly 15 times higher than pristine ZnO. In addition, compared with the ZnO sensor, the optimal operating temperature of the Ru0.05%ZnO sensor has also been reduced by 80 °C. Exceptionally, under the condition of a relative humidity of 85% (set at 25 °C), the Ra/Rg of the Ru0.05ZnO sensor to 10 ppm of TEA is still up to 126. Finally, the gas sensing mechanism of Rux%ZnO sensors to TEA was explored. [ABSTRACT FROM AUTHOR]

Ag dopants and V o in V o -NiFeAg-LDH/CC strengthen the O* adsorption by enriching the electron density around the active sites, further promoting the deprotonation step from OH* to O* and accelerating the catalytic process for OER. [Display omitted] • Ag dopants together with V o structures enrich the electron density around the active sites in V o -NiFeAg-LDH/CC. • The deprotonation step from OH* to O* during OER has been accelerated through Ag and V o co-modification. • Systemic DFT calculations decouple individual effects of Ag dopants and V o in V o -NiFeAg-LDH/CC. • The current density of V o -NiFeAg-LDH/CC is 3.23 times than that of IrO 2 at 2 V under alkaline flow electrolyzer. The demand for clean energy sources has driven focus towards advanced electrochemical systems. However, the sluggish kinetics of the oxygen evolution reaction (OER) constrain the energy conversion efficiency of relevant devices. Herein, a one-step method is reported to grow oxygen vacancies (V o) rich NiFeAg layered double hydroxides nanoclusters on carbon cloth (V o -NiFeAg-LDH/CC) for serving as the self-supporting electrode to catalyze OER. The OER performance of V o -NiFeAg-LDH/CC has been remarkably enhanced through Ag and V o co-modification compared with pristine NiFe-LDH, achieving a low Tafel slope of 49.7 mV dec−1 in 1 m KOH solution. Additionally, the current density of V o -NiFeAg-LDH/CC is 3.23 times higher than that of the state-of-art IrO 2 at 2 V under an alkaline flow electrolyzer setup. Theoretical calculations and experimental results collectively demonstrate that Ag dopant and V o strengthen the O* adsorption with active sites, further promoting the deprotonation step from OH* to O* and accelerating the catalytic reaction. In a word, this work clarifies the structural correlation and synergistic mechanism of Ag dopant and V o , providing valuable insights for the rational design of catalyst for renewable energy applications. [ABSTRACT FROM AUTHOR]

Aliovalent substitution reduces the oxygen vacancy formation energy and generates more oxygen vacancies to facilitate the catalytic reaction. [Display omitted] Developing cost-effective monolith catalyst with superior low-temperature activity is critical for oxidative efficacious removal of industrial volatile organic compounds (VOCs). However, the complexity of the industrial flue gas conditions demands the need for high moisture tolerance, which is challenging. Herein, CoMn–Metal Organic Framework (CoMn–MOF) was in situ grown on Ni foam (NiF) at room temperature to synthesize the cost-effective monolith catalyst. The optimized catalyst, Co1Mn1/NiF, exhibited excellent performance in toluene oxidation (T 90 = 239 °C) due to the substitution of manganese into the cobalt lattice. This substitution weakened the Co–O bond strength, creating more oxygen vacancies and increasing the active oxygen species content. Additionally, experimentally and computationally evidence revealed that the mutual inhibiting effect of three typical aromatic hydrocarbons (benzene, toluene and m–xylene) over the Co1Mn1/NiF catalyst was attributed to the competitive adsorption occurring on the active site. Furthermore, the Co1Mn1/NiF catalyst also presents outstanding water resistance, particularly at a concentration of 3 vol%, where the activity is even enhanced. This was attributed to the lower water adsorption and dissociation energy derived from the interaction between the bimetals. Results demonstrate that the dissociation of water vapor enables more reactive oxygen species to participate in the reaction which reduces the formation of intermediates and facilitates the reaction. This investigation provides new insights into the preparation of oxygen vacancy–rich monolith catalysts with high water resistance for practical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Regulating interfacial active sites to improve peroxymonosulfate (PMS) activation efficiency is a hot topic in the heterogeneous catalysis field. In this study, we develop an inverted loading strategy to engineer asymmetric Mn–O V –Ce sites for PMS activation. Mn 3 O 4 @CeO 2 prepared by loading CeO 2 nanoparticles onto Mn 3 O 4 nanorods exhibits the highest catalytic activity and stability, which is due to the formation of more oxygen vacancies (O V) at the Mn–O V –Ce sites, and the surface CeO 2 layer effectively inhibits corrosion by preventing the loss of manganese ion active species into the solution. In situ characterizations and density functional theory (DFT) studies have revealed effective bimetallic redox cycles at asymmetric Mn–O V –Ce active sites, which promote surface charge transfer, enhance the adsorption reaction activity of active species toward pollutants, and favor PMS activation to generate (•OH, SO 4 •−, O 2 •− and 1O 2) active species. This study provides a brand-new perspective for engineering the interfacial behavior of PMS activation. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis and characterization of Ca 0.6 Sr 0.4-x Ba x ZrO 3 (x = 0.01, 0.04, 0.07, and 0.10) ceramics prepared via the solid-state method and sintered at 1450 °C. The impact of Sr substitution by Ba at the A-site of the perovskite structure on crystalline properties and microwave dielectric performance was investigated. The experimental results show the formation of a single-phase structure, Ca 0.612 Sr 0.388 ZrO 3 (CSZ), across the entire range of x values. It is evident that the Ca 0.6 Sr 0.39 Ba 0.01 ZrO 3 ceramics exhibits the highest sintering density and the lowest porosity. These ceramics exhibit impressive dielectric properties, including a high permittivity of 28.38, low dielectric loss of 4.0×10−4, and a Q factor value of 22988 at 9–10 GHz. The research reveals that the influences of Sr substitution by Ba in enhancing the microwave dielectric properties of Ca 0.612 Sr 0.388 ZrO 3 ceramics, and the impedance curves clearly showed effects on the electrical properties. [ABSTRACT FROM AUTHOR]

