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Fe 2 O 3 is usually supported by inert materials to improve the sintering resistance and redox stability in chemical looping hydrogen generation (CLHG). It is reasonable to apply inert together with perovskite as a composite support for Fe-based oxygen carrier in CLHG. In this work, the Fe 2 O 3 /ZrO 2 /LaFeO 3 ternary oxygen carriers were synthesized, and the synergistic effects of ZrO 2 and LaFeO 3 on the reactivity and redox stability and the intrinsic mechanisms were investigated. The results showed that the 3LF (the mass ratio of LaFeO 3 and ZrO 2 was 30:10 with Fe 2 O 3 loading at 60 wt %) demonstrated the best hydrogen generation performance with an average H 2 yield of 8.3 mmol g-1 and H 2 purity of over 99.5%. The LaFeO 3 reacted with ZrO 2 to form pyrochlore La 2 Zr 2 O 7 with high melting point, which could be beneficial to the sintering resistance, though it led to the decline of the LaFeO 3 quantity. All the cycled samples exhibited a core-shell structure in view of Fe element distribution, owing to the outward migration of Fe cations. The ternary Fe-based oxygen carrier 3LF displayed the most desirable performance in hindering the Fe migration, resulting in enhanced sintering resistance. Furthermore, the high oxygen vacancy concentration in the 3LF facilitated the lattice oxygen transport and hence promoted the reactivity and redox stability in CLHG. • Fe 2 O 3 /ZrO 2 /LaFeO 3 ternary oxygen carriers were synthesized for CLHG. • 3LF demonstrated the highest reactivity and satisfactory redox stability. • La 2 Zr 2 O 7 with high melting point was beneficial to the sintering resistance. • 3LF inhibited outward migration of Fe cations and thus enhanced sintering resistance. • High oxygen vacancy concentration in 3LF facilitated the lattice oxygen transport. [ABSTRACT FROM AUTHOR]

The electrocatalytic N 2 reduction reaction (NRR) under ambient conditions is a green and sustainable method for ammonia (NH 3) synthesis, and the development of efficient electrocatalysts for NRR is a top priority. In recent years, LaFeO 3 has been widely used in the field of catalysis because of its high stability, low cost, and green advantages. Through strategies such as heteroatom doping and carbon loading, we can effectively increase the content of oxygen vacancies and improve the electrical conductivity of the material to produce composites with unique electronic structures and excellent catalytic properties. In the present work, we prepared single-atom doped LaFeO 3 /activated porous carbon composites (LFC/AC) for electrocatalytic NRR. The NH 3 yield and Faraday efficiency of LFC/AC were the highest at 23.876 μg h−1 mg−1 and 6.53% in 0.1 M Na 2 SO 4 electrolyte solution, both of which were higher than those of LFC. A series of characterizations and tests have shown that LFC/AC has excellent stability, electrical conductivity, and electrocatalytic properties. The density flooding theory (DFT) simulations were performed to explore the main mechanisms to improve the NRR performance of the materials. • Porous carbon is the LFC/AC with higher specific surface area. • The introduction of Cu atoms brings more oxygen vacancies to promote the NRR reaction. • The loose and porous structure is more conducive to the adsorption of N 2. [ABSTRACT FROM AUTHOR]

Reversible solid oxide cells (RSOCs) are prone to material thermal property mismatching problems between electrodes and electrolyte, which greatly reduces their energy efficiency and causes irreversible performance degradation. One solution is to develop symmetrical RSOCs (SRSOCs) employing identical electrode materials to effectively address thermal property mismatching related issues and also simplify the manufacturing process. Herein, La 1-x Sr x FeO 3-δ (x = 0–0.20) perovskites are developed and applied as both fuel and air electrode materials for SRSOCs for the first time. The impact of Sr substitution for La on the crystal structures, conductivities and electrochemical performance of LaFeO 3 oxides is systematically investigated. It is found, after doping with Sr, overall properties of the LaFeO 3 oxides show an obvious improvement, especially for the sample of La 0·9 Sr 0·1 FeO 3-δ (LSF9010). The peak power density of SRSOCs featuring LSF9010 can stand at 0.575 W cm−2 at 800 °C under the solid oxide fuel cell (SOFC) working model. Under solid oxide electrolysis cell (SOEC) model, the current density stands at 0.84 A cm−2 at 800 °C and 1.5 V. More importantly, the La 0·9 Sr 0·1 FeO 3-δ symmetrical cell can operate steadily for 128 h under SOFC mode and 25 h under SOFC-SOEC cycle mode, respectively, with almost no performance degradation found. The outcomes of the current study show that the developed LSF9010 may be used as an outstanding multifunctional electrode material in SRSOCs. • Sr doping LaFeO 3 perovskites firstly applied as both electrode materials in SRSOCs. • P max and electrolysis current density at 1.5 V of SRSOC with LSF9010 reaches 0.575 W cm−2 and -0.84 A cm−2, respectively. • SRSOC with LSF9010 shows superior long-term stability under both SOFC and reversible operating modes. [ABSTRACT FROM AUTHOR]

Narrow-band-gap LaFeO 3 (approximately 2.1 eV) has good thermal stability, and applications for light-driven water splitting. Thus, heterojunction catalyst containing LaFeO 3 and Au nanoparticles (NPs) are investigated for photoelectrochemical hydrogen production. The use of a citric acid or KOH modifier and calcination yields different LaFeO 3 particle morphologies and phases (La(OH) 3 alone or La(OH) 3 and La 2 O 3 , respectively), which affect the Au NPs coverage ratio. In addition, the formation of a heterojunction, the surface-plasma resonances (SPRs) effect, and the unique nanospikes on the Au NPs, red-shift happens in the light wavelength and reduce the photonic extinction to less than 2.1 eV. Further, in ethanol and l-butanol under AM 1.5G irradiation, more hydrogen is generated in the former than the latter at all tested temperatures. In addition, the activation energy for the formation of hydrogen is lower in ethanol than in 1-butanol. Finally, an amorphous structure is beneficial for photocatalysis. The total process involves (1) light absorbance, (2) electron-hole pair separation, (3) charge transfer via the SPRs effect, and (4) redox reactions on the catalyst surface in the following diagram. The hot electrons produced in the sea-urchin-like Au NPs can easily migrate to the CB of LaFeO 3 in all samples. [Display omitted] • Morphology, phases of LaFeO 3 tuned via hydrothermal reaction with KOH or citric acid. • LaFeO 3 decorated with Au nanoparticles, forming two-phase heterojunction. • Light-driven hydrogen generation in ethanol and 1-butanol tested. • Key factors and energy levels affecting reaction rate and mechanism identified. • Surface plasmon effect and catalyst morphology have key role in catalytic behavior. [ABSTRACT FROM AUTHOR]

Perovskite LaFeO 3 is considered as a promising new anode material for nickel/metal hydride batteries due to its low cost, environmental friendliness and high temperature resistance. However, the poor conductivity of LaFeO 3 material restricts the discharge ability, which is problematic for its future widespread application. To solve the above issue, in this study, we prepared C/Ni-coated LaFeO 3 composite in view of the excellent electrical conductivity of carbon and nickel metal. Results show that the C/Ni-coated LaFeO 3 composite delivers remarkably increased discharge capacity of ∼345 mAh g−1 at 60 ​°C in contrast to ∼267 mAh g−1 for pure LaFeO 3. Furthermore, the carbon and nickel not only increase the electrical conductivity of the LaFeO 3 but also reduces the agglomeration of the LaFeO 3 , therefore, the C/Ni-coated LaFeO 3 composite serves superior long cycle-life, which maintains 60.9% after 100 cycles (52.9% for the LaFeO 3 sample). In overall, the electrochemical behavior of the C/Ni-coated LaFeO 3 composite confirms its high potential as nickel/metal hydride batteries for energy storage applications. [Display omitted] • C/Ni-coating greatly improves the discharge capacity of LaFeO 3. • The C/Ni-coated LaFeO 3 delivers superior retention of 60.9% at 100th cycle. • The high rate discharge ability of C/Ni-coated LaFeO 3 reaches up to 47.3%. [ABSTRACT FROM AUTHOR]

