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ABX3 (X = O) perovskite oxides are an uprising class of alternative electrocatalysts in eminent technologies like electrocatalysis, photocatalysis, thermocatalysis, and energy storage. The perquisites of perovskite oxide catalysts encompass ordered atomic structure, structural/compositional extensibility, flexible electronic structure, lucrativeness, and so on. The ingenuity to precisely control and tune the inherent properties by reconstructing their crystal structure is particularly advantageous in electrocatalysis reactions like oxygen reduction and evolution reactions (ORR and OER). Incorporating multidimensional imperfections in the presumably perfect crystal structure of the perovskite catalysts is garnering booming attention among researchers. This concept can expertly influence the electronic structure and boost the reaction kinetics during electrocatalysis. Defects or imperfections are achieved by substituting A‐ and/or B‐sites with heteroatoms or by oxygen vacancies. Defect engineering points to a promising new direction in the development of perovskite oxide catalysts. This work surveys the recent progress in defect engineering and how it plays a vital role in their design, and application in electrocatalysis, mainly ORR/OER. The architecture, dimensionality, and the types of perovskite oxides based on their cations, crystal structures, and stoichiometries are surveyed for a comprehensive understanding. This review aims to provide an extensive outlook on oxide perovskite catalysts concerning structural defects. [ABSTRACT FROM AUTHOR]

An innovative plasma-treated strategy was employed to prepare La x Ce 1-x MnO 3 (LCMO) perovskite oxides. Pd nanoparticles were loaded onto plasma-treated (P) and air-calcined (T) LCMO respectively, forming the corresponding Pd/LCMO catalysts. The results indicated that the introduction of Pd and plasma treatment largely boost the catalytic activity in methane combustion. Among these catalysts, the Pd/LCMO-P catalyst shows the best performance in CH 4 oxidation, giving T 90 of 425 °C. It was revealed that the morphology structure and surface defects were strongly affected by plasma treatment, further affecting the dispersion and chemical state of Pd species via surface interaction. The superior performance should be ascribed to the good redox properties (high Mn4+/Mn3+ ratio), rich surface-active oxygen species, and enhanced oxygen mobility (weakened Pd-O and Mn-O chemical bonds). Besides, the distributions of cerium in the surface and crystal lattice of LMO also improved metal-support interaction and the oxygen mobility, that boosted CH 4 oxidation. This plasma-treated strategy provided an effective path to develop the efficient combustion catalyst for superior performance. [ABSTRACT FROM AUTHOR]

Orthorhombic perovskite GdFeO3 nanostructures are promising materials with multiferroic properties. In this study, a new low‐temperature plasma‐assisted approach is developed via dual anodic dissolution of solid metallic precursors for the preparation of perovskite GdFeO3 nanoparticles (NPs) that can be collected both as colloids as well as deposited as a thin film on a substrate. Two solid metallic foils of Gd and Fe are used as precursors, adding to the simplicity and sustainability of the method. The formation of the orthorhombic perovskite GdFeO3 phase is supported by high‐resolution transmission electron microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, and Raman measurements, while a uniform elemental distribution of Gd, Fe, and O is confirmed by energy dispersive X‐ray spectroscopy, proving the successful preparation of ternary compound NPs. The magnetic properties of the NPs show zero remnant magnetization typical of antiferromagnetic materials, and saturation at high fields that can be caused by spin interaction between Gd and Fe magnetic sublattices. The formation mechanism of ternary compound NPs in this novel plasma‐assisted method is also discussed. This method is also modified to demonstrate the direct one‐step deposition of thin films, opening up opportunities for their future applications in the fabrication of magnetic memory devices and gas sensors. [ABSTRACT FROM AUTHOR]

Early on, oxides were ruled out from superconductivity, since they are typically large-band-gap insulators. Nevertheless, a rather small number of them were found to be superconducting, with transition temperatures up to 14 K and a remarkably low carrier density. This was the starting point of K. Alex Müller (KAM) becoming interested in superconductivity in oxides. Step by step, he advanced the research on oxides and finally discovered, together with J. Georg Bednorz, high-temperature superconductivity (HTSC) in the perovskite-type compound Ba-La-Cu-O. Even though he was inspired by specific and clear ideas in his search, he added new impact in the understanding of HTSC for many years after receipt of the Nobel prize for this discovery. [ABSTRACT FROM AUTHOR]

We investigate perovskite oxides from different perspectives, namely their pseudo-harmonic dynamical properties, their dynamical properties when strong anharmonicity exists, and the intriguing functionalities arising from domain walls. Taking these viewpoints together yields a rather complex picture of this material class, which has not been found in previous approaches. It opens pathways to novel applications and reveals the rich ground states beyond the fictitious belief in the 'simplicity of perovskites and such structures'. [ABSTRACT FROM AUTHOR]