Dense Sm 2- x Ce x O 3+ x /2 (x = 0.10−0.25) ceramics were obtained by the solid-state method. Main-phase Sm 2 O 3 with monoclinic structure and a small amount of fluorite-structured CeO 2 were achieved. As the x value increased, the τ f significantly reduced from 18.8 ± 2.0 ppm/°C to −20.3 ± 2.0 ppm/°C and the Q × f enhanced from 21,382 ± 300–32,927 ± 300 GHz. The τ f variating from positive to negative was related to the increasing temperature coefficient of ion polarizability (τ αm) from 20.6 ppm/°C to 27.9 ppm/°C. The rise in Q × f was attributed to the reduced AC conductivity resulting from the decreasing oxygen vacancy concentration. The addition of Ce could effectively inhibit the decomposition of Sm 2 O 3 ceramics in atmospheric condition. Notably, the Sm 1.80 Ce 0.20 O 3.10 ceramic sintered at 1475 °C demonstrated optimal microwave dielectric properties of ε r = 19.2 ± 0.2, Q × f = 28,033 ± 300 GHz, and τ f = 1.8 ± 2.0 ppm/°C. [ABSTRACT FROM AUTHOR]

The particulate Pt/TiO2 catalyst was prepared by coprecipitation method for efficient catalytic combustion of toluene. The physicochemical properties of the as-prepared samples were explored by techniques including XRD, BET, XPS, and HRTEM. It was found that the reduction treatment not only introduced Ti3+ and a large amount of oxygen vacancies in the catalyst, but also produced Pt0. The catalytic activity is strongly affected by the synergistic effect of oxygen vacancies and platinum clusters within the sample, which also makes the catalyst's catalytic activity for toluene oxidation much higher than that of the unreduced catalyst. With respect to the catalytic decomposition of toluene, the Pt/TiO2 catalyst with proper oxygen vacancies shows excellent catalytic performance with 100% conversion under the conditions of 220°C, space velocity of 13 000 h–1. Even after 1800 min of continuous reaction at 250°C, the toluene removal rate is up to 100%. [ABSTRACT FROM AUTHOR]

A set of Cu/ZnO/ZrO2 catalysts doped with Group‐IIIA elements (M=B, Al, Ga & In) were synthesized via a facile single‐step evaporation‐induced self‐assembly (EISA) method to tune up the catalyst basicity and modulate the structure to improve the methanol yield in CO2 hydrogenation reaction. To understand the catalyst‘s textural properties and catalytic activity, prepared catalysts were exposed to several in‐situ/ex‐situ characterization techniques like Physisorption & Chemisorption studies, XRD, XPS, TEM, and in‐situ DRIFT. The addition of group IIIA elements has a significant impact on the CO2 conversion and Methanol selectivity via tailoring the important textural properties such as metallic surface area of Cu, reducibility of catalysts, particle size, controlled oxygen vacancy, and basicity of catalyst surface. CZZ doped with Al appeared to be the best catalyst, in this study. The modified Cu‐ZnO interface via density functional theory (DFT) calculations also indicated that the CO2 adsorption energy is found to be highest for CZZAl, which is concomitant with CO2‐TPD analysis results. The lowest to highest CO2 adsorption energy order over the catalyst set follows CZZIn

Anionic redox chemistry is now viewed as the effective paradigm of improving the capacity of layered oxide materials in Sodium‐ion battery. In this study, O3‐type layered oxide NaLi0.18Co0.23Ru0.59O2 (NLCR) with O redox ability is successfully synthesized via a facile solid‐state synthesis method. By manipulating the calcinate atmosphere with air and argon (sort by NLCR‐Air NLCR‐Ar respectively), a large amount of O vacancy is introduced in the NLCR‐Air cathode. NLCR‐Air with sufficient O vacancy exhibited superior rate performance which showed 87.7% capacity retention after 1000 cycles at 20 C. Both NLCR‐Air and NLCR‐Ar showed activation of O redox properties which is supported by the soft X‐ray absorption spectroscopy (sXAS). Nevertheless, the in‐situ X‐ray diffraction and sXAS studies disclosed the O vacancy can promote the reversible phase transition and effectively suppress the irreversible O redox upon cycling. These are further supported by theoretical study which suggested a fast kinetic of Na diffusion and less electron agglomeration around the O atom for NLCR‐Air with O vacancy.The research proposed a modification strategy with extraordinary reversible O redox property within O3‐type layered cathode and offered a novel insight into understanding the anionic redox mechanism thus provide guidance of material design advanced energy storage systems. [ABSTRACT FROM AUTHOR]

Regulating the bandgap edge and building oxygen vacancy (OV) engineering are effective countermeasures for facilitating interfacial charge carrier transfer/separation. Herein, bandgap-matched 2D g-C3N4/WO3–xZ-scheme heterojunction nanocomposites were fabricated using the pyrolysis method with bulk g-C3N4 and WO3 nanorods. Meanwhile, the bandgap edge of g-C3N4 is being fine-tuned, while the OVs in WO3 are deliberately engineered. Satisfactory results were achieved, wherein the photodegraded MO by the 2D g-C3N4/20.0 wt % WO3–xZ-scheme heterojunction nanocomposite was 6.36, 3.78, and 11.07 times higher than that of bulk g-C3N4, 2D g-C3N4, and WO3–x, respectively. Additionally, the photoreduction of Cr (VI) of the former was 8.92, 5.23, and 14.76 times higher than that of the latter three, respectively. There are two primary reasons for the notable increase in the photocatalytic rate: first, through secondary pyrolysis, g-C3N4 can attain a bandgap structure that matches the bandgap of WO3; second, WO3 can generate chippy OV active centers. Furthermore, the synergistic interaction between the two components generates additional interface charges and promotes increased photon absorption, ultimately enhancing the photocatalytic rate. This study offers insights into designing and constructing g-C3N4Z-scheme heterojunction nanocomposites through bandgap and OV engineering for visible-light-driven wastewater purification. [ABSTRACT FROM AUTHOR]