LaFeO 3 is a type II multiferroic material which exhibits improper ferroelectricity induced by magnetic order (antiferromagnetism). However, the antiferromagnetic order limits its applications. This study demonstrates the induction of ferromagnetism in LaFeO 3 by doping with cobalt, varying the level of cobalt from 0 to 0.5 mol. Moreover, the effects of cobalt on the crystal structure, magnetic and dielectric properties are described. The XRD results show that at doping concentrations lower than 0.3 mol, LaFeO 3 maintains its orthorhombic structure (Pnma), while at higher cobalt concentrations the rhombohedral (R-3c) LaCoO 3 phase emerges. In addition, cobalt doping induces ferromagnetism because cobalt occupies iron positions until the solubility limit is reached (0.3 mol). All samples present high relative permittivity values, which increase with increasing cobalt content and temperature. Furthermore, the presence of cobalt results in a decrease in the dielectric dissipation factor for cobalt contents lower than 0.3 mol, due to the inhibition in the formation of vacancies. However, the presence of LaCoO 3 at high cobalt contents increases the dielectric losses due to the presence of a mixtures of phases. Moreover, the electric polarization curves exhibited weak ferroelectric behavior for ferrites with cobalt contents lower than 0.3 mol, and lossy improper ferroelectric type behavior for samples with higher contents. • High-energy ball milling enables the synthesis of pure cobalt-doped lanthanum ferrite. • Cobalt causes structural distortions that are quantified. • Structural distortion promotes double exchange magnetic interactions. • Cobalt induces ferromagnetism at room temperature in lanthanum ferrite. • Internal defects increase relative permittivity with low dielectric losses. [ABSTRACT FROM AUTHOR]

LaFeO 3 /MgFe 2 O 4 heterojunctions were prepared via the sol-gel route to enhance solar-light induced photo-persulfate degradation of tetracycline hydrochloride (TCH). LaFeO 3 /MgFe 2 O 4 exhibited the better removal efficiency of TCH in comparison to LaFeO 3 and MgFe 2 O 4. The photo-persulfate activity of LaFeO 3 /MgFe 2 O 4 was intensively affected by LaFeO 3 content, pH, and inorganic salts. Under the optimal conditions, 2-LaFeO 3 /MgFe 2 O 4 with a nominal LaFeO 3 content of 10 wt % presented the removal efficiency of 97.01 %, while declined to 85.40 % after ninth-cycle test. The lattice defects formed in LaFeO 3 and MgFe 2 O 4 acted as the active sites for TCH adsorption and photon capture. The oxygen-defected tight interface between LaFeO 3 and MgFe 2 O 4 was favorable for the separation and migration of photo-induce e-/h+ pairs, boosting solar-light response for photo-persulfate activity of LaFeO 3 /MgFe 2 O 4. However, the long-term photo-corrosion inevitably induced to the change in valance states of surface compositions, weakening the photo-persulfate performance in TCH elimination. [Display omitted] • LaFeO 3 /MgFe 2 O 4 hybrids were prepared via the sol-gel approach. • LaFeO 3 /MgFe 2 O 4 had the strong solar-light photo-persulfate activity for TCH degradation. • The tight interface favored the transfer and migration of photo-induced e-/h+ pairs. • Photo-induced radicals and Fe2+/Fe3+ couples promoted the persulfate oxidation. [ABSTRACT FROM AUTHOR]

Humidity sensors are omnipresent. Thus, significant efforts have been undertaken to advance their performance, for example, to have a fast detection time, negligible hysteresis, and excellent stability. Despite numerous active research endeavors, establishing a sensor that excels in all these key performances is still challenging. Here, we address this challenge by designing a capacitive-based humidity sensor employing porous LaFeO 3 perovskite. Integrating Ti into the perovskite using a sol-gel method, i.e. , LaFe 0. 925 Ti 0. 075 O 3 , results in a 400% increase in specific surface area achieved through pore formation, translating to a 2094% response parameter. Furthermore, due to the rapid equilibrium between adsorption and desorption processes, the sensor achieves ultrafast 4.4 s response time and 1.4 s recovery time, with <1% hysteresis and excellent stability over 28 days, when assessed at 300 K. Our work significantly advances current humidity sensor performance and, in a broader context, emphasizes the efficacy of porous (perovskite) materials for high performance gas detection. [Display omitted] • Incorporating Ti into LaFeO 3 introduces a tunable porosity and surface area in the perovskite. • The porous LaFe 0.925 Ti 0.075 O 3 exhibits ultrafast response/recovery times and negligible hysteresis. • This metrics puts the sensor among the highest-performing sensors in the literature. • The humidity sensing mechanisms is also explained though impedance measurement. [ABSTRACT FROM AUTHOR]

LaFeO 3 has been widely investigated as formaldehyde sensing material due to its enhanced performance. However, several disadvantages including the response/recovery speed, selectivity, and detection limit mortally restrict its practical applications. Along these lines, herein, platinum (Pt) functionalized LaFeO 3 porous structures were synthesized to optimize the sensing properties. The sensing test revealed that the best response value of Pt functionalized LaFeO 3 was around 2.5 times over that of the pristine material at the operating temperature of 125 °C. Meanwhile, the sensor also possessed the merits of shorter response/recovery time, better selectivity, and lower detection limits. From our analysis, it was demonstrated that the abundant pore structure and the increased adsorbed oxygen level are responsible for the excellent formaldehyde monitoring properties. Our work paves the way for the development of novel Pt functionalized LaFeO 3 porous structures, which can serve as a potential candidate for formaldehyde detection in many practical applications. [Display omitted] • Pt functionalized LaFeO 3 porous material was synthesized first time. • The response of Pt-LaFeO 3 sample is around 2.5 times over that of pure one. • The detection limit of Pt-LaFeO 3 sample can be achieved as low as 10 ppb. [ABSTRACT FROM AUTHOR]

Metal oxide semiconductors (MOSs) are widely utilized in the gas-sensing field owing to their superior gas sensing performances. Herein, a hierarchical nanostructure consisting of Bi 2 MoO 6 nanosheets (NSs) assembled on LaFeO 3 nanofibers (NFs) was successfully synthesized by combining an electrospinning with a solvothermal method. The full study of the sensing performances was conducted by manufacturing commercial gas sensors based on Bi 2 MoO 6 /LaFeO 3 hierarchical nanostructure in order to showcase its potential application in gas sensing. The results show that the sensor based on Bi 2 MoO 6 /LaFeO 3 hierarchical nanostructure exhibits excellent HCHO gas sensing performances including a high response (R a /R g = 36.5), a superior selectivity and a short recovery time (τ rec = 20 s). Additionally, sensors based on Bi 2 MoO 6 NSs and LaFeO 3 NFs were also respectively fabricated to measure HCHO gas sensing performances in order to elucidate the sensing mechanism and structural superiority of the Bi 2 MoO 6 /LaFeO 3 hierarchical nanostructure. The increased capability of detecting HCHO gas can be attributed to the n-p heterostructure formed within the Bi 2 MoO 6 /LaFeO 3 hierarchical nanostructure. The findings in this work can contribute to the realization to enhance the sensing performances by designing n-p heterostructure in gas sensing material. [Display omitted] • A 1D Bi 2 MoO 6 /LaFeO 3 n-p type hierarchical nanostructure is designed and synthesized. • The novel hierarchical nanostructure displays excellent HCHO gas sensing performance. • Heterostructure and 1D nanofibrous structure jointly promote the sensing performance. • Superb sensing performances come from the synergies among designed favorable factors. • Sensing mechanism and structural merits of hierarchical nanostructure are advanced. [ABSTRACT FROM AUTHOR]

Perovskite oxide LaFeO 3 with low cost has received increasingly attention as a new type anode material for proton insertion, however, the poor conductivity restricts its discharge ability for widespread application. Herein, to improve the conductivity of the LaFeO 3 , we prepare an in-situ cobalt coated LaFeO 3 by carbon reduction during which the gas generated reduces the agglomeration of LaFeO 3 at nucleation stage. The coated cobalt significantly improves the electrical conductivity of LaFeO 3 , thereby increasing both the rates of charge transfer and hydrogen diffusivity during discharge, which subsequently boost the discharge performance of LaFeO 3. Study shows that the Co-coated LaFeO 3 electrode with 15 wt% delivers remarkably increased discharge capacity of 260.2 mAh g−1 at 60 °C, in contrast to 162.5 mAh g−1 for pure LaFeO 3. Moreover, the LaFeO 3 -15 wt% Co also serves superior long cycle-life, maintaining 41.8% after 100 cycles, which is twice of the pure LaFeO 3. • Co coated in situ greatly improves the discharge capacity of LaFeO 3. • The CO 2 gas generated in the process of material synthesis inhibits the agglomeration of LaFeO 3. • Co coating improves the conductivity of the LaFeO 3 material itself. • The high rate discharge ability of LaFeO 3 –15 wt%Co reaches up to 15.82%. • LaFeO 3 –15 wt%Co delivers superior capacity retention of 41.8% at the 100th cycle. [ABSTRACT FROM AUTHOR]

[Display omitted] • LaFeO 3 with acid treatment (LFO-H) exhibited better CO oxidation performance to the raw material (LFO). • LFO-H possessed higher surface area, higher oxygen species concentration and better low-temperature reducibility. • LFO-H exhibited excellent thermal stability during the CO oxidation reaction. The rational design of low-cost catalysts with excellent catalytic activity is one of the most significant topics in heterogeneous catalysis. LaFeO 3 (LFO) perovskite was synthesized by the citrate sol-gel method and followed through a selective dissolution method by acid solutions. The surface element percentage, chemical states and pore structure of LFO were tuned. The acid-treated catalyst (LFO-H) showed higher activity in CO oxidation than the raw LFO. In terms of various characterizations, the exposed La ions of the LFO were slightly etched by dilute nitric acid, but the LFO-H still preserved the original perovskite framework. The corresponding surface area, surface oxygen vacancies and reducibility were also improved after acid treatment, accounting for its higher catalytic activity. Moreover, the LFO-H also exhibited excellent thermal stability because the perovskite structure remains after acid treatment. [ABSTRACT FROM AUTHOR]