Ba2Bi0.572TeO6±δ and SrLa2NiFeNbO9 ceramics were prepared in polycrystalline form by conventional solid-state reaction techniques in air. The crystal structures of the title compounds were determined at room temperature from X-ray powder diffraction (XRPD) data using the Rietveld method. The Ba2Bi0.572TeO6±δ structure crystallizes in a triclinic space group I –1 with unit-cell parameters a = 6.0272(2) Å, b = 6.0367(1) Å, c = 8.5273(3) Å, α = 90.007(7)°, β = 90.061(2)°, and γ = 90.015(4)°. The tilt system of the BiO6 and TeO6 octahedra corresponds to the notation a – b – c –. The crystal structure of the SrLa2NiFeNbO9 compound adopts an orthorhombic Pbnm space group with lattice parameters a = 5.6038(5) Å, b = 5.5988(4) Å, and c = 7.9124(6) Å. The B O6 octahedra (B = Ni/Fe/Nb) sharing the corners in 3D. Along the c -axis, the octahedra are connected by O(1) atoms of (x , y ,1/4) positions; while in the ab -plane, they are linked by O(2) atoms of (x , y , z) positions. The bond angle of B –O1– B is 168.7° and that of B –O2– B is 156.3°. The octahedral lattice corresponds to the tilt pattern a – a – c +; it indicates that the octahedra tilt out-of-phase along the a , b -axes and in phase along the c -axis. [ABSTRACT FROM AUTHOR]

The reverse water‐gas shift (RWGS) reaction serves as a critical pathway for converting CO2 into diverse chemicals. The Mars–van Krevelen (MvK) mechanism, which leverages lattice oxygen as the oxidant and oxygen vacancies as reductants, offers an alternative catalytic strategy for the selective RWGS reaction. While Mn‐substituted SrTiO3 (i. e., SrTi0.8Mn0.2O3) has been shown to promote the RWGS reaction selectively via the MvK mechanism, achieving a sufficient conversion of CO2 necessitates elevated temperatures. This study investigated the effect of Pd‐loaded SrTi0.8Mn0.2O3 on the activation of adsorbed H2 molecules, which generated oxygen vacancies and enhanced CO2 conversion. Notably, 1.0 wt % Pd‐loaded SrTi0.8Mn0.2O3 yielded 13.4 % of CO at 673 K, whereas pristine SrTi0.8Mn0.2O3 and Pd‐loaded SrTiO3 yielded negligible or minimal amount of CO. Hydrogen temperature‐programmed reduction and X‐ray absorption spectroscopy measurements revealed that Pd promoted the formation of oxygen vacancies via both thermodynamic and kinetic mechanisms. Fourier transform infrared spectroscopy and kinetic studies revealed that the RWGS reaction over Pd‐loaded SrTi0.8Mn0.2O3 proceeded primarily via the MvK mechanism with a partial contribution from the Langmuir–Hinshelwood mechanism. This study underscores the effectiveness of combining metal and MvK‐type catalysts to enhance the efficiency of the RWGS reaction. [ABSTRACT FROM AUTHOR]

Lithium‐sulfur batteries face challenges like polysulfide shuttle and slow conversion kinetics, hindering their practical applications in renewable energy storage and electric vehicles. Herein, a solution to solve this issue is reported by using a cation vacancy engineering strategy with rational synthesis of La‐deficient LaCoO3 (LCO‐VLa). The introduction of cation vacancies in LCO‐VLa modifies the geometric structure of coordinating atoms, exposing Co‐rich surface with more catalytically active surfaces. Meanwhile, the d‐band center of LCO‐VLa shifts toward the Fermi level, enhancing polysulfide adsorption. Furthermore, multivalent cobalt ions (Co3+/Co4+) induced by charge compensation enhance the electrical conductivity of LCO‐VLa, accelerating electron transfer processes and improving catalytic performance. Theoretical calculations and experimental characterizations demonstrate that La‐deficient LCO‐VLa effectively suppresses the polysulfide shuttle, reduces the energy barrier for polysulfide conversion, and accelerates redox reaction kinetics. LCO‐VLa‐based batteries demonstrate exceptional rate performance and cycling stability, retaining 70% capacity after nearly 500 cycles at 1.0 C, with a minimal decay rate of 0.055% per cycle. These findings highlight the significance of cation vacancy engineering for exploring precise structure‐activity relationships during polysulfides conversion, facilitating the rational design of catalysts at the atomic level for lithium‐sulfur batteries. [ABSTRACT FROM AUTHOR]

