The increasing demand for advanced materials with multifunctional magnetic properties has sparked growing interest in rare-earth and transition metal-based double perovskites. In this study, we comprehensively investigate disordered Y2CoCrO6 (YCCO), synthesized via the sol-gel method. Structural analysis confirms a single-phase orthorhombic crystal structure with B-site disorder, as revealed by X-ray photoelectron spectroscopy, which also identifies mixed valence states of Co and Cr due to antisite disorder and oxygen vacancies. This structural disorder profoundly impacts YCCO ' s magnetic properties, leading to the emergence of a Griffiths-like phase, detected through inverse susceptibility measurements. Additionally, the material exhibits both antiferromagnetic and weak ferromagnetic behaviors, evidenced by a negative Curie-Weiss temperature and unsaturated magnetic hysteresis loops. Arrott plot analysis indicates a second-order phase transition and magnetocaloric measurements reveal a maximum entropy change (Smax) of 0.217 J kg-1 K-1, a relative cooling power (RCP) of 17.36 J kg-1, and a temperature averaged entropy change (TEC) of 0.17 J kg-1 K-1 over a temperature span (Tlift) of 30 K under a 5 T field, showcasing its potential for low-temperature and multistage cooling applications. Although its modest magnetocaloric effect (MCE) performance is attributed to its antiferromagnetic nature with weak ferromagnetic contributions and a low Curie temperature, this work represents a significant step in unveiling the potential of YCCO for multifunctional applications. Future optimization through chemical doping, nanostructuring, and compositional modifications is proposed to enhance its magnetocaloric and functional properties, positioning YCCO as a strong candidate for advanced magnetic and cooling technologies.

In this study, we present a comprehensive theoretical and experimental investigation into the electronic structure, optical properties, and photocatalytic potential of Gd2CoCrO6 (GCCO) double perovskite. Using first-principles calculations with the generalized-gradient-approximation plus Hubbard U (GGA + U) method, we explored the effects of Coulomb interactions on the electronic properties. Our calculations revealed that GCCO exhibits a half-metallic nature, displaying metallic behavior for up-spin and semiconducting behavior for down-spin states. The optimized U eff value of 4.2 eV accurately reproduces the direct bandgap of 2.25 eV, which aligns closely with experimental results obtained through UV-visible absorption spectroscopy and photoluminescence analysis. Additionally, time-resolved photoluminescence (TRPL) measurements indicate a mean charge carrier lifetime of 2.37 ns, suggesting effective charge separation. Mott-Schottky analysis and valence band X-ray photoelectron spectroscopy (XPS) confirm the n-type semiconducting nature of GCCO with favorable band edge positions for redox reactions. The combination of theoretical insights and experimental characterization indicates that GCCO holds significant promise as a photocatalyst for applications in renewable energy production and environmental remediation, particularly in solar-driven water splitting and pollutant degradation. Our study provides crucial insights into the electronic structure and optical properties of double perovskites like GCCO, highlighting their suitability for photocatalytic applications. Furthermore, the research paves the way for future work in the compositional engineering and defect modulation of double perovskites to optimize their photocatalytic efficiency.