Nano-sized La–Fe–O (LFO) structures were fabricated via novel free-solvent and green solid-state route using La (acac) 3. H 2 O and Fe (acac) 3 complex precursors. Acetylacetonate (acac) in organometallic complex precursors control nucleation and growth of formed crystals with creation spatial barrier around the cations, and prevent nano-product agglomeration. The mechanism of role of acac has been explained in nanostructure formation. Changing of parameters in synthesis reaction consisting La:Fe molar ratio, calcination time and temperature in turn offer a virtuous control over the nanocomposites size and shape which various compositions of La 2 O 3 /LaFeO 3 , LaFeO 3 /La 2 O 3 and LaFeO 3 /Fe 2 O 3 obtained. The as-prepared La–Fe–O nano-products were characterized thorough Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), UV–Vis, BET and energy dispersive X-ray (EDX) analysis in terms of crystallinity structure, composition, porosity and morphology. Different formed La–Fe–O nanostructures were evaluated for electrochemical hydrogen storage capacity through chronopotentiometry technique in stable current (1 mA). The achieved La–Fe–O nanoparticles could be applied as a favorable candidate active material for electrochemical hydrogen storage. Optical, magnetic and reducible characteristics of La–Fe–O nanostructures have positive effect on electrochemical hydrogen storage capacity. It was found out that the LaFeO 3 /Fe 2 O 3 nanocomposites have the best electrochemical hydrogen storage performance due to oxidation-reduction process of Fe2+/Fe3+ components which can help to charge-discharge process of hydrogen to increase the storage capability to 790 mAhg−1 after 20 cycles. Also, the mixed metal oxides illustrate advanced discharge capacity than other binary oxides. • Synthesis of La–Fe–O nanocomposites via cost-effective solid-state technique. • Investigation of divers synthesis circumstances on dimension properties of nanostructures. • Consideration of electrochemical hydrogen storage capacity of obtained nanostructures. • Discharge efficiency of 790 mAhg−1 after 20 cycles for LaFeO 3 /Fe 2 O 3 nanocomposites. [ABSTRACT FROM AUTHOR]

The catalytic combustion of methane has gained much attention as a sustainable technology, due to concerns about the environmental impact of unburnt methane emissions from the natural gas vehicles. Researchers have explored alternatives to precious metal catalysts for methane combustion, with a focus on perovskite oxides known for their excellent activity and sintering-resistance capacity. In this study, LaFeO 3 perovskite material was synthesized and subsequently subjected to a nitric acid etching treatment to modify its surface. It was found that the acid preferentially dissolved La cations from LaFeO 3 surface while the perovskite phase was unchanged, as a consequence, the etched LaFeO 3 shows improvement in methane combustion activity. The best performance was achieved in the sample with one-hour surface etched treatment, which suggests that the appropriate surface reconstruction induced by acid treatment promotes the formation of more active Fe sites on the surface and reduces the energic barriers of methane activation. This work presents a straightforward and effective approach to tailor the exposed surface properties of perovskites, thereby enhancing their activity in hydrocarbon combustion reactions. [Display omitted] • Nitrate acid treatment is performed to selectively etch the as-prepared LaFeO 3 perovskite for the surface modification. • Nitric acid preferentially dissolves La cations from LaFeO 3 surface, thus more Fe-O termination are exposed as active sites. • 1-h treated LaFeO 3 shows an enhanced CH 4 combustion reaction activity, due to the lowest energic barriers of CH 4 activation. • This work presents an effective approach to tailor the exposed surface properties of perovskites. [ABSTRACT FROM AUTHOR]

The Cu-LFO/Ni-LFO homojunction reduces the defects caused by the lattice mismatch at the interface and the recombination of photogenerated carriers. In addition, the relative positions of the Fermi energy levels of Cu-LFO and Ni-LFO are adjusted by ion doping to achieve the synergistic enhancement of photogenerated carrier separation by the triple synergy of applied voltage, energy band potential and built-in electric field. Meanwhile, Ni-LFO modulates the adsorption and desorption of water molecules and reduction reaction intermediates to accelerate the reaction kinetics at the semiconductor-electrolyte interface. [Display omitted] • Modulation of built-in electric field direction by metal ion doping; • Synergistic enhancement of photogenerated carrier separation; • Reduction of interfacial defects and photogenerated carrier recombination; • Ni-LFO served as co-catalyst-like agent to optimize HER reaction kinetics. LaFeO 3 (LFO), a typical p-type semiconductor, is considered as a promising material for photoelectric conversion because of its flexible composition and structure. However, its severe photogenerated carrier recombination and surface reaction kinetic hysteresis greatly limit its application in photoelectrochemistry (PEC) water splitting. Here, for the first time, a LFO p-p-type homojunction (Cu-LFO/Ni-LFO) formed by Cu-doped LFO and Ni-doped LFO is reported. Experimental investigation and density functional theory (DFT) calculations reveal that Cu and Ni doping forms a built-in electric field directed from Ni-LFO to Cu-LFO, which effectively improves the carrier separation and transport efficiency. The comparable crystal structure at the interface minimizes the photogenerated carrier recombination due to the interface lattice mismatch. In addition, Ni-LFO in contact with the electrolyte served as a co-catalyst like role in this PEC system, improving the kinetic properties of the surface reaction significantly by optimizing the adsorption and desorption of H 2 O molecules and HER reaction intermediates on the Fe in the active center whilst significantly reducing the energy barrier. As a result, the photocurrent density of the Cu-LFO/Ni-LFO photocathode reaches 5.94 mA cm2, which is 11 times higher than that of Cu-LFO and surpasses all LFO-based photocathodes reported so far. The LFO-based p-p homo-junction synthesized in this work is instructive for improving the carrier separation efficiency and surface reaction kinetics of LFO. [ABSTRACT FROM AUTHOR]

A composite photocatalyst KCN/LFO was synthesized using K-modified g-C 3 N 4 (KCN) and LaFeO 3 (LFO). The photocatalytic activity of the KCN/LFO was evaluated by degrading indole (heterocyclic organic compound). The KCN/LFO-10 (mass fraction of LaFeO 3 with 10%) displayed the highest removal rate of indole. Indole was degraded to 97.366% after 60 min. The photocurrent and electrochemical impedance spectroscopy (EIS) results suggested that the close correlation between KCN and LaFeO 3 can increasing the efficiency of photogenerated carrier separation. The capture experiment results demonstrated that ·O 2 − and ·OH is primary active substance, respectively. Moreover, the degradation efficiency of KCN/LFO-10 to indole remains stable at 87% after four successive experiments of indole photocatalytic degradation. This work presents an effective method for addressing the pollution caused by heterocyclic organic compound. • Synthesis and characterization of KCN/LaFeO 3 composite materials. • High charge separation in g-C 3 N 4 due to K modification. • 97.366% photo degradation of indole by unique band structure of KCN/LaFeO 3. • KCN/LaFeO 3 demonstrated excellent stability. [ABSTRACT FROM AUTHOR]

Possible mechanism diagram of the roles of oxygen vacancies in LaFeO 3 photocathodes in photoelectrochemical water splitting. [Display omitted] • A molten salt method for preparing Vo modified LaFeO 3 was demonstrated. • Proper amount of Vo can enhance bulk conductivity and light utilization of LaFeO 3. • The charge carrier density of LaFeO 3 in PEC reaction is not in line with the amount of Vo. • The optimal Vo loaded LaFeO 3 exhibits 3.27 times IPCE higher than that of the pristine LaFeO 3. In this study, we prepared oxygen vacancies (V O) modified LaFeO 3 particles using a simple molten salt method by tuning the cation (La3+) deficiency. The existence of V O was confirmed by studying its crystal structure and surface chemical state. By testing the photoelectrochemical (PEC) activity of the Vo modified La 1-x FeO 3-σ photocathodes in a 0.1 M NaOH electrolyte under visible light, the results demonstrate that the as-prepared La 0.9 FeO 3-σ shows good stability and superior IPCE, which is 3.27 times that of the pristine LaFeO 3. Even through V O modification is an effective strategy for regulating the PEC performance of a semiconductor, the charge carrier density in semiconductor is not directly proportional to the amount of V O , as excessive V O may lead to deterioration of the electrochemical reaction due to interfacial charge recombination. Introducing suitable amount of V O into LaFeO 3 can improve the light absorption, boost charge carrier transfer and separation efficiency, narrow the bandgap, and enhance the electrocatalytic reaction dynamics at the semiconductor surface. [ABSTRACT FROM AUTHOR]