The oxide surface structure plays a vital role in controlling and utilizing the emergent phenomena occurring at the interface of nanoarchitecture. A complete understanding of ternary oxide surfaces remains challenging due to complex surface reconstructions in various chemical and physical environments. Here a thermodynamic framework is developed to treat the stability of ternary oxide surfaces with finite temperature and chemical environments. Strontium titanate, as a representative ternary oxide, is used to establish the complete energy landscape of SrTiO3 (001) surface. The complete mapping yields a comprehensive understanding of various stable SrTiO3 surfaces with finite temperature and chemical potential or vapor pressure of the constituents, i.e., Sr (or Ti) metal and oxygen. This treatment also reveals a stable surface unknown yet with SrTi2O3 stoichiometry, which unveils the missing link between numerous previous experimental observations and the current understanding of SrTiO3 surface. Interestingly, the new surface shows an anisotropic surface‐localized metallic state originating from the characteristic surface structure. The findings would provide a viable way to understand ternary oxide surfaces and further utilize SrTiO3 surfaces for oxide nanoarchitectures. [ABSTRACT FROM AUTHOR]

Crystalline perovskite oxides are regarded as promising electrocatalysts for water electrolysis, particularly for anodic oxygen evolution reactions, owing to their low cost and high intrinsic activity. Perovskite oxides with noncrystalline or amorphous characteristics also exhibit promising electrocatalytic performance toward electrochemical water splitting. In this review, a fundamental understanding of the characteristics and advantages of crystalline, noncrystalline, and amorphous perovskite oxides is presented. Subsequently, recent progress in the development of advanced electrocatalysts for water electrolysis by engineering and breaking the crystallinity of perovskite oxides is reviewed, with a special focus on the underlying structure–activity relationships. Finally, the remaining challenges and unsolved issues are presented, and an outlook is briefly proposed for the future exploration of next‐generation water‐splitting electrocatalysts based on perovskite oxides. [ABSTRACT FROM AUTHOR]

Highlights Demonstrate that the key factor to determine the activity of reconstructed surfaces is the surface chemistry, instead of reconstruction degree using the popular perovskite LaNi1-xFexO3 oxides as model materials. Fe content can influence both the surface reconstruction degree, the activation degree, and the activity of reconstructed surfaces. The oxygen evolution reaction activity of reconstructed catalysts is primarily governed by the chemistry of the reconstructed surface species.

Controlling the in-plane magnetocrystalline anisotropy and interfacial exchange coupling between ferromagnetic (FM) layers plays a key role in next-generation spintronic and magnetic memory devices. In this work, we explored the effect of tuning the magnetocrystalline anisotropy of La2/3Sr1/3CoO3 (LSCO) and La2/3Sr1/3MnO3 (LSMO) layers and the corresponding effect on interfacial exchange coupling by adjusting the thickness of the LSCO layer (tLSCO). The epitaxial LSCO/LSMO bilayers were grown on (110)o-oriented NdGaO3 (NGO) substrates with a fixed LSMO (top layer) thickness of 6 nm and LSCO (bottom layer) thicknesses varying from 1 to 10 nm. Despite the small difference (∼0.2%) in lattice mismatch between the two in-plane directions, [001]o and [11̅0]o, a pronounced in-plane magnetic anisotropy was observed. Soft X-ray magnetic circular dichroism hysteresis loops revealed that for tLSCO ≤ 4 nm, the easy axes for both LSCO and LSMO layers were along the [001]o direction, and the LSCO layer was characterized by magnetically active Co2+ ions that strongly coupled to the LSMO layer. No exchange bias effect was observed in the hysteresis loops. In contrast, along the [11̅0]o direction, the LSCO and LSMO layers displayed a small difference in their coercivity values, and a small exchange bias shift was observed. As tLSCO increased above 4 nm, the easy axis for the LSCO layer remained along the [100]o direction, but it gradually rotated to the [11̅0]o direction for the LSMO layer, resulting in a large negative exchange bias shift. Therefore, we provide a way to control the magnetocrystalline anisotropy and exchange bias by tuning the interfacial exchange coupling between the two FM layers.