Bismuth ferrite (BiFeO3)‐based high‐temperature piezoelectric ceramics have high Curie temperatures and excellent thermal stability; however, their applications are limited by inadequate piezoelectric performance due to large coercive fields and high leakage conduction. This study investigates the impact of MnO2 doping on the phase transition, defect structure, domain morphology, as well as the dielectric, ferroelectric, and electrical conduction behaviors of 75BiFeO3–25BaTiO3 ceramics sintered under an oxygen atmosphere. A structural transformation from distorted rhombohedral to pseudo‐cubic symmetry was observed with increasing MnO2 content, accompanied by domain fragmentation. MnO2 doping at an appropriate level inhibited defects such as Fe′Fe$\ {\mathrm{F}}{{{\mathrm{e^{\prime}}}}_{{\mathrm{Fe}}}}$ and VO2−⋅⋅$V_{{{{\mathrm{O}}}^{{\mathrm{2}} - }}}^{\centerdot \centerdot }$. Regarding electrical properties, the reduction in rhombohedral distortion and enhancement in the pseudo‐cubic phase after MnO2 doping resulted in decreased remanent polarization and electrostrain, which could potentially hinder piezoelectric response. However, appropriate MnO2 doping effectively reduced leakage conduction, significantly enhancing the poling efficiency of the ceramics. The maximum d33 value of 107 pC/N and kp of 0.36 were achieved at an MnO2 doping content of 0.1 wt.%. Excessive MnO2 addition may generate 2Mn′Ti−VO2−⋅⋅${\mathrm{2M}}{{{\mathrm{n^{\prime}}}}_{{\mathrm{Ti}}}}-V_{{{{\mathrm{O}}}^{{\mathrm{2}} - }}}^{\centerdot \centerdot }$ defect dipoles, as indicated by increased coercive field (Ec) and dielectric loss. The observed increase in high‐temperature resistivity with MnO2 content is primarily attributed to reduced grain size and increased concentration of mobile defects. This study provides valuable insights for further research on the application of 75BiFeO3–25BaTiO3 systems in high‐temperature piezoelectric devices. [ABSTRACT FROM AUTHOR]

Using piezoelectric bionanomaterials to promote the generation of reactive oxygen species (ROS) is being increasingly recognized in ultrasound (US)‐triggered tumor treatments. The mechanism underlying this innovative treatment involves US irradiation, which activates the built‐in electric field (BIEF) and induces energy‐band bending in piezoelectric materials (PEMs). In this study, Sr0.5Ba0.5Nb2O6 (SBN) nanorods (NRs) are synthesized using a molten salt method. Subsequently, oxygen‐vacancy (OV)‐rich SBN/Sr2Nb2O7 (SBN/SNO) heterojunction nanocomposites (NCs) are fabricated via H2 annealing of the SBN NRs. The engineering strategy focused on enhancing ROS generation, thereby augmenting the piezoelectric catalytic activity of the NCs. This configuration ensures that the BIEF and heterojunction‐induced field act synergistically to provide a sustained driving force for the separation of electron‐hole (e−‐h+) pairs. Importantly, the OVs on the surfaces of the H2‐annealed SBN NRs create electron‐rich sites, which substantially enhance their piezocatalytic capabilities. In vitro and in vivo analyses of hepatocellular carcinoma (HCC) models demonstrate the significant cytotoxic and tumor‐inhibitory capabilities of this rich OV‐mediated sonopiezoelectric therapy (SPT) and illustrate its potential as a promising therapeutic approach against cancer. [ABSTRACT FROM AUTHOR]

Cation-disordered rocksalt (DRX) oxides show promise as lithium-ion battery cathodes due to their high theoretical capacity derived from anionic redox. However, the challenges of poor anionic redox reversibility, causing oxygen loss and voltage hysteresis, lead to rapid capacity decay. This study employs a dual-functional urea treatment on Li1.2Ti0.4Mn0.4O2 DRX cathodes, generating oxygen vacancies in the subsurface and a protective carbon nitride layer on the surface through interface reactions. Characterization via X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy confirms these alterations. The presence of oxygen vacancies reduces the average Mn valence, increasing the capacity contributed by Mn and enhancing the reversibility of anionic oxygen redox, thus curbing oxygen loss. Additionally, the carbon nitride layer curtails the parasitic reaction between active oxygen species and the electrolyte. Urea-treated Li1.2Ti0.4Mn0.4O2 exhibits enhanced electrochemical performance, retaining a higher capacity (151 mAh⋅g−1, 80.3% of capacity retention) after 50 cycles compared to neat Li1.2Ti0.4Mn0.4O2 (117 mAh⋅g−1, 64.6% retention). Furthermore, the treatment improves lithium-ion diffusion and rate capability. This dual-functional urea approach presents a promising strategy for enhancing DRX cathode materials and advancing high-performance lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Improving the oxygen diffusion capacity of solid electrolyte material is an important goal of researchers in recent decades. For this purpose, the blackening of zirconia was considered as a new strategy to enhance its oxygen diffusion capacity. We comparatively investigated the oxygen transport properties of white (YSZ, yttria stabilized zirconia) and black (ZSZ, Zr3+ stabilized zirconia) zirconia by molecular dynamics simulation. The simulation results show that the ZSZ has the same oxygen diffusion mechanism as YSZ. Furthermore, the ZSZ has a much better oxygen diffusion capacity than YSZ, which is confirmed by the lower minimum oxygen diffusion activation energy of ZSZ (0.37 eV) than that of YSZ (0.46 eV). The different oxygen diffusion capacity between YSZ and ZSZ is attributed to their crystal structure difference. The Zr3+ ionic radius is much closer to that of Zr4+ than that of Y3+, and it induces smaller lattice distortion in stabilized zirconia to impose a minimal steric blocking effect on the oxygen diffusion process. Therefore, the Zr3+ is preferred over Y3+to enhance the oxygen diffusion capacity of stabilized zirconia and the black YSZ co-doped by Y3+ and Zr3+ is proven to be a promising solid electrolyte material with a better oxygen diffusion capacity than YSZ. [ABSTRACT FROM AUTHOR]