Owing to the poor oxidizing and reducing properties of carbon dioxide (CO 2), there are few materials suitable for developing CO 2 semiconductor gas sensors, among which LaFeO 3 (LFO) has been proven to have CO 2 sensing properties. To enhance the CO 2 sensing performance of LFO, a Co doping strategy is proposed in this work. Specifically, the LFO and LaCo 0.1 Fe 0.9 O 3 (LCFO) nanoparticles were prepared via a simple sol-gel method, and the corresponding LFO and LCFO sensors were fabricated. The test results showed that the LCFO sensor exhibited wide detection range (25–10,000 ppm CO 2), fast response/recovery time (6/42 s), and higher response (6.69% to 1% CO 2) than that of LFO sensor at the optimal working temperature of 220 °C (51.9% relative humidity (RH)). In addition, the LCFO sensor showed good resistance to wide humidity range of 0–86.7% RH. Finally, the reasons for the enhanced CO 2 sensing performance of LCFO were analyzed combining characterization and theoretical calculation, which could mainly be attributed to the enhancement of oxygen vacancy and large adsorption energy caused by Co doping. This work provides a useful strategy to develop high-performance semiconductor CO 2 gas sensor. [Display omitted] • The CO 2 sensing performance of LaFeO 3 is improved by Co doping method. • The LaCo 0.1 Fe 0.9 O 3 (LCFO) sensor shows a wide detection range (25–10,000 ppm CO 2). • The LCFO sensor shows fast response/recovery times (6/42 s) for 5000 ppm CO 2. • The enhanced CO 2 sensing mechanism is analyzed using characterization and theoretical calculation. [ABSTRACT FROM AUTHOR]

• Ho-LaFeO 3 nanomaterials and composite with CNTs was fabricated by facile route. • Crystallite size was found to be <20 nm. • Photocatalytic degradation of Congo red and Benzoic acid was studied. • Ho-LaFeO 3 /CNTs degraded 83% Congo red and 69.5% Benzoic acid in 140 min. In this study, LaFeO 3 perovskite orthorhombic-shaped nanospheres and holmium-doped LaFeO 3 nanomaterials were prepared by a simple co-precipitation method. Their composite was made with carbon nanotubes (Ho-LaFeO 3 /CNTs) via an ultrasonication route. The X-ray Diffraction spectroscopy (XRD), Fourier Transform Infrared spectroscopy (FT-IR), Scanning Electron Microscopic analysis (SEM), Electrochemical Impedance Spectroscopy (EIS), and UV–visible spectroscopy, were done to analyze the prepared nanomaterials. Tauc plot was used to find the bandgap of prepared samples. The photocatalytic efficiency of prepared nanocrystals under visible light irradiation was investigated by degrading Congo red dye (colored pollutant) and Benzoic acid (colorless pollutant). The prepared Ho-LaFeO 3 /CNTs nanocomposite showed the highest photocatalytic efficiency compared to LaFeO 3 and Ho-LaFeO 3 samples as it degraded 83% Congo red and 69.5% Benzoic acid in 140 min, respectively. Carbon nanotubes helped in trapping the electrons and lower the recombination rate of e-/h+ pairs and as a result, increase the photocatalytic activity. [ABSTRACT FROM AUTHOR]

• The LFBC could maximize ROS generation through enhanced electron transfer. • The redox cycle of LaFeO 3 in concert with biochar exhibited optimal reaction rates and effectively inhibits metal leaching. • Non-radical pathways played a dominant role in the degradation process of SMX. • The degradation pathways and the ecotoxicity evaluation of the intermediates were presented. In this study, we prepared a novel biochar and LaFeO 3 -bonded nanosphere composite (LFBC) using a co-precipitation-pyrolysis method for the degradation of sulfamethoxazole (SMX). Under visible light conditions, LFBC-activated peroxymonosulfate (PMS) completely removed SMX within 25 min with rate constants 23 and 59 times higher than those of LaFeO 3 and biochar, respectively. Both free radical and non-free radical pathways participated in the SMX degradation process, with the non-free radical pathway playing a primary role. It is noteworthy that the interaction between LaFeO 3 and Biochar facilitated electron transfer and active sites, promoted the redox cycle of Fe3+/Fe2+, and greatly enhanced the catalytic performance of the composites. Degradation pathway and toxicity evaluation of pollutant removal processes in LFBC/PMS/vis systems based on intermediate identification and Fukui function calculations. This work proved the excellent synergistic performance of LFBC in light utilization and PMS activation, providing a potential utilization for efficient treatment of antibiotic wastewater and antibiotic-resistant bacteria. [ABSTRACT FROM AUTHOR]

Porous LaFeO 3 powders with high catalytic and photocatalytic activities were successfully synthesized by sol-gel method using nitrate and chloride precursors. The precursor effect on the crystal structure, morphology, specific surface area and optical properties of the prepared powders was fully determined. Thermogravimetric and X-ray diffraction analyzes showed the formation of the orthorhombic perovskite phase (Pnma, #62) at annealing temperature of 800 and 1000 °C for powder prepared by nitride and chloride salts, respectively. The scanning electron microscopy images revealed a significant effect of precursor type on nanoparticles morphology. It was found that powder prepared from chloride salts is more porous than that prepared with nitrate salts. The estimated surface area of LaFeO 3 nanoparticles ranges between 5.94 and 11.56 m2/g and the band gap varies from 2.19 to 2.27 eV. Methylene blue (MB) dye was used to investigate the catalytic and photocatalytic properties of LaFeO 3 powders. Both prepared powder types showed good catalytic activity and high photocatalytic performance under visible irradiation in removing MB dye. The adsorption kinetics data of MB molecules on LaFeO 3 nanoparticles are well fitted to the pseudo-first order model. Powder synthesized with chloride salts demonstrated high photodegradation efficiency of MB dye compared to that prepared by nitrate salts, which can be attributed to its relatively small band gap and high porosity. These two factors ensure a greater number of photogenerated electrons and more sites for photocatalytic reactions. [Display omitted] • LaFeO 3 nanoparticles were synthesized using two different precursors. • The morphology of LaFeO 3 powder was affected by the used precursor. • The adsorption of MB on LaFeO 3 nanoparticles was investigated via different kinetic models. • Chloride based powder showed high photocatalytic capacity of 100 %. [ABSTRACT FROM AUTHOR]

[Display omitted] • LFOBC catalyst exhibited 94.6 % TC removal in 60 min. • Fe3+/Fe2+, Cu2+/Cu+ dual redox centers played a key role in TC removal. • Identified •OH radicals as the major active species in the photo-Fenton process. • Degradation pathway and mechanism are explored. The rising number of contaminants released into the environment and the inadequacies of traditional wastewater treatment techniques have led to the demand for enhanced oxidation technologies like photo-Fenton. In this study, bimetal co-doped lanthanum orthoferrite (Bi x La 1-x Cu y Fe 1-y O 3 (x = 0, 0.01, 0.05, 0.1; y = 0, 0.01, 0.05, 0.1, 0.15)) based photo-Fenton catalysts with the in-built redox couples Fe3+/Fe2+, Cu2+/Cu+ and oxygen vacancies have been successfully synthesised via a facile one-pot solution combustion route. Systematic studies show that the Bi 0. 05 La 0. 95 Cu 0.1 Fe 0. 9 O 3 (LFOBC) exhibits an optimal photo-Fenton degradation rate of 0.0497/min for Tetracycline (TC) removal, being ∼ 1.8 and ∼ 6.2 times greater than Bi 0.05 La 0.95 FeO 3 (LFOB) and pristine LaFeO 3 (LFO) respectively. DFT analysis confirmed the better adsorption and dissociation of H 2 O 2 on a bimetal co-doped catalyst and identified the electron density difference in LFOBC, which can induce the H 2 O 2 dissociation. A detailed investigation of various influencing reaction parameters is explored. The degradation pathway for the LFOBC catalyst with the toxicological characteristics of each intermediate is analysed. This study presents the Bi 0.05 La 0.95 Cu 0.1 Fe 0.9 O 3 as a potential photocatalyst for enhanced photo-Fenton degradation with excellent efficiency observed for the degradation of various harmful pollutants for environmental remediation. [ABSTRACT FROM AUTHOR]