Sulfur is a promising anion dopant for exploring exotic physical phenomena in complex perovskite oxides. However, sulfurization to the epitaxial single-crystal oxide thin films with high crystallinity is experimentally challenging due to the volatility of sulfur element; thus, sulfurization effects on the associated properties have been scarcely studied. Here, we demonstrate an enhancement of ferroelectric polarization of epitaxial BaTiO3 thin films by sulfur doping. Initially, the epitaxial BaTiO3 thin films with high crystallinity were grown by pulsed laser deposition (PLD). Then, sulfurization to epitaxial BaTiO3 films was performed using a precursor of thiourea (CH4N2S) solution via a spin-coating technique. The crystalline structure of sulfurized BaTiO3 films was identified by X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM). The structural distortion with the elongated out-of-plane lattice constant was observed in the sulfurized BaTiO3 films. Atomic force microscopy (AFM) analyses also confirmed the surface morphology of films after sulfurization. Interestingly, we found an enhanced ferroelectric polarization in sulfur-doped BaTiO3 films accompanying the improved tetragonality in the crystal structure after sulfurization. The increments in the remnant (~34.8%) and saturated (~30.6%) polarizations of sulfurized BaTiO3 films were obtained in comparison with pure BaTiO3 films. Our work could be a primary study for a thorough understanding of the sulfur doping effect in perovskite oxides, opening up the potential of oxysulfide materials.

Reversible protonic ceramic electrochemical cell (R-PCEC) is a new energy conversion device that can achieve efficient conversion between chemical energy and electrical energy. However, the oxygen electrode has poor activity towards oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), which hinders the large-scale application of R-PCEC. Therefore, in order to improve the catalytic activity of oxygen electrodes, La 0.5 Sr 0.5 Co 0.2 Fe 0.8 O 3 (LSCF) is prepared using mesoporous silica SiO 2 (SBA-15) and polymethyl methacrylate (PMMA) as templates, and it was combined with BaZr 0.1 Ce 0.7 Y 0.2 O 3-δ (BZCY) to form a composite oxygen electrode for R-PCEC. Compared to the LSCF with solid-state reaction method, LSCF with hard-template method shows higher specific surface area and more oxygen vacancy, resulting in excellent ORR catalytic activity. In addition, LSCF prepared using PMMA as a template exhibits the best ORR catalytic activity, and the single cell with this composite oxygen electrode shows the highest maximum power density of 406 mW cm−2 in fuel cell (FC) mode with wet H 2 (3%H 2 O) and air as the fuel and oxidant, respectively. Additionally, it demonstrates a current density of −973 mA cm−2 at 1.3 V in electrolysis cell (EC) mode with wet air (10%H 2 O) as the oxidant. The single cell also shows good reversibility in FC mode and EC mode. This work provides a new strategy to improve the bifunctional activity of oxygen electrode in R-PCEC. [ABSTRACT FROM AUTHOR]

Oxygen evolution and reduction reactions (OER and ORR) play crucial roles in energy conversion processes such as water splitting and air batteries, where spin dynamics inherently influence their efficiency. However, the specific contribution of spin has yet to be fully understood. In this study, we intentionally introduce a spin channel through the transformation of trigonal antiferromagnetic SrCoO2.5 into cubic ferromagnetic SrCoO3, aiming to deepen our understanding of spin dynamics in catalytic reactions. Based on the results from spherical‐aberration‐corrected microscopy, synchrotron absorption spectra, magnetic characterizations, and density functional theory calculations, it is revealed that surface electron transfer is predominantly governed by local geometric structures, while the presence of the spin channel significantly enhances the bulk transport of spin‐polarized electrons, particularly under high current densities where surface electron transfer is no longer the limiting factor. The overpotential for OER is reduced by at least 70 mV at 150 mA cm−2 due to the enhanced conductivity from spin‐polarized electrons facilitated by spin channels, with an expectation of even more significant reductions at higher current densities. This work provides a clearer picture of the role of spin in oxygen‐involved electrocatalysis, providing critical insights for the design of more efficient catalytic systems in practical applications. [ABSTRACT FROM AUTHOR]

Exploring semiconductor materials with enhanced photocatalytic activity is essential for practical applications. This review provides a comprehensive overview of the photocatalytic reaction mechanisms. The discussion highlights recent progress in perovskite oxide materials for various environmental and energy applications, including H2/O2 production, organic pollutant degradation, heavy metal removal, radionuclide removal, CO2 reduction, and N2 fixation. The structural characteristics of perovskite oxides including titanates, tantalates, niobates, ferrites, and complex perovskite oxides are discussed, focusing on current strategies to enhance their photocatalytic activity. Furthermore, recent advances in the design and development of perovskite-based photocatalytic reactors are reviewed, emphasizing their potential for increased efficiency and practical implementation. This review aims to provide insights into the abilities, research gaps, future perspectives, and recommendations for further studies of perovskite oxide photocatalysts in addressing significant environmental and energy challenges. [ABSTRACT FROM AUTHOR]