Hydrogen generation via photoelectrochemical (PEC) overall water splitting is an attractive means of renewable energy production so developing and designing the cost-effective and high-activity bifunctional PEC catalysts both for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) has been focused on. Based on first-principles calculations, we propose a feasible strategy to enhance either HER or OER performance in the monoclinic exposed BiVO4 (110) facet by the introduction of oxygen vacancies (Ovacs). Our results show that oxygen vacancies induce charge rearrangements, which enhances charge transfer between active sites and adatoms. Furthermore, the incorporation of oxygen vacancies reduces the work function of the system, which makes charge transfer from the inner to the surface more easily; thus, the charges possess stronger redox capacity. As a result, the Ovac reduces both the hydrogen adsorption-free energy (ΔGH*) for the HER and the overpotential for the OER, facilitating the PEC activity of overall water splitting. The findings provide not only a method to develop bifunctional PEC catalysts based on BiVO4 but also insight into the mechanism of enhanced catalytic performance. [ABSTRACT FROM AUTHOR]

In the dry reforming of methane (DRM), metal doping is used as one of the important methods to modulate the catalyst performance. In this paper, we synthesized two types of catalysts, Rh doped TiO2 (RTO) and Rh/Nb co-doped TiO2 (RNTO), and evaluated their performances in DRM. The CH4 and CO2 conversion of 79% and 95% in RTO were both higher than that in RNTO (the CH4 and CO2 conversion of 73% and 87%) as working for 80 h. The characterizations of XRD, TEM, XPS, EPR, BET, and TPR were carried out to determine the structure of catalysts. We found that the creation of the oxygen vacancies is favorable in Rh solely doped TiO2 but restricted by Rh/Nb co-doping. The XPS results verified that Rh4+ and Rh3+ were presented in RTO, while only Rh3+ can be observed in RNTO. Due to the co-doping of Nb, the Rh induced charge perturbation was balanced by Nb5+ rather than the deprivation of electrons from O2−, therefore the state of Rh3+ was stabilized and the content of oxygen vacancies were decreased which resulted in attenuated activity in the DRM reaction. [ABSTRACT FROM AUTHOR]

Sr 0.99 La 0.01 TiO 3 (SLT10) colossal permittivity (CP) ceramic materials were synthesized using solid phase method and secondary heat treated using mixed oxidant 35%Bi 2 O 3 –10%Al 2 O 3 –20%MgO–25%CuO–10%SiO 2 oxidant. The heat treatment atmospheres were chosen as O 2 , air, and Ar to correspond to different oxygen partial pressures. The dielectric properties of the Sr 0.99 La 0.01 TiO 3 -Percolated (SLT10-P) ceramics were investigated, and the contribution of the oxidant to the resistivity enhancement was verified by complex impedance spectroscopy and DC resistivity tests. Excellent dielectric properties were obtained for SLT10-P Air ceramic sample (16543 for dielectric permittivity and 0.016 for loss tangent), and the resistivity was increased from 2.13 × 108 Ω cm (SLT10) to 1.23 × 1011 Ω cm (SLT10-P Air). The resistance degradation mechanism of SLT10-P ceramics and oxygen vacancy migration in the process of resistance degradation were studied by using resistance monitoring device and thermally stimulated depolarization currents (TSDC) test. The introduction of oxidant optimizes the temperature stability and resistivity of SLT10 ceramics, but it will lead to the decrease of dielectric permittivity. The atmosphere of heat treatment changed the concentration of oxygen vacancy in ceramics. When SLT10-P O 2 was treated in O 2 atmosphere, the concentration of oxygen vacancy in ceramics decreased, which led to the decrease of dielectric permittivity and the increase of grain boundary resistance. For SLT10-P Ar ceramic, more oxygen vacancies and free electrons are induced by low oxygen partial pressure heat treatment, which enhances the dipole effect of electron pinning defects and leads to colossal dielectric permittivity, but high concentration of oxygen vacancies will affect the resistance decline. In SLT10-P Air ceramic, the coexistence of colossal permittivity and low loss tangent and high resistance is realized. [ABSTRACT FROM AUTHOR]