The niobium doping perovskite has been used in anode materials of solid oxide fuel cell. The electronic properties and structural stability of LaFeO 3 (LFO) oxide by Nb-doping and the adsorption of H 2 molecule at the clean and Nb-doped LFO (001) surface are investigated by theoretical calculations. The calculated results reveal that the band gap of the orthorhombic LFO is 2.04 eV and the gap disappears after the Nb-doping, which improves the electrical conductivity. The Nb-doping increases the formation energy of oxygen vacancy in orthorhombic LFO. The calculated results of binding energy and formation enthalpy imply that the structural stability is strengthened after Nb-doping, which provides a theoretical explanation for recent experimental observations. This result can be attributed to the change of electronic structure after the Nb-doping. The bond mechanisms for LFO and Nb-doped LFO are obtained by analyzing density of states, Mulliken charges and bond population. Based on adsorption properties, it can be found that the adsorption of H 2 molecule is slightly enhanced after Nb-doping and the Nb-doping facilitates that H 2 molecule dissociates to H atoms. These results could provide powerful interpretations for the origin of experimental phenomenon. • After Nb-doping, the DOS crosses the Fermi level and the gap disappears. >. • The Nb doping improves the structural stability of LaFeO 3.>. • The adsorption of H 2 is slightly enhanced after Nb doping.>. [ABSTRACT FROM AUTHOR]

In this paper, the resonance behavior of LaFeO 3 in the GHz range was investigated. Synthesis of LaFeO 3 , by solid state reaction between Fe 2 O 3 and La 2 O 3 , was confirmed by X-ray diffractometry. LaFeO 3 exhibited dielectric resonance and magnetic resonance, which can lead to negative permittivity and negative magnetic permeability. By controlling sample synthesis parameters, specifically sintering temperature, the peak in negative permeability can be tuned between 2.6 and 2.8 GHz, while the peak in negative permittivity can be tuned between 0.8 and 1.2 GHz. This material can be applied to fields such as electromagnetic metamaterials, where it could be used to increase the gain of an antenna, or to control the transmission of microwaves. [ABSTRACT FROM AUTHOR]

• A good performance of SR-Photo-Fenton under visible light was obtained. • The predictable and mathematical kinetic model was established for SR-based AOP. • The reaction mechanism of SR-Fenton assistance with visible light was proposed. In this work, a novel sulfate radical (SR)-visible light-Fenton mediated by LaFeO 3 (LFO) under visible light was established and its performance on Rhodamine B (RhB) dye wastewater degradation was evaluated. Herein, peroxymonosulfate (PMS) was able to be activated by a synergic effect of visible light energy and LFO to form SR and hydroxyl radical (·OH). All RhB (initial concentration was 20 mg L−1) degradation was reached at 180 min under visible light irradiation in the presence of 3.552 mM PMS and 1.0 g L−1 LFO. All reactions followed the observed pseudo -first order reaction kinetics, including effects of [PMS], [catalyst], optical power density and initial solution pH. Based on the investigation of above parameters effects on RhB degradation in SR-photo-Fenton, a predictable and empirical mathematical kinetic model was proposed. Additionally, the reactive oxygen species (ROS) formed in this SR-visible light-Fenton were identified by quenching experiments, as that SO 4 −· and ·OH dominated oxidation. At last, the reaction mechanism of this novel SR-visible light-Fenton was suggested based on the qualitative/quantitative analysis of major intermediates of RhB and the identified ROS in SR-visible light-Fenton mediated by LFO. [ABSTRACT FROM AUTHOR]

A novel hydrogenated LaFeO 3 was fabricated and firstly used as photocatalyst in the application of visible-light photocatalytic decomposition of organic contaminant. Through the adjusting of annealing atmosphere and temperature, a series of treated LaFeO 3 with oxygen vacancies were obtained. Compared with untreated LaFeO 3 and argon treated LaFeO 3 , hydrogenated LaFeO 3 photocatalysts exhibited higher catalytic ability. This notably improved catalytic ability was mainly assigned to the formation of disordered layer on the surface of hydrogenated LaFeO 3. The surface oxygen vacancies of LaFeO 3 caused by hydrogenation were beneficial to light absorption and separation of photogenerated carriers. In this system, we found the amount of surface oxygen vacancies had a direct impact on the catalyst ability of hydrogenated LaFeO 3 photocatalysts. In addition, the magnetic hydrogenated LaFeO 3 photocatalysts were stable, and reused after five times without obvious decrease of catalytic ability. [ABSTRACT FROM AUTHOR]

A Pr-doping strategy was used to improve traditional strontium-doped lanthanum ferrite oxides for proton-conducting solid oxide fuel cells (SOFCs). Three different samples, La 0.5 Sr 0.5 FeO 3- δ , La 0.25 Pr 0.25 Sr 0.5 FeO 3- δ , and Pr 0.5 Sr 0.5 FeO 3- δ ,were successfully prepared. The Pr content was shown to have an obvious influence on the hydration ability of the materials. Hydration was improved at higher Pr-contents, suggesting a promising cathode performance. However, the improved hydration ability did not always lead to an increased fuel cell performance, and it was found that the fuel cell performed best when an appropriate Pr-doping amount was used that resulted in a good compromise between protonic and oxygen-ion conduction. As a result, the optimized composition La 0.25 Pr 025 Sr 0.5 FeO 3- δ generated a high peak power density of 616 mW cm−2 and a low polarization resistance of 0.09 at Ω cm2 at 700 °C, which is an encouraging performance for a traditional cathode material. [ABSTRACT FROM AUTHOR]

[Display omitted] • LFTCO absorbent was created by introducing Ti and Co transition metals in B sites of perovskite oxides LaFeO 3. • Ferromagnetic LFTCO exhibits a methyl blue adsorption capacity (q max) of 2131 mg/g. • The electrostatic force and chelation linkage were the main driving forces in the chemisorption of MB on LFTCO. • A novel dual-doped method gives LFTCO exceptional adsorption capabilities and Fenton-based regeneration potential. Creating adsorbents that exhibit high selectivity towards pollutants, can be readily regenerated, and maintain high stability, remains a crucial challenge in water treatment technology. Herein, we present a magnetically and chemically recoverable absorbent based on Ti and Co co-substituted LaFeO 3 (La 0.9 Fe 0.55 Ti 0.3 Co 0.15 O 3 , LFTCO) with significantly enhanced adsorption properties. Notably, LFTCO exhibits a methyl blue adsorption capacity (q max) of 2131 mg/g, setting a new record among perovskite oxides, due to the increased surface oxygen vacancy with the dual doping strategy. The selected dual-dopant consists of Fenton active Co and spin-state interactive Ti, which allows creating more oxygen vacancy and simultaneously facilitating pragmatic regeneration of the adsorbent. The new LFTCO exhibits significantly enhanced ferromagnetism (M = 7.27 emu/g), enabling rapid magnetic separation from water and subsequent Fenton-based regeneration step. We also reveal that the anchored configuration of SO 3 -defect site, through density functional theory (DFT) calculation, as the most favorable site for the adsorption process. These findings provide a pathway to creating high-performance adsorbents and shed light on the mechanistic understanding of LFTCO's enhanced adsorption properties. [ABSTRACT FROM AUTHOR]

Enhanced optical absorption of LaFeO 3 perovskite coatings achieved through the modulation of bandgap and free carriers via Ca/Ni co-doping, culminates in exceptional photothermal conversion performance under solar and infrared irradiations. [Display omitted] • Microstructural evolution of perovskite LaFeO 3 -based coatings. • High optical absorptivity of ∼90 % in the wavelength range of 0.3–14 μm. • Light absorption mechanisms of A/B-sites co-doped LaFeO 3. • Photothermal conversion performance under the solar and infrared irradiations. Perovskite-type oxides (ABO 3) are widely acknowledged as novel light-absorbing materials owing to their adaptable composition, distinctive oxidation states, and customizable physicochemical properties. In this study, we reported a series of A-site or A/B-sites doped LaFeO 3 -based ceramic coatings for photothermal conversion. An exhaustive investigation was undertaken to explore the effects of doping element on the microstructure, microchemistry, and optical properties of the ceramic coating. Among all the samples, the La 0.5 Ca 0.5 Fe 0.95 Ni 0.05 O 3 coating exhibits the highest absorptivity in the solar spectrum (300–2500 nm) and in the wavelength range of 0.3–14 μm, reaching 92.2 % and 88.1 %, respectively. Furthermore, it demonstrated the superior photothermal conversion performance under solar and infrared radiation. Complementary first-principles calculations provide fundamental principles for comprehending the light absorption enhancement mechanisms in LaFeO 3 -based materials, revealing the complex interplays between crystal structure, band structure, and light absorption. The experimental findings, along with the results of first-principles calculations, demonstrate that the doping of Ca or Ca and Ni can effectively reduce the bandgaps and induce lattice distortions, thereby enhancing the light absorption in the visible and infrared wavebands. This work presents a facile method to prepare LaFeO 3 -based coatings with different morphologies, providing a novel option for high-temperature photothermal conversion applications. [ABSTRACT FROM AUTHOR]