Developing highly efficient catalysts for oxygen evolution reactions (OER) in complex water environments is crucial for promoting the photovoltaic electrolysis of water splitting for hydrogen production in arid areas. However, traditional catalysts often exhibit limitations in terms of reaction kinetics and electrode corrosion resistance. In this work, we successfully prepared a self-supporting perovskite complex oxide La0.7Sr0.3CoO3-δ/NF (LSC/NF) catalyst by means of simple hydrothermal synthesis combined with programmed annealing, and successfully applied to OER reaction in oilfield wastewater. In alkaline oilfield wastewater, at a current density of 10 mA cm−2, LSC/NF requires only 411 mV of overpotential, which is lower than that of LSC (493 mV) and traditional catalyst RuO2 (451 mV), suggesting a high OER catalytic activity. The good electrocatalytic activity can be attributed to its superhydrophilicity, increased electrochemical active surface area, faster reaction kinetics and higher oxygen vacancy concentration. This research offers valuable new insights for the development of OER electrocatalysts with high catalytic activity in complex water systems in arid areas. A self-supporting perovskite oxide catalyst La0.7Sr0.3CoO3-δ/NF was synthesized by a simple process combining hydrothermal and annealing. The growth of perovskite oxide nanosheets directly on the conductive nickel foam matrix gives the catalyst a strong hydrophilicity and significantly expands its electrochemical active surface area, thus enhancing the OER activity of LSC/NF in oilfield wastewater. [ABSTRACT FROM AUTHOR]

Perovskite oxide semiconductor is unique for its capability to form epitaxial heterostructures with both dielectric and metallic perovskite oxides. The study underscores the potential of perovskite oxides for multi‐layer stacking, a key aspect in advancing semiconductor technology as silicon‐based devices evolve toward 3D stacked structures. Fabrication of the first double‐level double‐gate field‐effect transistors (DL DG‐FETs) is demonstrated, where each layer is epitaxially grown using all‐perovskite oxides. This resulted in improvements in subthreshold swing, current drivability, and field effect mobility. This innovation not only highlights the distinctive potential of perovskite oxides but also provides new avenues for integration with other perovskite oxides on Si for more advanced electronic functions. [ABSTRACT FROM AUTHOR]

The preparation of highly active, rare earth, non-platinum-based catalysts for hydrogen evolution reactions (HER) in alkaline solutions would be useful in realizing green hydrogen production technology. Perovskite oxides are generally regarded as low-active HER catalysts, owing to their unsuitable hydrogen adsorption and water dissociation. In this article, we report on the synthesis of Li2ZrO3 perovskites substituted with samarium and terbium cations at A-sites for the HER. LSmZrO3 (LSmZO) and LTbZrO3 (LTbZO) perovskite oxides are more affordable materials, starting materials in abundance, environmentally friendly due to reduced usage of precious metal and moreover have potential for several sustainable synthesis methods compared to commercial Pt/C. The surface and elemental composition of the prepared materials have been confirmed by X-ray photoelectron spectroscopy (XPS). The morphology and composition analyses of the LSmZO and LTbZO catalysts showed spherical and regular particles, respectively. The electrochemical measurements were used to study the catalytic performance of the prepared catalyst for hydrogen evolution reactions in an alkaline solution. LTbZO generated 2.52 mmol/g/h hydrogen, whereas LSmZO produced 3.34 mmol/g/h hydrogen using chronoamperometry. This was supported by the fact that the HER electrocatalysts exhibited a Tafel slope of less than 120 mV/dec in a 1.0 M alkaline solution. A current density of 10 mA/cm2 is achieved at a potential of less than 505 mV. The hydrogen production rate of LTbZO was only 58.55%, whereas LSmZO had a higher Faradaic efficiency of 97.65%. The EIS results demonstrated that HER was highly beneficial to both electrocatalysts due to the relatively small charge transfer resistance and higher capacitance values. [ABSTRACT FROM AUTHOR]

The development of multi-functional and highly mixed ionic-electronic conductive perovskite oxide-based electrodes is becoming an established trend for designing and developing SOFC/SOEC reversible cells. Ideally, the same material can be employed at both electrodes provided that structural stability, high conductivity and catalytic activity are preserved in different operational atmospheres. Here, controlled Fe substitution with a small extent (0.5 mol%) of platinum at the B-site of a lanthanum strontium ferrite is proposed as an effective method to enhance the original oxide properties as both air and fuel electrode for solid oxide cells. The effects of low Pt-doping on La 0.6 Sr 0.4 FeO 3-δ structure, morphology and electrocatalytic activity are investigated and discussed. La 0.6 Sr 0.4 Fe 0.995 Pt 0.005 O 3-δ (05P-LSF) is first tested as air electrode, displaying lower area specific resistance as compared to the Pt-free perovskite. 05P-LSF structural stability and conductivity are assessed in 100 % CO 2 and 50 % CO 2 –50 % CO environments. Symmetric devices are then tested as SOECs in 100 % CO 2 , obtaining a current density output of 1.08 A/cm2 at 1.5 V. Electrochemical impedance spectroscopy (EIS) with distribution of relaxation times analysis (DRT) are used to provide insights on the electrode operation. Pt nanoparticle exsolution at the fuel electrode is induced by voltage application. The device stability under applied voltage is assessed for over 120 h. SOFC/SOEC characterization in a 50 % CO 2 /50 % CO mixture at 850 °C is also provided, obtaining a maximum power density of 270 mW/cm2 in SOFC mode, and a current density of 0.91 A/cm2 at 1.5 V in SOEC mode. [ABSTRACT FROM AUTHOR]