The presence of by-product water produced during the CO2 hydrogenation to methanol reaction will accelerate the aggregation and sintering of CuZn species, resulting in serious deactivation of the catalyst. CeO2 has weak hydrophilicity and high hydrothermal stability, which can enhance the dispersion of CuZn species. Consequently, a series of CuZn-based catalysts with controllable crystal planes of CeO2 carriers were synthesized by hydrothermal method, and appropriate concentrations of oxygen vacancy were strategically introduced. The physicochemical properties such as morphologies and structures and reduction performances of the synthesized CeO2 carriers and CuZn/CeO2-y catalysts (y represents rod, cube or otca) were studied by characterization methods such as TEM, XRD and H2-TPR. The catalytic performances of CuZn/CeO2-y catalysts in CO2 hydrogenation to methanol were also investigated. The results show that the CeO2 carrier with nanorod structure and exposed (110) crystal plane (CeO2-rod) is more conducive to the dispersion of CuZn-based species. Moreover, CeO2-rod and Cu species form Cu--O--Ce interface, which enhances the ability of the catalyst to adsorb and activate CO2 and H2 simultaneously. Therefore, CuZn/CeO2-rod catalyst exhibits high CO2 conversion and methanol selectivity. Under the conditions of 260 °C and 3 MPa, the space-time yield of methanol is up to 433.4 g/(kg⋅h), and methanol selectivity is up to 68.5%. Simultaneously, the reaction paths and evolution of intermediates in CO2 hydrogenation to methanol were thoroughly delineated by in situ diffuse reflectance infrared Fourier transform spectroscopy. It is found that under the action of CuZn/CeO2 catalysts, the reaction mainly follow the formate path. The crystal plane effect of the carrier does not change the reaction paths, but it increases the equilibrium rate of important intermediate species. [ABSTRACT FROM AUTHOR]

Rational design of highly active catalysts for breaking hydrogen-oxygen bonds is of great significance in energy chemical reactions involving water. Herein, an efficient strategy for the artificial atom (RuPd) established by d-orbital coupling and adjusted by oxygen vacancy (VO) is verified for water dissociation. As an experimental verification, the turnover frequency of RuPd-TiO2-VO (RuPdTVO) catalyst in ammonia borane hydrolysis reaches up to 2750 min−1 (26,190 min−1 based on metal dispersion) in the absence of alkali, exceeding the highest active catalysts (Rh-based catalysts). The d-orbital coupling effect between Ru and Pd simulates the outer electronic structure of Rh. Electron transfer from VO to (RuPd) constructs an electron-rich state of active sites that further enhances the ability of the artificial atom to dissociate water. This work provides an effective electronic regulation strategy from VO and artificial atom constructed by d-orbital coupling effect for efficient water dissociation. [ABSTRACT FROM AUTHOR]

The role of dopants (Sm, Tb and Pr) on the water–gas shift performance of CeO2-based materials was studied. Modification of CeO2 with Sm significantly improved the water–gas shift performance. The catalytic activities of doped CeO2 were increased when compared with the catalytic activities of pure ceria (65% conversion at 600 °C for Ce5%SmO and 50% conversion at 600 °C for CeO2). The key factors driving the water–gas shift performance were reduction behavior and oxygen vacancy concentration. In the redox mechanism of the WGS reaction, CeO2 plays a crucial role in transferring oxygen to CO through changes in the oxidation state. Therefore, Sm is effective in catalyzing the water–gas shift activity because the addition of Sm into CeO2 decreases the surface reduction temperature and alters the oxygen transportation ability through the redox mechanism. XRD results suggested that Mn+ (M = Sm, Tb and Pr) incorporate into ceria lattice to form a solid solution resulting in unit cell enlargement. The defect structure inside the CeO2 lattice generates a strain on the oxide lattice and facilitates the generation of oxygen vacancies. XANES analysis revealed that Sm reduced CeO2 easily by transporting its electron into the d-orbitals of Ce, thus giving rise to more Ce3+ at the CeO2 surface. The presence of Ce3+ is a result of oxygen vacancy. Therefore, the high content of Ce3+ provides more oxygen vacancies. The oxygen vacancy formation results in easy oxygen exchange. Thus, reactive oxygen species can be generated and easily reduced by CO reactant, which enhances the WGS activity. [ABSTRACT FROM AUTHOR]

As an emerging secondary battery system, aqueous zinc-ion batteries (AZIBs) show a broad application prospect in the fields of large-scale energy storage and wearable devices. Manganese-based cathode materials have been widely investigated by many researchers due to their high natural abundance, low toxicity, and multiple variable valence states. However, limited active sites, insufficient solvation, and reactivity kinetics of Mn2+ lead to the attenuation of their electrochemical performance. Herein, we introduce appropriate oxygen vacancies into the δ-MnO2 structure by modulating the annealing temperature. The obtained δ-MnO2-400 electrode provided 503 mAh/g capacity at 0.2 A/g and 99% capacity retention after 3000 times cycling at 1 A/g. [ABSTRACT FROM AUTHOR]

Improving the efficiency of metal/reducible metal oxide interfacial sites for hydrogenation reactions of unsaturated groups (e.g., C=C and C=O) is a promising yet challenging endeavor. In our study, we developed a Pd/CeO2 catalyst by enhancing the oxygen vacancy (OV) concentration in CeO2 through high-temperature treatment. This process led to the formation of an interface structure ideal for supporting the hydrogenation of methyl oleate to methyl stearate. Specifically, metal Pd0 atoms bonded to the OV in defective CeO2 formed Pd0–OV–Ce3+ interfacial sites, enabling strong electron transfer from CeO2 to Pd. The interfacial sites exhibit a synergistic adsorption effect on the reaction substrate. Pd0 sites promote the adsorption and activation of C=C bonds, while OV preferably adsorbs C=O bonds, mitigating competition with C=C bonds for Pd0 adsorption sites. This synergy ensures rapid C=C bond activation and accelerates the attack of active H* species on the semi-hydrogenated intermediate. As a result, our Pd/CeO2-500 catalyst, enriched with Pd0–OV–Ce3+ interfacial sites, demonstrated excellent hydrogenation activity at just 30 °C. The catalyst achieved a Cis–C18:1 conversion rate of 99.8% and a methyl stearate formation rate of 5.7 mol/(h·gmetal). This work revealed the interfacial sites for enhanced hydrogenation reactions and provided ideas for designing highly active hydrogenation catalysts. [ABSTRACT FROM AUTHOR]