Metal oxides based semiconductors promise high performance gas sensing owing to their robustness and low cost, but are limited by their unsatisfied adsorption ability and intrinsic low carriers' mobility. We herein demonstrate an efficient strategy of reducing the adsorption energy and improving the carrier mobility via bulk implanted TiO 2 nanocrystals (NCs) in LaFeO 3 porous structure. By implanting laser generated sub-3 nm TiO 2 NCs in LaFeO 3 samples, the response value (221.8 for 100 ppm formaldehyde) increases about 4 times comparing with that of pristine. Additionally, the sample exhibits high sensitivity and fast response/recovery speed toward formaldehyde steam. The detailed analyses and theoretical calculation proves that the TiO 2 NCs could cause the increase of adsorbed oxygen levels as well as the carrier mobility through forming the heterojunction with LaFeO 3. This work verifies that TiO 2 NCs implanted LaFeO 3 is a promising formaldehyde sensing material, which provides a new approach to improve sensing ability of metal oxide semiconductor (MOS) based gas sensors. [Display omitted] • TiO 2 nanocrystals/LaFeO 3 p-n Junctions was produced first time. • LFO-1.5 TiO 2 sample exhibits high sensitivity and fast response to formaldehyde. • DFT calculation reveals adsorption energy decreases after modification of TiO 2 NCs. [ABSTRACT FROM AUTHOR]

• LaFeO 3 nanoparticles were synthesized through a sol–gel method. • Commercial rutile TiO 2 nanoparticles were utilized as heterostructure material. • TiO 2 -LaFeO 3 nanocomposites exhibited improved acetone sensing performance. To enhance the acetone sensing capabilities of LaFeO 3 nanoparticles for practical applications in breath analysis, commercial n-type rutile TiO 2 nanoparticles were utilized as additives and directly mixed with LaFeO 3 nanoparticles synthesized via a sol–gel method. The obtained TiO 2 -LaFeO 3 nanocomposites were characterized by XRD, SEM, BET, and XPS. Compared to pure LaFeO 3 nanoparticles, the resulting TiO 2 -LaFeO 3 nanocomposites exhibited higher surface reactivity, as evidenced by their larger specific surface areas and higher oxygen vacancy contents. The introduction of TiO 2 also facilitated the formation of p-n heterojunctions, which enhanced the regulation of acetone molecules on internal carrier conduction within the nanocomposites. Therefore, the TiO 2 -LaFeO 3 nanocomposites demonstrated improved acetone sensing performance, including higher vapor response values, selectivity, and faster response/recovery speeds. Among the series of nanocomposites, those with an addition of 10 wt% TiO 2 exhibited the highest vapor response value (37.3 to 100 ppm) and the greatest selectivity against methanol and ethylene glycol at the prime operating temperature of 144 °C. [ABSTRACT FROM AUTHOR]

Reasonable design of heterojunction photocatalysts with high-quality interfacial coupling is an effective way to improve the photocatalytic activity of semiconductors. Herein, we successfully decorated Zinc indium sulfide (ZnIn 2 S 4 , ZIS) on perovskite Lanthanum ferrite (LaFeO 3 , LFO) with more active sites by a pre-hydrothermal combined post-calcination method, and constructed S-scheme heterojunction photocatalyst with a unique hollow corncob-like morphology for efficient photocatalytic hydrogen production and tetracycline (TC) degradation. When the mass ratio of LFO is 35% and 15%, the ZIS/LFO photocatalyst exhibits the best hydrogen evolution rate and TC photodegradation performance, respectively. Notably, the optimum hydrogen production rate is 6 times that of pure ZIS with excellent cycling stability. The enhanced photoactivity can be explained by the hollow corncob-like morphology and the formed S-scheme heterojunction with close interface contact between ZIS and LFO, which significantly improves the spatial separation and migration efficiency of photoexcited carriers, while maintaining a high redox potential. Finally, it provides an effective support for the photocatalytic mechanism through calculation results of density functional theory. This work not only provides a novel construction strategy of photocatalysts for efficient photocatalytic hydrogen evolution and organic pollutant degradation, but also opens up a new insight for perovskite-modified S-scheme heterojunction. [Display omitted] • Hollow corncob-like ZnIn 2 S 4 /LaFeO 3 were synthesized by a calcination method. • Hollow corncob structure could distinctly improve the charge-carriers transfer. • The ZnIn 2 S 4 /LaFeO 3 -35% hydrogen production is 6 times than that of pure ZIS. • The optimal degradation ratio of tetracycline reaches 100% in 40 min. • A S-scheme photocatalytic mechanism was proposed. [ABSTRACT FROM AUTHOR]

Since triethylamine (TEA) is potentially harmful to the human body and the environment, it is necessary to create an efficient gas sensor for TEA decoration. In this work, novel catalytic RuO 2 nanoparticles-functionalized LaFeO 3 porous microspheres with high triethylamine-sensing performances were obtained via a simple hydrothermal method. The RuO 2 /LaFeO 3 composites were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS). Characterization results revealed that RuO 2 nanoparticles were homogeneously attached on the surface of porous LaFeO 3 microshperes. Gas-sensing tests exhibit that RuO 2 /LaFeO 3 nanocomposites show higher sensitivity, excellent selectivity and fast response and recovery towards trimethylamine (TEA). This work confirms the advantages of RuO 2 catalyst-loaded in gas detection. The RuO 2 /LaFeO 3 nanocomposites could be a promising candidate material for fast detection of trimethylamine. Image 1 • RuO 2 nanoparticles-functionalized LaFeO 3 porous microspheres were obtained via a simple hydrothermal method. • RuO 2 /LaFeO 3 nanocomposites show enhanced sensing properties to triethylamine. • This work confirms the advantages of RuO 2 catalyst-loaded in gas detection. [ABSTRACT FROM AUTHOR]

LaFeO 3 -doped hierarchically mesoporous/macroporous silica (LFO/MMS) was prepared for the first time by impregnation method and then calcination. The sample was characterized in detail, suggesting the successful incorporation of LFO into MMS which was consisting of mesopores and macropores. The high surface area, accessible pores as well as low band gap energy supported its high performance towards efficient photoassisted-Fenton degradation of dye under visible light irradiation. Rhodamine B (RhB), which has been widely used as one of typical synthetic dyes in textile industry, was selected as the dye model. It was found that the incorporation of LFO into the MMS support induced a significant enhancement in the visible-light photo-Fenton catalytic performance, as compared with pure LFO. The degradation rate using LFO/MMS under the conditions (temperature = 25 °C, catalyst dosage = 1 g L−1, initial dye concentration = 10 mg L−1, initial H 2 O 2 concentration = 10 mM and initial pH = 6) was 95.6% after 90-min exposure to the visible light. This was 7% and 19.8% greater than that of LFO and MMS, respectively. In particular, the pseudo-first-order reaction rate constant for LFO/MMS was 0.0367 min−1, which was approximately 2 times higher than that for pure LFO (0.0215 min−1). The newly developed catalyst, LFO/MMS, showed a good stability for recycle and reuse, which is crucial for its potential use in industrial application. • LaFeO 3 -doped mesoporous/macroporous silica was studied for photo-Fenton. • Its structure and bandgap supported efficient photo-Fenton degradation of dye. • It was much more effective in removing dye compared to pure LaFeO 3. • Its use was optimized by varying solution pH, H 2 O 2 and catalyst concentration. • It showed good stability and reusability. [ABSTRACT FROM AUTHOR]

• A series of novel p-LaFeO 3 /n-ZnO heterojunction photocatalysts were prepared. • 20%-p-LaFeO 3 /n-ZnO has optimal activity for phenol degradation under visible light. • The ·OH was main active species in phenol photodegradation process. • 3D-EEMs was used to investigate the possible mechanism of phenol degradation. A series of catalysts with p-LaFeO 3 /n-ZnO heterostructure were designed and prepared by hydrothermal method. The structure, surface topographies, optical properties and interfacial interactions of these photocatalysts were analyzed by XRD, SEM, TEM, PL, Uv–vis DRS, XPS, COD, TOC etc., indicating that p-n heterojunction formed at the interface between p-LaFeO 3 and n-ZnO, which enhanced the photocatalytic activity. Among them, the 20%-p-LaFeO 3 /n-ZnO composite exhibits the best activity for the phenol degradation under visible light. The superior photocatalytic activity of the heterojunction photocatalyst is mainly attributed to the formation of p-n heterojunction which leads to an efficient separation of photogenerated electron-hole pairs. Besides, the 20%-p-LaFeO 3 /n-ZnO heterojunction photocatalyst shows the excellent photocatalytic stability after 4 cycles. And from the free radical capture experiment, the degradation of phenol is dominated by the oxidation reaction of hydroxyl radicals and direct hole oxidation. What's more, certain intermediates were detected by HPLC and 3D-EEMs. Therefore, a photocatalytic mechanism of the 20%-p-LaFeO 3 /n-ZnO p-n heterojunction catalyst for phenol degradation under visible light irradiation was proposed. [ABSTRACT FROM AUTHOR]