Strontium aluminate, with suitable lattice parameters and environmentally friendly water solubility, has been strongly sought for use as a sacrificial layer in the preparation of freestanding perovskite oxide thin films in recent years. However, due to this material's inherent water solubility, the methods used for the preparation of epitaxial films have mainly been limited to high-vacuum techniques, which greatly limits these films' development. In this study, we prepared freestanding single-crystal perovskite oxide thin films on strontium aluminate using a simple, easy-to-develop, and low-cost chemical full-solution deposition technique. We demonstrate that a reasonable choice of solvent molecules can effectively reduce the damage to the strontium aluminate layer, allowing successful epitaxy of perovskite oxide thin films, such as 2-methoxyethanol and acetic acid. Molecular dynamics simulations further demonstrated that this is because of their stronger adsorption capacity on the strontium aluminate surface, which enables them to form an effective protective layer to inhibit the hydration reaction of strontium aluminate. Moreover, the freestanding film can still maintain stable ferroelectricity after release from the substrate, which provides an idea for the development of single-crystal perovskite oxide films and creates an opportunity for their development in the field of flexible electronic devices. [ABSTRACT FROM AUTHOR]

In this work, we present theoretical calculations of the structural, electronic, optical and thermoelectric properties of the perovskite oxides LaMO3 (M = Ga or In) using density functional theory (DFT) with GGA–PBE approximation, as implemented in the ABINIT code. The cubic crystal structure of LaMO3 (M = Ga or In) compounds changes and its volume increases when the Ga atom is replaced by an In atom. In addition, negative formation energies suggest the thermodynamic stability of the studied compounds. Electron charge densities reveal an ionic bond between La and O, while the bond between M and O appears covalent. Electronic properties showed the indirect semiconducting behavior of LaGaO3 and LaInO3 perovskites. The calculated indirect bandgaps Eg (R–Γ) are found to be 3.34eV for LaGaO3 and 2.08eV for LaInO3. In addition, optical characteristics are determined in terms of real ε1(ω) and imaginary ε2(ω) parts of dielectric constant ε(ω), refractive index n(ω), absorption coefficient α(ω), reflectivity R(ω), energy loss function L(ω), optical conductivity σ(ω) and transmittance T(ω) are also studied. Optical absorption of light energy has been observed in both the visible and ultraviolet ranges, increasing the importance of the studied materials for optoelectronic applications. Finally, the thermoelectric performance of LaMO3 (M = Ga or In) materials has been explored using the Boltzmann transport theory implemented in the BoltzTraP software package. [ABSTRACT FROM AUTHOR]

The reforming reactions of greenhouse gases require catalysts with high reactivity, coking resistance, and structural stability for efficient and durable use. Among the possible strategies, exsolution has been shown to demonstrate the requirements needed to produce appropriate catalysts for the dry reforming of methane, the conversion of which strongly depends on the choice of active species, its interaction with the support, and the catalyst size and dispersion properties. Here, we exploit the exsolution approach, known to produce stable and highly active nanoparticle-supported catalysts, to develop iridium-nanoparticle-decorated perovskites and apply them as catalysts for the dry reforming of methane. By studying the effect of several parameters, we tune the degree of exsolution, and consequently the catalytic activity, thereby identifying the most efficient sample, 0.5 atomic % Ir-BaTiO3, which showed 82% and 86% conversion of CO2 and CH4, respectively. By comparison with standard impregnated catalysts (e.g., Ir/Al2O3), we benchmark the activity and stability of our exsolved systems. We find almost identical conversion and syngas rates of formation but observe no carbon deposition for the exsolved samples after catalytic testing; such deposition was significant for the traditionally prepared impregnated Ir/Al2O3, with almost 30 mgC/gsample measured, compared to 0 mgC/gsample detected for the exsolved system. These findings highlight the possibility of achieving in a single step the mutual interaction of the parameters enhancing the catalytic efficiency, leading to a promising pathway for the design of catalysts for reforming reactions. [ABSTRACT FROM AUTHOR]