Recent research has focused a great deal of emphasis on multifunctional soft ferromagnetic (FM) materials based on perovskite-type structures, as these materials are in great demand for spintronic applications. In this work, wet sol–gel synthesis was used to produce BaTi1−xMnxO3 nanoparticles doped with two different concentrations of Mn at a cheap cost. The x-ray diffraction (XRD) data indicate that Mn doping marginally increases the lattice parameters of BaTiO3, but nevertheless maintains the tetragonal phase of the material. The study of the doped nanoparticles using transmission electron microscopy (TEM) shows that they are aggregated with a polycrystalline structure. For 0.25% and 0.5% Mn-doped BaTiO3, the computed grain size distribution had average diameters of 47.20 ± 1.05 and 60.97 ± 0.87 nm, respectively. An investigation using x-ray photoelectron spectroscopy (XPS) revealed that the nanoparticles' faulty oxygen concentration increased due to Mn doping. UV–vis measurements indicate that the band gap slightly decreases from 2.28 eV to 2.25 eV, whereas the photoluminescence emission intensity is found to be decreasing with Mn content in BaTiO3. Magnetic measurements reveal that the 0.5%Mn-doped BaTiO3 material specifically exhibits soft FM features with its small coercivity (HC = 97 Oe) and low saturation magnetization (MS = 0.025 emu/g), that suggest its viability for developing spintronic applications, particularly for minimizing device energy consumption. [ABSTRACT FROM AUTHOR]

The adsorbate‐mediated strong metal‐support interaction (A‐SMSI) offers a reversible means of altering the selectivity of supported metal catalysts, thereby providing a powerful tool for facile modulation of catalytic performance. However, the fundamental understanding of A‐SMSI remains inadequate and methods for tuning A‐SMSI are still in their nascent stages, impeding its stabilization under reaction conditions. Here, we report that the initial concentration of oxygen vacancy in oxide supports plays a key role in tuning the A‐SMSI between Ru nanoparticles and defected titania (TiO2‐x). Based on this new understanding, we demonstrate the in situ formation of A‐SMSI under reaction conditions, obviating the typically required CO2‐rich pretreatment. The as‐formed A‐SMSI layer exhibits remarkable stability at various temperatures, enabling excellent activity, selectivity and long‐term stability in catalyzing the reverse water gas‐shift reaction. This study deepens the understanding of the A‐SMSI and the ability to stabilize A‐SMSI under reaction conditions represents a key step for practical catalytic applications. [ABSTRACT FROM AUTHOR]

The adsorbate‐mediated strong metal‐support interaction (A‐SMSI) offers a reversible means of altering the selectivity of supported metal catalysts, thereby providing a powerful tool for facile modulation of catalytic performance. However, the fundamental understanding of A‐SMSI remains inadequate and methods for tuning A‐SMSI are still in their nascent stages, impeding its stabilization under reaction conditions. Here, we report that the initial concentration of oxygen vacancy in oxide supports plays a key role in tuning the A‐SMSI between Ru nanoparticles and defected titania (TiO2‐x). Based on this new understanding, we demonstrate the in situ formation of A‐SMSI under reaction conditions, obviating the typically required CO2‐rich pretreatment. The as‐formed A‐SMSI layer exhibits remarkable stability at various temperatures, enabling excellent activity, selectivity and long‐term stability in catalyzing the reverse water gas‐shift reaction. This study deepens the understanding of the A‐SMSI and the ability to stabilize A‐SMSI under reaction conditions represents a key step for practical catalytic applications. [ABSTRACT FROM AUTHOR]

We, at the ab initio level, simulated the rearrangement magnitudes of the adjacent neighboring ions, surrounding the (100) surface F-center in ABO3 perovskite matrixes. They are noticeably greater than the respective ionic shift magnitudes of the adjacent neighboring ions surrounding the bulk F-center. In ABO3 perovskites, the electron charge is noticeably better bounded on the inside of the bulk oxygen vacancy, as interior the respective (100) surface vacancy. The oxygen vacancy formation energy, located on the (100) surface of ABO3 perovskites, as a rule, is smaller as in the bulk. This slight energy distinction encourages the oxygen vacancy segregation from the ABO3 perovskite bulk to their (100) surfaces. The ABO3 complex oxide (100) surface F-center generated defect levels are positioned nearer to the (100) surface CB bottom than the bulk F-center generated respective defect levels. In contrary, the BaF2, SrF2 and CaF2, both, surface and bulk F-center charges are well localized inside the fluorine vacancy. The ionic rearrangement magnitudes of the adjacent neighboring ions, surrounding the surface and bulk F-centers in BaF2, SrF2 and CaF2 matrixes, are much smaller regarding the respective situation in ABO3 perovskites. [ABSTRACT FROM AUTHOR]

The adsorbate‐mediated strong metal‐support interaction (A‐SMSI) offers a reversible means of altering the selectivity of supported metal catalysts, thereby providing a powerful tool for facile modulation of catalytic performance. However, the fundamental understanding of A‐SMSI remains inadequate and methods for tuning A‐SMSI are still in their nascent stages, impeding its stabilization under reaction conditions. Here, we report that the initial concentration of oxygen vacancy in oxide supports plays a key role in tuning the A‐SMSI between Ru nanoparticles and defected titania (TiO2‐x). Based on this new understanding, we demonstrate the in situ formation of A‐SMSI under reaction conditions, obviating the typically required CO2‐rich pretreatment. The as‐formed A‐SMSI layer exhibits remarkable stability at various temperatures, enabling excellent activity, selectivity and long‐term stability in catalyzing the reverse water gas‐shift reaction. This study deepens the understanding of the A‐SMSI and the ability to stabilize A‐SMSI under reaction conditions represents a key step for practical catalytic applications. [ABSTRACT FROM AUTHOR]