LaFeO 3 was prepared via simple, economical and environmentally friendly auto-combustion methods using different fuels, including citrate, urea, sucrose, egg whites, gelatin and chitosan. The prepared ferrites were systematically characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, high resolution transmission electron microscopy (HRTEM), vibrating sample magnetometry (VSM) and electrical measurements to study the impact of the synthetic routes on the various properties. XRD showed the formation of a single orthorhombic phase, except for the samples prepared via egg white, gelatin and urea methods, which indicated a secondary La 2 O 2 CO 3 phase. The FT-IR and TEM studies confirmed the formation of the phase. Differential thermal analysis-thermogravimetry techniques (DTA-TG) were used to characterize the auto-combustion process up to ferrite formation. The obtained unsaturated magnetization for all of the samples suggested the presence of anti-ferromagnetic ordering in addition to weak ferromagnetic ordering. The egg white method showed higher magnetization (1.78 emu/g), while the urea and chitosan methods indicated lower magnetization (0.13 emu/g). The coercivity measurements confirmed the presence of ferromagnetic/anti-ferromagnetic interfaces with higher values than those reported in the literature. The AC-conductivity measurements indicated semiconducting characteristics and exhibited a change in the conduction mechanism from hopping to polaron conduction by increasing the temperature. LaFeO 3 prepared via the egg white method indicated an anti-ferromagnetic/paramagnetic transition at approximately 715 K. The dielectric measurements confirmed the AC-conductivity results and exhibited values higher than those reported in the literature. [ABSTRACT FROM AUTHOR]

Perovskite LaFeO 3 nanoparticles with a size of less than 50 nm have been synthesized by sol-gel method using citric acid, oxalic acid, and succinic acid as chelating agents. The obtained products were characterized by various techniques like XRD, FT-IR, HRTEM, and SAED. The elemental composition was analyzed by EDX. The magnetic and ferroelectric properties were investigated using VSM and Precision multiferroic tester. Batch experiments were conducted to test the ability of LaFeO 3 samples for removal of cadmium (Cd2+) from the contaminated water. The concentration of heavy metal ion was monitored by AAS technique. Adsorption studies revealed that the LaFeO 3 prepared by succinic acid possess high adsorption capacity. Image 1075 • Perovskite LaFeO 3 nanoparticles of the size (<50 nm) have been synthesized by sol-gel method. • Magnetic, ferroelectric and leakage properties were investigated. • Perovskite LaFeO 3 shown good performance towards removal of cadmium ions. [ABSTRACT FROM AUTHOR]

• LaNi x Fe 1- x O 3 (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) as photothermal catalysts reduction of CO 2 with H 2 O vapor to CH 4 and CH 3 OH. • The solid solutions possesses lead to a significant modification with the quantity of oxygen vacancies and band gaps. • LaNi 0.4 Fe 0.6 O 3 compound exhibits the best photothermal catalytic performance. LaNi x Fe 1- x O 3 perovskite compounds (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) were successfully synthesized by a sol-gel combustion method. The crystal structure, morphology, BET surface area, oxygen vacancies, band gap and catalytic properties of the catalyst were characterized in detail. The results showed that LaNi 0.4 Fe 0.6 O 3 compound exhibits the best photothermal catalytic performance. Under the same catalytic conditions (350 ℃ + Vis-light), CH 4 and CH 3 OH yields are about 3.5 and 4.0 times, 1.8 and 2.1 times of that of LaFeO 3 and LaNiO 3. It was found that all the solid solutions possesses better catalytic properties than the pure end compounds. The doping of Ni lead to a significant modification with the quantity of oxygen vacancies and band gaps. These findings may further broaden the materials scope for photothermal conversion of CO 2 and H 2 O. [ABSTRACT FROM AUTHOR]

Abstract LaFeO 3 micro-spindles with intriguing structural characteristics were synthesized using cyano-bridged coordination polymers as sacrificial templates. Within a longitudinal dimension of less than 5 µm, each micro-spindle features a hollow center contained in a mesoporous shell with hexagonal cross section. Conductometric gas sensors developed from these micro-spindles demonstrate a comprehensively improved NO 2 -sensing performance over other-reported LaFeO 3 devices, including lower operating temperature (155 °C), higher sensitivity (response of 81.4% under 5 ppm) and expedited response and recovery (40 s/329 s). Such performance is enabled by a semiconducting mechanism governed by the formation and catalytic dissociation of nitrite species during NO 2 adsorption on LaFeO 3 , facilitated by the special hierarchical structure of the micro-spindle. [ABSTRACT FROM AUTHOR]

Abstract Diclofenac was frequently found in various waters, indicating conventional wastewater treatment methods ineffective in its removal. In this study, LaFeO 3 (LFO) was synthesized and its catalytic activity of LFO as the activator of different oxidants such as persulfate (PS), hydrogen peroxide and peroxylmonosulfate (PMS) was evaluated in terms of DCF degradation. The influence of calcination temperature was examined on the catalytic activity of LFO. The effects of various parameters including pH levels, PMS concentration, LFO dose and initial DCF concentration were investigated on DCF degradation rate. The marginal effects of PMS concentration and LFO dose were compared. Langmuir-Hinshelwood (LH) model was used to quantitatively describe DCF degradation reaction in LFO/PMS system. The two constants, k (Limiting reaction rate at maximum coverage) and K (Equilibrium adsorption constant), were determined on the basis of LH model. The performance of LFO/PMS process was also estimated in the presence of various inorganic anions. The potential toxicity of LFO and PMS were evaluated using phytoplankton and the toxicity evolution during DCF degradation was also investigated using luminescent bacteria. This contribution provides a basic study regarding the potential application of heterogeneous PMS activation by perovskite LFO for both DCF removal and toxicity elimination. Highlights • The catalytic activity of LFO is contingent on the calcination temperature of LFO. • Diclofenac degradation rate depends on pH value, PMS and LFO dose. • The marginal effect of LFO dosage is larger than that of PMS concentration. • H 2 PO 4 − substantially inhibited DCF degradation. • Toxicity elimination of DCF can be achieved by LFO/PMS process. [ABSTRACT FROM AUTHOR]

Abstract Perovskite LaFeO 3 nanoparticles were successfully synthesized by microwave plasma method combined with high temperature calcination at 700–1000 °C. The influences of calcination temperature on morphology, crystalline structure, purity and the atomic compositions of samples were studied. The photocatalytic performance of LaFeO 3 was evaluated though the photodegradation of Rhodamine B (RhB) under visible light. In this research, the orthorhombic LaFeO 3 nanoparticles showed band gaps in the range of 2.15–2.30 eV. The particle size increased with increasing in the calcination temperature, leading to the decreasing in the surface area. The LaFeO 3 sample calcined at 900 °C showed the highest photodegradation of 77.8% and the apparent rate constant of 0.0077 min−1 within 180 min because of the narrower of band gap and the higher crystalline degree and oxygen adsorption. [ABSTRACT FROM AUTHOR]

Abstract Based on first-principles calculations, we investigated the hydrogen adsorption dissociation on the LaFeO 3 (010) surface with an O vacancy. It was confirmed that H 2 molecules have four kinds of adsorption modes on LaFeO 3 (010) surfaces with an O vacancy. First, H atoms are adsorbed on O atoms to form an OH group. Second, H atoms are adsorbed on Fe atoms to form Fe H bonds. Third, two H atoms are adsorbed on the same O atom to form H 2 O. Fourth, two H atoms are adsorbed on the same Fe atom and it is a new type of adsorption, which does not exist in the ideal surface. The main channel of dissociative adsorption is the fourth adsorption mode of OH and Fe H, where the H atoms adsorbed on the surface of Fe can be easily diffused into O atoms. Charge population analysis showed that increasing the O vacancy enhanced the interaction between Fe H. In the system containing O vacancies adsorbed H atoms in the top of Fe to diffuse to the top of O need to overcome the energy barrier decreased from 0.968 eV to 0.794 eV. So the existence of an O vacancy enhances the hydrogen absorption properties of Fe atoms in LaFeO 3. Highlights • The O vacancy is easily formed on the surface in the LaFeO 3 (010) surface system. • The adsorption modes of H 2 molecules on the LaFeO 3 (010) surface with O vacancy. • The presence of O vacancies improves the hydrogen absorption properties of the system. • H 2 molecule is adsorbed to form H 2 O ,which leads to re-defect on the crystal surface. [ABSTRACT FROM AUTHOR]