A facile sol-gel synthesis method was employed to synthesize dysprosium chromite (DyCrO3) nanoparticles (NPs), which were subsequently calcined at 750 degrees C to investigate their structural, optical, and photocatalytic properties. Rietveld refinement of powder X-ray diffraction patterns revealed a single-phase orthorhombic structure for the DyCrO3 NPs, exhibiting good crystallinity and belonging to the Pbnm space group. Furthermore, Field Emission Scanning Electron Microscopy and Transmission Electron Microscopy imaging revealed a promising morphology with an average particle size of 30 +/- 7 nm. Optical assessments indicated an energy band gap of 2.72 eV, suggesting potential for solar light harvesting as a photocatalyst. Mott-Schottky plots confirmed the n-type semiconductor behavior of the DyCrO3 NPs, and valence band X-ray photoelectron spectroscopy analysis supported these findings. Electronic band structure calculations showed a substantial conduction band minimum and a positive valence band maximum, essential for promoting oxygen reduction and oxidation reactions, respectively, which are crucial for photocatalytic activity. Moreover, the synthesized DyCrO3 NPs demonstrated significant potential as efficient photocatalysts, effectively decomposing the antibiotic ciprofloxacin (CIP) under solar light. Notably, the DyCrO3 NPs achieved 83 % degradation of CIP within 240 min of solar irradiation. Similarly, under identical conditions, the DyCrO3 NPs photocatalyst showed promise in degrading 70 % of the colored organic pollutant methylene blue (MB). Interestingly, during the first 120 min, the degradation of CIP was approximately 25 % greater than that of MB. The ability of DyCrO3 NPs to efficiently degrade both colored and colorless pollutants highlights the catalyst's inherent photocatalytic nature, rather than merely relying on dye-sensitization effects. Furthermore, the presence of DyCrO3 NPs reduced the activation energy for CIP degradation from 31.657 kJ mol- 1 K- 1 to 20.846 kJ mol- 1 K-1, providing additional evidence of their true catalytic efficacy. Apparent quantum yield values of 40 % for CIP and 35 % for MB degradation further illustrate their superior solar energy harvesting ability. A comprehensive mechanism was developed to explain the impressive photocatalytic performance of the synthesized NPs, highlighting their potential in degrading pharmaceutical antibiotics.

In this study, DyFeO3-MoS2 heterojunction nanocomposites were synthesized by integrating porous DyFeO3 nanoparticles (an n-type semiconductor) with MoS2 nanosheets (a p-type semiconductor). The resulting p-n heterojunction substantially improved the photocatalytic efficiency for degrading methylene blue (MB) and levofloxacin (LFX). This design introduces a built-in electric field at the interface, promoting efficient charge separation and suppressing electron-hole recombination, thereby significantly enhancing photocatalytic performance under solar irradiation compared to DyFeO3 alone. Characterization studies, including XRD, FESEM, TEM, XPS, UV-visible absorbance, photoluminescence, and Mott-Schottky analysis, confirmed the nanocomposites' crystalline structure, well-dispersed MoS2 nanosheets, oxygen vacancies, enhanced visible light absorption, and favorable band positions. The incorporation of MoS2 increased light absorption, enhanced charge separation, and improved surface area by mitigating DyFeO3 aggregation, leading to significantly higher photocatalytic degradation rates. Among the tested compositions, the DyFeO3-MoS2 (80 : 20) nanocomposite, containing 20 wt% MoS2, exhibited the highest efficiencies, with 96.5% degradation for MB and 88.7% for LFX. Further analyses, including activation energy determination, quantum yield measurement, scavenger tests, and reusability assessments, confirmed the optimized nanocomposite's performance and durability. The reduced activation energies and high quantum yields (35.5% for MB, 25.8% for LFX) indicate efficient photon conversion and radical generation, with superoxide radicals (˙O2-) identified as the primary reactive species. Stability tests revealed over 85% retention of activity after four cycles, underscoring the composite's robustness. Moreover, the photocatalytic mechanism revealed key insights into the degradation pathways of pollutants. This investigation demonstrates a viable solar-driven solution for efficient pollutant degradation in wastewater treatment by incorporating MoS2 into porous DyFeO3 nanostructures.

Aqueous supercapacitors (SCs) encounter limitations in operational voltage and energy density due to the low decomposition voltage of water. Here, we fabricate aqueous symmetric supercapacitors (ASSCs) employing DyFeO3 as an electrode material. This hybrid SC in a 0.5 M Na2SO4 aqueous electrolyte exhibits a significantly high working voltage of 2.5 V, with an energy density of 41.81 W h kg-1 at a power density of 1250 W kg-1, maintaining 94% capacitance retention after 5000 cycles. By incorporating 20% volume of acetonitrile with water in the electrolyte, we extend the potential window to 3.1 V, with an energy density of 84.43 W h kg-1 at a power density of 1550 W kg-1. The as-fabricated ASSC shows promising stability during a 300-hour float voltage test with almost intact capacitance retention and Coulombic efficiency. For the first time, our study unveils the potential of porous DyFeO3 as an electrode material for advancing ASSCs, featuring an unprecedented ultra-wide voltage window, along with significantly large energy and power densities.