Developing efficient O2 electrocatalyst is crucial for lithium-oxygen (Li-O2) batteries (LOBs). Among various catalysts, perovskite oxides have exhibited diverse catalytic activity owing to their low synthetic cost, tunable constitutions, flexible structures and excellent electrochemical stability. In this research, LaNi0.5Fe0.5O3 perovskites (LNFO) were synthesized via a classical sol–gel route combined with succedent calcination treatment. The ORR and OER tests indicate that the catalytic activity of LNFO calcined at 600 (LNFO-1) and 800℃ (LNFO-3) is superior to that of 700 (LNFO-2) and 900℃ (LNFO-4). To determine which sample is more suitable as a catalyst for LOBs, the LOBs with LNFO-1 and LNFO-3 electrodes were assembled. The LNFO-1 cathode shows discharge capacity of 1.7686 mAh under the current density of 100 mA g−1, which is higher than that with LNFO-3 cathode. The initial discharge–charge profiles of LOBs with LNFO-1 and LNFO-3 electrodes under a cutoff capacity of 1 mAh at 100 mA g−1 indicates that a lower overpotential could gained from LNFO-1 electrode. Meanwhile, 233 and 93 cycles can be realized under capacity limit of 0.15 and 0.315 mAh, respectively, at the current density of 100 mA g−1. The results demonstrate a lower overpotential, and longer circularity can be implemented in the LOB with LNFO-1 cathode, which can be put down to the larger specific surface area, and more presence of Ni3+ and Fe4+ in LNFO-1. Therefore, our work confirmed that the mesoporous LNFO-1 is a promising electrocatalyst for LOBs. [ABSTRACT FROM AUTHOR]

A domain‐resolved synchrotron single‐crystal X‐ray diffraction study of a LaAlO3 pseudo‐merohedral twin crystal was successfully carried out in combination with powder diffraction data from the same sample. Multiscale structure information ranging from micro‐ to nano‐ to atomic scale was determined from one single crystal. There is almost no change of domain ratios at temperatures of less than 400 K indicating no movement of the domain wall. The changes in domain ratio indicating domain‐wall movement were observed in the temperature range of 450 to 700 K, which is consistent with the result of the previous mechanical measurement. It is also found that the ratio of four twin components becomes equal (25%), just below phase transition temperature. These findings are important for domain engineering and theoretical studies related to LaAlO3. The temperature dependence of domain ratio was preserved in the heating and cooling cycle except for the first heating process to 840 K. Therefore, the domain structure after heating to 840 K is intrinsic to the crystal. Accurate structure parameters were determined through unit‐cell parameter calibration and domain‐resolved structure analysis. The method for calibration of unit‐cell parameters from twin crystal data was derived and used to solve the inconsistent unit‐cell parameters between single crystal and powder data in the present and previous studies. [ABSTRACT FROM AUTHOR]

In this study, lanthanum ferrites with strontium and magnesium-doped perovskite-type structures intended for energy storage were developed. Sr and Mg-doped lanthanum ferrites are constructed using the citrate auto-combustion dry gel technique. Several analytical tools were used to characterize the doped materials. Because the stabilization of mass loss happened above this temperature and no phase transformation was seen from thermo gravimetric analysis, the calcination procedure was carried out at 450 °C. The X-ray diffraction data has confirmed the existence of a single powder phase in the air-sintered materials and the mixing of the powdered phases during the calcination process. The presence of agglomerated sheets in the samples was revealed by scanning electron microscopy. The LSFM samples exhibit weak ferromagnetic interactions, according to the VSM analysis of the magnetization curve and the hysteresis loops. The electrochemical impedance spectroscopy showed that the 20% strontium and magnesium samples had better conductivity. These findings suggest that increasing the Sr and Mg content increases sample conductivity while decreasing the activation energy of the conduction process. As a result, the perovskite oxides synthesized in this study have the potential to be cathodes for supercapacitors and magnetic devices. [ABSTRACT FROM AUTHOR]

ABX3 (X = O) perovskite oxides are an uprising class of alternative electrocatalysts in eminent technologies like electrocatalysis, photocatalysis, thermocatalysis, and energy storage. The perquisites of perovskite oxide catalysts encompass ordered atomic structure, structural/compositional extensibility, flexible electronic structure, lucrativeness, and so on. The ingenuity to precisely control and tune the inherent properties by reconstructing their crystal structure is particularly advantageous in electrocatalysis reactions like oxygen reduction and evolution reactions (ORR and OER). Incorporating multidimensional imperfections in the presumably perfect crystal structure of the perovskite catalysts is garnering booming attention among researchers. This concept can expertly influence the electronic structure and boost the reaction kinetics during electrocatalysis. Defects or imperfections are achieved by substituting A‐ and/or B‐sites with heteroatoms or by oxygen vacancies. Defect engineering points to a promising new direction in the development of perovskite oxide catalysts. This work surveys the recent progress in defect engineering and how it plays a vital role in their design, and application in electrocatalysis, mainly ORR/OER. The architecture, dimensionality, and the types of perovskite oxides based on their cations, crystal structures, and stoichiometries are surveyed for a comprehensive understanding. This review aims to provide an extensive outlook on oxide perovskite catalysts concerning structural defects.