The adsorbate‐mediated strong metal‐support interaction (A‐SMSI) offers a reversible means of altering the selectivity of supported metal catalysts, thereby providing a powerful tool for facile modulation of catalytic performance. However, the fundamental understanding of A‐SMSI remains inadequate and methods for tuning A‐SMSI are still in their nascent stages, impeding its stabilization under reaction conditions. Here, we report that the initial concentration of oxygen vacancy in oxide supports plays a key role in tuning the A‐SMSI between Ru nanoparticles and defected titania (TiO2‐x). Based on this new understanding, we demonstrate the in situ formation of A‐SMSI under reaction conditions, obviating the typically required CO2‐rich pretreatment. The as‐formed A‐SMSI layer exhibits remarkable stability at various temperatures, enabling excellent activity, selectivity and long‐term stability in catalyzing the reverse water gas‐shift reaction. This study deepens the understanding of the A‐SMSI and the ability to stabilize A‐SMSI under reaction conditions represents a key step for practical catalytic applications. [ABSTRACT FROM AUTHOR]

Oxygen vacancy (OV) states are the most prevalent chemical defects in metal oxides without extrinsic dopants, which govern the regime of photoelectrochemical (PEC) kinetics. So far, although tremendous strategies are developed to overcome the negative effects from OV, the threshold at which OV plays a positive role has not been specifically studied. Furthermore, the kinetics of stoichiometry changes as well as their effects on the charge transport aroused from manipulating OV distribution are still in confusion. Here, taking α-Ga2O3 nanorod arrays as the model, we show the evolution mechanism about the changes in OV distribution during vacancy engineering. Since the O diffusion flow into bulk is regulated by the surface OV-assisted migration mechanism, the surface OV concentration decreased first and recovered slightly after a period of time. This is deviated from the common sense that the longtime O2 annealing should bring about monotonical OV decrease at the surface. After PEC characterization and theory calculation, the results show that OV plays to the score in the PEC process, depending on its own spatial distribution. The optimized engineering strategy of OV spatial distribution is proposed to establish the efficient carrier separation nanoarchitectures for high-performance UV photodetection. This work provides an insight for clarifying fundamental rules for defect engineering in the PEC field. [ABSTRACT FROM AUTHOR]

Converting carbon dioxide into valuable chemicals requires suitable catalysts to perform efficiently under severe reaction conditions. Developing suitable supported copper catalysts can potentially improve catalytic performance for CO 2 reduction by interacting with copper active components. Herein, we investigate Cu/ZrO 2 catalysts, synthesized by wet-impregnation (WI) method with various copper contents, for the reverse water-gas shift (RWGS) reaction. It is anticipated that metal-support interaction, surface defects, and oxygen vacancies in oxide catalysts play critical roles in defining catalytic activity. To understand this, various ZrO 2 -supported catalysts with different crystallite sizes were prepared by altering the calcination temperature and assessing their catalytic performance. The results showed that 2 wt%Cu/ZrO 2 catalyst calcined at 800 °C had the highest CO 2 conversion to CO of ∼37 % at 600 °C, with less than 0.25 % coke formation. Kinetics studies showed that the redox model agreed better with experimental data when considering equilibrium conditions. [Display omitted] • Volcano correlations in CO 2 conversion curves with peaks at 2 wt%Cu and 800 °C. • Better reducibility, high dispersion, and stronger MSI in 2 wt%Cu/ZrO 2 -800 sample. • ZrO 2 phase change from monoclinic to tetragonal by raising calcination temperature. • 37 % conversion at 600 °C with 2 wt%Cu/ZrO 2 -800 catalyst, stable for 72 h TOS. • Redox mechanism of the 2 wt%Cu/ZrO 2 -800 catalyst in RWGS, based on kinetic studies. [ABSTRACT FROM AUTHOR]

Molybdenum trioxide (MoO3) is an attractive semiconductor. Thus, bandgap engineering toward photoelectronic applications is appealing yet not well studied. Here, we report the incorporation of sulfur atoms into MoO3, using sulfur powder as a source of sulfur, via a self-developed hydrothermal synthesis approach. The formation of Mo-S bonds in the MoO3 material with the synergistic effect of sulfur doping and oxygen vacancies (designated as S-MoO3−x) is confirmed using Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR). The bandgap is tuned from 2.68 eV to 2.57 eV upon sulfur doping, as confirmed by UV-VIS DRS spectra. Some MoS2 phase is identified with sulfur doping by referring to the photoluminescence (PL) spectra and electrochemical impedance spectroscopy (EIS), allowing significantly improved charge carrier separation and electron transfer efficiency. Therefore, the as-prepared S-MoO3−x delivers a sensitive photocurrent response and splendid cycling stability. This study on the synergistic effect of sulfur doping and oxygen vacancies provides key insights into the impact of doping strategies on MoO3 performance, paving new pathways for its optimization and development in relevant fields. [ABSTRACT FROM AUTHOR]

Metal halide perovskite semiconductors have demonstrated remarkable performance in light‐emitting‐diode applications in recent years. However, their potential application in other emerging optoelectronic devices, such as light‐emitting field‐effect transistors (LEFETs) is impeded by poor luminous efficiency due to inefficient charge injection. Here, an n‐type MgZnInO (MIZO) as the channel layer is synthesized to achieve efficient electron injection in perovskite LEFETs. These findings indicate that the incorporation of Mg not only suppresses the generation of oxygen vacancies but also optimizes the energy level alignment. These synergistic effects reduce non‐radiative recombination and improve interfacial charge transport. Consequently, the MIZO‐based perovskite LEFETs exhibit an improvement in threshold voltage, subthreshold swing, and field‐effect mobility. The electroluminescence performance shows a peak external quantum efficiency (EQE) of 1.97% with a maximum brightness of 2.1 × 104 cd m−2, accompanied by low‐efficiency roll‐off (an EQE of 1.88% at the current density of 810 mA cm−2). To the best of the author's knowledge, this represents the best luminous efficiency reported for perovskite LEFETs to date. [ABSTRACT FROM AUTHOR]