In this investigation, nanoparticles of B-site disordered Y2NiCrO6 (YNCO) double perovskite were synthesized by the facile sol-gel method to evaluate their magnetic and electrochemical properties. Their crystallographic structure is monoclinic and the average size of the particles is 79 +/- 16 nm. XPS analysis indicated a mixed oxidation states of B-site transition metals Ni2+/Ni3+ and Cr2+/Cr3+. The mixed valence states of Ni and Cr, along with the mixed magnetic phases of YNCO, constitute a signature of the B-site disorder. This antisite disorder contributed to the observation of a Griffiths-like phase arising from ferromagnetic short-range interactions above the magnetic transition up to the Griffiths temperature, T-G = 137 K. The synthesized YNCO double perovskite demonstrated a promising behavior as an electrode material for electrochemical supercapacitors. In a three-electrode system, it displayed a specific capacitance of 270 F g(-1) at a current density of 0.5 A g(-1). In a symmetric two-electrode system, YNCO exhibited a specific capacitance of 180 F g-1 at 0.5 A g(-1), alongside an energy density of 6.25 Wh kg(-1) at 250 W kg(-1) power density. In both cases, we employed a mild 0.5 M neutral aqueous Na2SO4 solution as the electrolyte, in contrast to the typically employed corrosive and concentrated alkaline aqueous solution. The fascinating magnetic and charge storage properties of the B-site disordered YNCO double perovskite indicate its potential for use in spintronic devices and as efficient electrodes in symmetric hybrid supercapacitors.

Understanding the authentic nature and stability of a photocatalyst through diverse experiments and calculations is crucial for advancing environmental remediation. In this study, we synthesized nano-sized DyFeO3 particles with a porous structure, featuring an average pore size of 40 nm, to meticulously evaluate their photocatalytic efficacy in degrading aquatic pollutants under solar irradia- tion. These nanoparticles exhibit a direct band gap of 2.1 eV, rendering them well-suited for effective solar light absorption. Additionally, the conduction band minimum suggests potential participation in reduction reactions, while the valence band maximum is conducive to oxidation reactions. To confirm the authentic catalytic efficiency of DyFeO3 photocatalysts, we assessed their ability to de- grade both colored Rhodamine B (RhB) and colorless antibiotic Levofloxacin (LFX). Notably, their photocatalytic performance in decomposing the colorless pollutant LFX, alongside the colored RhB, eliminates any potential influence of dye sensitization. Moreover, the presence of DyFeO3 in the solution medium decreased the activation energy of LFX degradation from 38.4 kJ mol-1 K-1 to 34.1 kJ mol-1 K-1 , providing further evidence of their true catalytic function. Furthermore, their apparent Quantum Yield values of 28.94% and 32.83% for RhB and LFX degradation, respectively, demon- strate superior solar energy harvesting capability compared to commercially available TiO2. The high degradation efficiency, high quantum yield, and excellent stability of single-structured DyFeO3 nanoparticles indicate their considerable potential for large-scale production in photocatalytic and related applications.

Understanding the authentic nature and stability of a photocatalyst through diverse experiments and calculations is crucial for advancing environmental remediation. In this study, we synthesized nano-sized DyFeO3 particles with a porous structure, featuring an average pore size of 40 nm, to meticulously evaluate their photocatalytic efficacy in degrading aquatic pollutants under solar irradiation. These nanoparticles exhibit a direct band gap of 2.1 eV, rendering them well-suited for effective solar light absorption. Additionally, the conduction band minimum (CBM) suggests potential participation in reduction reactions, while the valence band maximum (VBM) is conducive to oxidation reactions. To confirm the authentic catalytic efficiency of DyFeO3 photocatalysts, we assessed their ability to degrade both colored Rhodamine B (RhB) and colorless antibiotic Levofloxacin (LFX). Notably, their photocatalytic performance in decomposing the colorless pollutant LFX, alongside the colored RhB, eliminates any potential influence of dye sensitization. Moreover, the presence of DyFeO3 in the solution medium decreased the activation energy of LFX degradation from 38.4 kJ mol-1 1 K-1 to 34.1 kJ mol-1 K-1 , providing further evidence of their true catalytic function. Furthermore, their apparent Quantum Yield (AQY) values of 28.94% and 32.83% for RhB and LFX degradation, respectively, demonstrate superior solar energy harvesting capability compared to commercially available TiO2. The high degradation efficiency, high quantum yield, and excellent stability of single-structured DyFeO3 nanoparticles indicate their considerable potential for large-scale production in photocatalytic and related applications