The interpretability of machine learning reveals associations between input features and predicted physical properties in models, which are essential for discovering new materials. However, previous works were mainly devoted to algorithm improvement, while the essential multi-scale characteristics are not well addressed. This paper introduces distortion modes of oxygen octahedrons as cross-scale structural features to bridge chemical compositions and material properties. Combining model-agnostic interpretation methods, we are able to achieve interpretability even using simple machine learning schemes and develop a predictive model of effective mass for a widely used material type, namely perovskite oxides. With this framework, we reach the interpretability of the model, understanding the trend of the effective mass without any prior background information. Moreover, we obtained the knowledge only available to experts, i.e., the interpretation of effective mass from the s–p orbitals hybridization of B-site cations and O2− in ABO3 perovskite oxides.

Abstract Crystalline perovskite oxides are regarded as promising electrocatalysts for water electrolysis, particularly for anodic oxygen evolution reactions, owing to their low cost and high intrinsic activity. Perovskite oxides with noncrystalline or amorphous characteristics also exhibit promising electrocatalytic performance toward electrochemical water splitting. In this review, a fundamental understanding of the characteristics and advantages of crystalline, noncrystalline, and amorphous perovskite oxides is presented. Subsequently, recent progress in the development of advanced electrocatalysts for water electrolysis by engineering and breaking the crystallinity of perovskite oxides is reviewed, with a special focus on the underlying structure–activity relationships. Finally, the remaining challenges and unsolved issues are presented, and an outlook is briefly proposed for the future exploration of next‐generation water‐splitting electrocatalysts based on perovskite oxides.

Abstract The oxide surface structure plays a vital role in controlling and utilizing the emergent phenomena occurring at the interface of nanoarchitecture. A complete understanding of ternary oxide surfaces remains challenging due to complex surface reconstructions in various chemical and physical environments. Here a thermodynamic framework is developed to treat the stability of ternary oxide surfaces with finite temperature and chemical environments. Strontium titanate, as a representative ternary oxide, is used to establish the complete energy landscape of SrTiO3 (001) surface. The complete mapping yields a comprehensive understanding of various stable SrTiO3 surfaces with finite temperature and chemical potential or vapor pressure of the constituents, i.e., Sr (or Ti) metal and oxygen. This treatment also reveals a stable surface unknown yet with SrTi2O3 stoichiometry, which unveils the missing link between numerous previous experimental observations and the current understanding of SrTiO3 surface. Interestingly, the new surface shows an anisotropic surface‐localized metallic state originating from the characteristic surface structure. The findings would provide a viable way to understand ternary oxide surfaces and further utilize SrTiO3 surfaces for oxide nanoarchitectures.

Perovskite oxides, renowned for their adaptable structure and optoelectronic characteristics, hold significant potential for applications in catalysis and photoelectrochemical (PEC) processes. In this research, the preparation of praseodymium iron oxide (PrFeO3) by spin coating and the impact of incorporating a calcium (Ca) dopant on its PEC efficacy as photocathodes are investigated. Spin coating of a polymer containing sol–gel yields thin films with uniform morphology and porosity, facilitating effective semiconductor/electrolyte interactions, as characterized by scanning electron microscopy analyses. Evaluation of transient photocurrent responses reveals that introducing Ca at a 5 at% doping level significantly enhances the PEC activity of PrFeO3, resulting in an optimal photocurrent of −124 μA cm−2 at +0.43 V vs. a reversible hydrogen electrode (VRHE) under simulated sunlight conditions. This enhancement is accompanied by an incident photon‐to‐current efficiency (IPCE) of 3.8% at +0.43 VRHE and 350 nm, along with an onset potential of +1.1 VRHE. Ultraviolet and visible spectroscopy analyses indicate an increase in light‐absorption capabilities in the Ca‐doped films and a noticeable reduction in bandgap compared to the undoped counterparts, further supported by IPCE measurements. In the findings, the significant role of dopants in augmenting the photocurrent performance of stable perovskite oxides, highlighting their potential in advancing photon conversion technologies, is underscored. [ABSTRACT FROM AUTHOR]