Abstract Using citrate sol-gel method, we prepared La 0.85 Mg 0.15- x Ba x FeO 3 (x = 0.02–0.12) samples. X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM) were used to investigate whether the microstructure, composition, and magnetic properties of LaFeO 3 were affected by the following parameters: calcination temperature, calcination time, and the doping concentration of Mg2+ ion and Ba2+ ions. The XRD spectra showed that a trace of impurity phase (MgFe 2 O 4) is visible when the content of Mg2+ ions was higher; however, there was no change in the orthorhombic perovskite structure of LaFeO 3 even at higher doping concentrations. The space group was still Pnma. No other phase was generated in the sample subjected to low-temperature calcination. Furthermore, FT-IR spectra confirmed the presence of some functional groups in the sample. Then, SEM showed that the size distribution of the particles is uniform in the sample, and the grain boundary is also clear. Finally, VSM measurements proved that the significant changes were produced in the magnetic properties of samples when they were doubly doped with Mg2+ and Ba2+ ions. Moreover, calcination temperature has a great influence on the magnetic properties of the samples. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A Z-scheme LaFeO 3 /SnS 2 hybrid was fabricated by simple hydrothermal method. • LaFeO 3 /SnS 2 exhibited boosted visible-light photocatalytic degradation for TC. • A plausible Z-scheme charge transfer mechanism was tentatively proposed. Abstract Visible-light-driven photocatalytic degradation of organic pollutants is considered as one of the promising and effective strategies for water purification. Extensive efforts have been devoted to explore various inorganic and organic semiconductor materials as photocatalysts for the degradation of organic pollutants under visible light irradiation in the past few decades. Among them, artificial Z-scheme photocatalyst has recently attracted considerable attention in water purification owing to it can not only effective transfer and separation of the photogenerated charge carriers, but also retain prominent redox ability. Herein, a direct Z-scheme LaFeO 3 /SnS 2 hybrid was successfully constructed via a facile hydrothermal method. The structure, composition, photoelectric and photocatalytic properties of the as-obtained samples were systematically characterized by X-ray diffraction, Fourier transform infrared spectrum, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, UV–Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, transient photocurrent response, electrochemical impedance spectroscopy and photocatalytic degradation of tetracycline (TC). These characterizations revealed that the LaFeO 3 nanoparticles were well dispersed on the surface of SnS 2 nanosheets. The photoelectrochemical characterizations demonstrated that the promoted transfer and separation of charge carrier in the LaFeO 3 /SnS 2 hybrid was achieved. As expected, compared to bare LaFeO 3 and SnS 2 , all the LaFeO 3 /SnS 2 hybrids displayed boosted the photocatalytic performances for the degradation of TC under visible light irradiation (λ > 420 nm). In particular, the photocatalytic degradation of TC over all the as-obtained samples obeyed pseudo-first-order kinetics equation, and the optimal photodegradation rate constant over the LaFeO 3 (10.0 wt%)/SnS 2 hybrid for TC degradation was up to 0.0028 min−1, which was about 3.5 and 2.2 times larger than those of SnS 2 and LaFeO 3 , respectively. Such an enhancement could be mainly ascribed to the formation of the Z-scheme LaFeO 3 /SnS 2 heterojunction, which not only promoted the visible light absorption, but also facilitated the charge separation and transfer efficiency and prolonged lifetime of charge carriers as a result of the closely contacted Z-scheme heterojunction interface effect between LaFeO 3 and SnS 2. Furthermore, results from the radical trapping experiments confirmed that there existed the Z-scheme charge transfer mechanism, and the synergistic effect of superoxide radicals and holes was favorable for the photodegradation of TC under visible light irradiation. This work will provide a new insight for the rational design and construction of highly efficient SnS 2 -based Z-scheme heterojunction hybrid photocatalysts for applying in environmental remediation and energy conversion. [ABSTRACT FROM AUTHOR]

Highlights • Pure and In-doped LaFeO 3 hollow nanofibers were successfully prepared via electrospinning. • In doping made the surface of LaFeO 3 nanofibers to be more rough and improved the gas-sensing properties. • The sensor based on In-doped LaFeO 3 hollow nanofibers presents high response to 1 ppm formaldehyde at 100 °C, and possess fast response/recovery time (3/3 s). Abstract Hollow nanofibers of pure and In-doped LaFeO 3 were fabricated via electrospinning followed by calcination and characterized by various techniques. The results indicated that In element was successfully doped in LaFeO 3 lattice and the surface roughness was increased with the increase of In content. The gas sensing test showed that the sensor based on In-doped LaFeO 3 hollow nanofibers exhibited high response value at the operating temperature of 100 °C with fast response/recovery time to formaldehyde, and the detection limited can be as lower as 1 ppm. Due to these excellent sensing performances, In-doped LaFeO3 hollow nanofibers could be an effective candidate for the fabrication of formaldehyde sensors. [ABSTRACT FROM AUTHOR]

Abstract Plasmonic Ni nanoparticles were incorporated into LaFeO 3 photocathode (LFO-Ni) to excite the surface plasmon resonances (SPR) for enhanced light harvesting for enhancing the photoelectrochemical (PEC) hydrogen evolution reaction. The nanostructured LFO photocathode was prepared by spray pyrolysis method and Ni nanoparticles were incorporated on to the photocathode by spin coating technique. The LFO-Ni photocathode demonstrated strong optical absorption and higher current density where the untreated LFO film exhibited a maximum photocurrent of 0.036 mA/cm2 at 0.6 V vs RHE, and when incorporating 2.84 mmol Ni nanoparticles the photocurrent density reached a maximum of 0.066 mA/cm2 at 0.6 V vs RHE due to the SPR effect. This subsequently led to enhanced hydrogen production, where more than double (2.64 times) the amount of hydrogen was generated compared to the untreated LFO photocathode. Ni nanoparticles were modelled using Finite Difference Time Domain (FDTD) analysis and the results showed optimal particle size in the range of 70–100 nm for Surface Plasmon Resonance (SPR) enhancement. Highlights • FTDT shows best particle size range for enhanced performance. • LaFeO 3 photocathode is synthesised by simple spray pyrolysis method. • Ni nanoparticles incorporated into LaFeO 3 photoacthode by spin coat method. • Ni nanoparticle enhances performance of photocathode by surface plasmon resonance. [ABSTRACT FROM AUTHOR]

Highlights • BaTiO 3 /LaFeO 3 nanocomposite was prepared by a citric sol-gel method. • Higher gas response to ethanol was obtained than pure LaFeO 3 nanoparticles. • Origin of improved ethanol sensing performance was analyzed by TEM, BET and XPS. Abstract BaTiO 3 /LaFeO 3 nanocomposite with BaTiO 3 and LaFeO 3 nanoparticles in the mole ratio of 1:2 was prepared by a citric sol-gel method and used as sensing materials to fabricate nanoparticle-based sensors. TEM, BET and XPS results suggested that the capability of absorbing oxygen species from air played the more important role than the grain size or specific surface area in the determination of gas sensing performance for nanoparticles. BaTiO 3 /LaFeO 3 sensor showed improved gas response towards ethanol with respect to the LaFeO 3 sensor at the expense of deteriorated dynamic response. Owing to the higher content of adsorbed oxygen species and ratio of Fe4+/Fe on the surface of the sensing material, better and stable sensing performance to ethanol was achieved by the BaTiO 3 /LaFeO 3 sensor at the prime working temperature of 128 °C, with a high gas response (102.7) to 100 ppm ethanol. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The highly efficient LaFeO 3 perovskite oxides were synthesized. • DFT calculations are conducted for PMS adsorption and electron transfer. • ATR-FTIR was used for in situ characterization of LFO surface during catalytic reaction. • Activation mechanisms of PMS by LFO were proposed. • Diclofenac degradation pathways were presented. Abstract A perovskite oxide, LaFeO 3 (LFO), was synthesized and evaluated as a heterogeneous catalyst to activate peroxymonosulfate (PMS) for the oxidative degradation of diclofenac (DCF), a non-steroidal anti-inflammatory drug. It was observed that the catalytic activity of LFO was much higher than that of Fe 2 O 3. LFO catalyzed PMS to degrade DCF with a turnover frequency (2.02 × 10−3 min−1) which is 17-fold higher than that of Fe 2 O 3. Both sulfate and hydroxyl radicals were identified during LFO-activated PMS process by electron spin resonance (ESR). Radical competitive reactions indicate sulfate radicals played a major role in DCF degradation by LFO/PMS process. The PMS decomposition can be attributed to the formation of an inner-sphere complexation between the Fe (III) sites on LFO surface and PMS. Theoretical calculations illustrated the strong interaction between PMS and Fe (III) and electron transfer from PMS to Fe (III). Hydrogen temperature-programmed reduction (H 2 -TPR) indicates that the LFO perovskite oxide is capable of facilitating an easier reduction of Fe (III) to mediate a redox process. Oxygen temperature-programmed desorption (O 2 -TPD) suggests much more oxygen vacancies exist in LFO than in Fe 2 O 3. Oxygen vacancies are favorable for the formation of chemical bond between Fe (III) and PMS and the activation of PMS. In situ ATR-FTIR analysis of LFO surface during PMS decomposition implies Fe (III)–Fe(II)–Fe (III) redox cycle was believed to account for the generation of sulfate radical. The intermediates generated during DCF degradation were identified and the possible degradation pathways were advanced in LFO/PMS system. [ABSTRACT FROM AUTHOR]