Aqueous supercapacitors (SCs) encounter limitations in operational voltage and energy density due to the low decomposition voltage of water. Here, we fabricate aqueous symmetric supercapacitors (ASSCs) employing DyFeO3 as an electrode material. This hybrid SC in a 0.5 M Na2SO4 aqueous electrolyte exhibits a significantly high working voltage of 2.5 V, with an energy density of 41.81 W h kg-1 at a power density of 1250 W kg-1, maintaining 94% capacitance retention after 5000 cycles. By incorporating 20% volume of acetonitrile with water in the electrolyte, we extend the potential window to 3.1 V, with an energy density of 84.43 W h kg-1 at a power density of 1550 W kg-1. The as-fabricated ASSC shows promising stability during a 300-hour float voltage test with almost intact capacitance retention and Coulombic efficiency. For the first time, our study unveils the potential of porous DyFeO3 as an electrode material for advancing ASSCs, featuring an unprecedented ultra-wide voltage window, along with significantly large energy and power densities.

In this investigation, BiFeO3 (BFO) and 10% La-doped BiFeO3 (BLFO) nanoceramics were synthesized by a sol–gel method for the photocatalytic degradation of colorless antibiotics ciprofloxacin and levofloxacin under the irradiation of 500 W Hg-Xe lamp. A good agreement between the structural transitions from rhombohedral to orthorhombic phase was observed by the X-ray diffraction and the vibrational modes in the Raman spectra, due to the substitution of Bi by La. Moreover, La doping resulted in a decrease in the particle size from ∼117 to 32 nm, reduction of oxygen vacancies, significant enhancement of magnetization, dramatic improvement of optical absorption, and reduction of band gap from 2.19 to 2.14 eV. The significantly enhanced magnetization might be associated with the suppression of the spiral spin cycloid of BFO due to the substitution of La and reduced size of the BLFO nanoceramics to ∼32 nm which was also confirmed by transmission electron microscopy imaging. The strong optical absorption of BLFO nanoceramics boosted their photo-generated charge carriers separation, produced more reactive species, and demonstrated ∼70% photocatalytic efficiency to degrade pharmaceutical pollutants from aqueous solution. The high saturation magnetization and strong optical absorption mostly in the visible region suggest the potentiality of BLFO nanoceramics as a promising photocatalyst with a superior recyclability to be magnetically extracted from the reaction medium.

Understanding the authentic nature and stability of a photocatalyst through diverse experiments and calculations is crucial for advancing environmental remediation. In this study, we synthesized nano-sized DyFeO3 particles with a porous structure, featuring an average pore size of 40 nm, to meticulously evaluate their photocatalytic efficacy in degrading aquatic pollutants under solar irradiation. These nanoparticles exhibit a direct band gap of 2.1 eV, rendering them well-suited for effective solar light absorption. Additionally, the conduction band minimum (CBM) suggests potential participation in reduction reactions, while the valence band maximum (VBM) is conducive to oxidation reactions. To confirm the authentic catalytic efficiency of DyFeO3 photocatalysts, we assessed their ability to degrade both colored Rhodamine B (RhB) and colorless antibiotic Levofloxacin (LFX). Notably, their photocatalytic performance in decomposing the colorless pollutant LFX, alongside the colored RhB, eliminates any potential influence of dye sensitization. Moreover, the presence of DyFeO3 in the solution medium decreased the activation energy of LFX degradation from 38.4 kJ mol-1 1 K-1 to 34.1 kJ mol-1 K-1 , providing further evidence of their true catalytic function. Furthermore, their apparent Quantum Yield (AQY) values of 28.94% and 32.83% for RhB and LFX degradation, respectively, demonstrate superior solar energy harvesting capability compared to commercially available TiO2. The high degradation efficiency, high quantum yield, and excellent stability of single-structured DyFeO3 nanoparticles indicate their considerable potential for large-scale production in photocatalytic and related applications