[Display omitted] The generation of hydrogen as a clean energy carrier by photocatalysis, as a zero-emission technology, is of significant scientific and industrial interest. However, the main drawback of photocatalytic hydrogen generation from water splitting is its low efficiency compared to traditional chemical or electrochemical methods. Zinc oxide (ZnO) with the wurtzite phase is one of the most investigated photocatalysts for hydrogen production, but its activity still needs to be improved. In this study, an oxygen-deficient high-pressure ZnO rocksalt phase is stabilized using a high-pressure torsion (HPT) method, and the product is used for photocatalysis under ambient pressure. The simultaneous introduction of oxygen vacancies and the rocksalt phase effectively improved photocatalytic hydrogen production to levels comparable to benchmark P25 TiO 2 , due to improving light absorbance and providing active sites for photocatalysis without any negative effect on electron-hole recombination. These results confirm the high potential of high-pressure phases for photocatalytic hydrogen generation. [ABSTRACT FROM AUTHOR]

In the work, a high-performance Eu 2 Sn 2 O 7 –SnO 2 (ES-2) humidity sensors were prepared through a one-step hydrothermal method. Eu 2 Sn 2 O 7 is a bimetallic material can increase the adsorption capacity to water molecules and promote electron transfer, thus improving the sensitivity of the sensor. The introduction of Eu 2 Sn 2 O 7 promotes the increase of the content of oxygen vacancies in the ES-2 composite material, which promotes the accelerated decomposition of water molecules, and facilitates the formation of the chemisorbed layer to improve the sensitivity of the sensor and the response time. The increase in specific surface area of ES-2 provided more adsorption sites for H 2 O and also provided a good transport channel for water molecules to diffuse into the interior of the material. ES-2 humidity sensor exhibits high sensitivity (22,405 ± 363), small humidity hysteresis (1 ± 0.3 %), short response/recovery time (7/6 ± 0.5 s), good repeatability and stability (11%–95 % RH). This study not only promotes the development of SnO 2 -based humidity sensors, but provides new ideas for the preparation of high-performance humidity sensors. [ABSTRACT FROM AUTHOR]

Memristors, recognized as key devices for mitigating the von Neumann bottleneck, show great potential in non-volatile memory technology. Their performance is fundamentally linked to the chemical composition and structural characteristics of their intermediate dielectric layer. Owing to the inherent advantages of metal oxides, such as their simplistic chemical makeup and superior thermal stability, memristors featuring a Metal-Insulator-Metal (MIM) sandwich structure with metal oxides as the intermediate layer have received extensive focus. In this study, a Pt/Ni 0.5 Zn 0.5 Mn x Fe 2-x O 4 (NZMFO)/Pt composite film was prepared, and its resistance switching behavior was modulated by altering the doping concentration of Mnn+ in NZMFO. The experimental results indicate that altering the Mnn+ doping concentration does significantly impact the content of oxygen vacancies. As the concentration of Mnn+ increases from 0.10 to 0.20 at.%, the content of oxygen vacancies correspondingly rises from 46.58 % to 76.42 %. Concurrently, variations in Mnn+ doping concentration significantly alter the resistance switching properties of the Pt/NZMFO/Pt composite films. This includes elevating the set/reset voltage, diminishing the resistance ratio, and enhancing the durability with the augmentation of Mnn+ concentration. By meticulously adjusting the Mnn+ doping concentration, we can achieve a memristor characterized by superior performance across all metrics. Considering all performance aspects, this study determined that the Pt/NZMFO/Pt thin film memristor with x = 0.15 exhibits adequate endurance (100 cycles), high data retention, and stable set/reset voltage. This work underscores the critical role of Mnn+ doping concentration in optimizing the electrochemical properties of NZFO memristors, illustrating a strategic pathway to engineer memristive devices with enhanced performance for future non-volatile memory applications. [ABSTRACT FROM AUTHOR]

The application of BiVO4 in photoelectrochemical water splitting for efficient clean hydrogen energy production encounters challenges arising from the sluggish kinetics of water oxidation. Motivated by the synergistic interplay of metal sites and ligands on the catalyst surface, we utilized the photoelectric deposition technique to introduce amorphous nanothin layers of cobalt–iron double hydroxide (referred to as CoFe-LDH) onto the Fe-doped BiVO4 surface. Fe dopants lead to a size reduction of BiVO4 nanoparticles while enlarging the specific surface area and pore volume, thus increasing the reaction sites, which is favorable for photoelectrochemical water splitting. The unique dual-layered structure of CoFe-LDH not only enhances the mobility of charge carriers but also addresses surface defects through passivation. Additionally, it optimizes the exposure of active sites on the surface and expedites the flow of charge carriers, effectively mitigating recombination. The CoFe/Fe-BiVO4 photoanode demonstrates outstanding photocatalytic performance, achieving a substantial photocurrent of 2.56 mA cm–2 (at 1.23 V vs RHE) and an impressive incident photon current conversion efficiency (IPCE) of 52.1% at 400 nm, which is approximately a 270% increment in photocurrent and a remarkable 2.2-fold improvement in IPCE compared to those of the unmodified sample. In addition, the charge surface transport efficiency increases from 16.8% to 62.5% at 1.23 V vs RHE after modification of the cobalt–iron hydroxide bilayer. This study not only emphasizes the promising results of employing binary polymetallic co-catalysts but also provides a strategic pathway to improve semiconductor-based photoelectrodes in various photoelectrochemical applications. [ABSTRACT FROM AUTHOR]