The persistent issue of water contamination by industrial dyes and pharmaceutical residues has created an urgent need for advanced photocatalytic materials to effectively address environmental remediation. Despite ongoing research, developing novel photocatalysts with ideal band structures, high quantum yields, and strong stability remains a considerable challenge. In this study, we report the synthesis and detailed characterization of nanostructured dysprosium orthoferrite (DyFeO3) nanoparticles, designed with a porous architecture featuring an average pore size of 3.41 nm and a surface area of 23.25 m(2) g(-1) to enhance photocatalytic efficiency under solar irradiation. Using Inverse Fast Fourier Transform (FFT) analysis on selected areas of TEM images, we gained deeper insights into the formation and internal structure of these nanoparticles. DyFeO3 nanoparticles exhibit a direct band gap of 2.1 eV, making them particularly effective for solar light absorption. Comprehensive spectroscopic analyses, including Mott-Schottky measurements and valence band XPS, confirmed their n-type semiconducting nature and revealed an electronic band structure that supports efficient oxygen reduction and oxidation reactions. Additionally, time-resolved photoluminescence spectroscopy demonstrated a charge carrier lifetime of 2.43 ns, indicating efficient separation and transport of photogenerated charge carriers. The photocatalytic performance of DyFeO3 was evaluated through degradation experiments using two model pollutants: Rhodamine B (RhB) and Levofloxacin (LFX). The nanoparticles successfully degraded both the colored RhB and the colorless LFX, eliminating concerns of dye sensitization. Furthermore, the presence of DyFeO3 significantly reduced the activation energy for RhB degradation from 55.87 kJ mol(-1) K-1 to 34.58 kJ mol(-1) K-1 and for LFX from 38.4 kJ mol(-1) K-1 to 34.1 kJ mol(-1) K-1, demonstrating its catalytic efficiency. With apparent quantum yield values of 28.94% for RhB and 32.83% for LFX, these nanoparticles demonstrate exceptional solar energy harvesting capabilities. The high degradation efficiency, quantum yield, and stability of the single-structured DyFeO3 nanoparticles highlight their potential for large-scale applications in photocatalytic and environmental remediation technologies.

Aqueous supercapacitors (SCs) are often constrained by low operational voltage and energy density due to the low decomposition voltage of water. In this work, we address these limitations by fabricating symmetric SCs using nanoporous dysprosium orthoferrite (DyFeO3) electrodes in dilute, neutral aqueous electrolytes. The nanoporous architecture of the DyFeO3 electrode material, with an average pore size of 3.41 nm, was confirmed using Brunauer-Emmett-Teller analysis and comprehensively characterized through XRD, FESEM, TEM, XPS, Raman spectroscopy, EPR, and zeta potential measurements. The fabricated SC, operating in a 0.5 M Na2SO4 aqueous electrolyte, exhibited a high working voltage of 2.5 V, delivering an energy density of 41.81 W h kg-1 at a power density of 1250 W kg-1, with 90% capacitance retention after 10 000 cycles. Furthermore, the addition of 20% acetonitrile (AN) to the 0.5 M Na2SO4 electrolyte extended the potential window to 3.1 V, increasing the energy density to 84.43 W h kg-1 at a power density of 1550 W kg-1. The fabricated symmetric SC demonstrated excellent long-term stability, retaining approximately 99% capacitance and Coulombic efficiency after a 600 hours float voltage test. These findings, for the first time, reveal the potential of nanoporous DyFeO3 as electrode material in a 0.5 M Na2SO4(aq.)/20%AN electrolyte for advancing symmetric SCs, featuring an unprecedented ultra-wide electrochemical stability window along with significantly enhanced energy and power densities.

In this investigation, moisture-stable CsSnBr2Cl nanoparticles were synthesized by incorporating Cl into CsSnBr3 halide perovskite using the hot injection method. Various analyses including XRD, XPS, UV-vis absorbance, photoluminescence, and Mott-Schottky have confirmed that the structural properties, chemical states, optical properties, and electronic band structure of CsSnBr2Cl nanoparticles remain intact even after 75 days of water immersion, thereby conclusively demonstrating their moisture stability. In a three-electrode system, the comparative electrochemical performance of pristine CsSnBr3 nanoparticles and moisture-stable Cl-incorporated CsSnBr2Cl nanoparticles was evaluated in various aqueous electrolytes, including HCl, Na2SO4, and KOH. The results indicate that the CsSnBr2Cl electrode material exhibits superior electrochemical properties, such as a larger integrated cyclic voltammetry (CV) area, a wider potential window, longer charge-discharge times, and lower impedance parameters compared to the pristine CsSnBr3 nanoparticles. The electrochemical performance of CsSnBr2Cl nanoparticles was evaluated for potential applications in batteries, supercapacitors, fuel cells, and water splitting, with a focus on reaction kinetics, charge storage mechanisms, and impedance parameters. The electrochemical properties of the nanoparticles were assessed using a three-electrode configuration across various 0.5 M aqueous electrolytes (HCl, Na2SO4, and KOH). In HCl, the nanoparticles demonstrated impressive charge storage capability, achieving a capacitance of 474 F g(-1) at 1 A g(-1), affirming their suitability for energy storage devices. In Na2SO4(aq.), the nanoparticles exhibited excellent stability for supercapacitors, operating up to 1.6 V without significant oxygen evolution. Notably, in KOH, they demonstrated potential as effective water-splitting electrodes. The practical applicability of the nanoparticles was evaluated using a symmetric two-electrode configuration with HCl and Na2SO4 electrolytes. The capacitance values were 117 F g(-1) in HCl and 70 F g(-1) in Na2SO4 at 1 A g(-1). Notably, after 5000 GCD cycles in HCl(aq.), the nanoparticles retained 93% of their capacitance and maintained 91% Coulombic efficiency. They also demonstrated stable operation across a temperature range of 3 to 60 degrees C, achieving an energy density of 5.83 W h kg(-1) at a power density of 600 W kg(-1). This study emphasizes the considerable potential of CsSnBr2Cl nanoparticles in advancing electrochemical energy storage technologies and sets a solid foundation for future research and development in metal halide perovskites.

A comprehensive comparison between sillenite and perovskite phases of Bi 0.9 Dy 0.1 FeO 3 (BDFO) nanostructures synthesized by hydrothermal (HT) and sol–gel (SG) techniques.

Disordered double perovskite Gd 2 CoCrO 6 nanoparticles (average size 71 ± 3 nm) with fascinating magnetic and optical properties were synthesized that might be promising for photocatalytic and related solar energy applications.

In this present investigation, nanoparticles of B-site disordered Y2FeCrO6 (YFCO) double perovskite have been successfully synthesized for the first time by optimizing synthesis steps and temperatures of facile sol -gel technique to investigate their structural, magnetic, and optical properties. The Rietveld refinement of the X-ray diffraction pattern of YFCO nanoparticles revealed a single-phase orthorhombic structure with pbnm space group. The average size of the nanoparticles is around 67 +/- 15 nm determined by both field emission scanning electron microscopy and transmission electron microscopy imaging. The existence of mixed valence states of Fe and Cr ions was confirmed by X-ray photoelectron spectroscopy which is an indication of the absence of proper B site long range ordering. The temperature dependent magnetization curves demonstrated negative magnetization of this double perovskite material with compensation tem-perature at around 170 K. The field-dependent magnetic hysteresis loops exhibited the coexistence of weak ferromagnetic and antiferromagnetic domains in YFCO nanoparticles. The exchange bias effect was ob-served below Neel temperature which is tunable by a cooling magnetic field. The UV-visible spectroscopy ensured that YFCO nanoparticles have a direct band gap of similar to 1.90 eV, which was further confirmed by steady-state photoluminescence spectroscopy. This B-site disordered YFCO might enhance interest on basic fundamental research on disordered rare-earth and transition metal-based perovskite systems and can be used for spintronics as well as photocatalytic applications because of its favorable magnetic and optical properties.(c) 2023 Elsevier B.V. All rights reserved.

Substitution of Sn by Bi in CsSnBr3 led to a more stable cubic perovskite structure. It also causes a significant decrease in the size of the nanocrystals from 316 ± 93 to 87 ± 22 nm and improvement in photocatalytic performance.