Mn Precursor Research Articles

Electrodeposited Zn-Mn on three-dimensional electrodes as anodes in liquid and quasi-solid-state zinc-air batteries

Zinc-air batteries (ZABs) are eco-friendly and sustainable energy storage devices. There are different challenges to overcome in ZABs, where anodic issues such as shape changes, passivation, self-corrosion, and dendrite formation require urgent solutions. In this work, Zn and Zn-Mn alloys were electrodeposited on three-dimensional porous carbon electrodes varying the Mn composition (2, 20 and 40 g L−1) and studying its effect during the operation of a 6 M KOH liquid ZAB and a quasi-solid-state ZAB based on poly(vinyl alcohol)/poly(acrylic acid) PVA/PAA gel polymer electrolyte (GPE). Scanning electron microscopy (SEM) images indicated that Zn and Zn-Mn were deposited as platelet-like bi-dimensional structures. Additionally, the use of 20 and 40 g L−1 of the Mn precursor resulted in larger Zn deposition covering the 3D structure of the carbon paper. Elemental analysis indicated that the Mn content in Zn-Mn was 1.3, 2.4 and 6 %. In the aqueous ZAB, the Zn-Mn with 2.4 % Mn enabled to increase the maximum current density achieving the highest power density of 45 mW cm⁻2. In QSS-ZAB, Zn-Mn at 1.3 and 2.4. % Mn displayed higher stability to recovery after demanding different current densities, while the first anode displayed higher cyclability, presenting a similar round trip after 240 charge/discharge cycles This ZAB was maintained functional during 290 cycles vs. 120 cycles for Zn foil. The rechargeability was improved because of the decrease in Zn dendritic growth and passivation.

Tailored Core-Shell Nanostructure Achieved through Atomic Layer Deposition for Superior Energy Storage Performance Application

A distinctive method was employed to construct ultrathin NiO on phosphorous-doped MnO2 nanosheets, utilizing a straightforward hydrothermal process to form a Mn precursor on Ni-foam followed by phosphorous doping through a simple solid-state annealing process and ALD technique. The impact of phosphorous doping was examined by varying the annealing temperature, resulting in a significant increase in oxygen vacancies and electrochemical performance. Additionally, the atomic layer deposition of NiO not only improved electrochemical performance but also ensured cycling stability without impeding the system. By adjusting the thickness of the NiO thin films over phosphorous-doped MnO2, a notable enhancement in electrochemical performance was achieved, as evidenced by the performance of the solid-state asymmetric device. This hybrid approach is expected to pave the way for novel electrode material designs for high-performance supercapacitors, leveraging electroactive metal oxides through ALD coating.

Influence of Mn precursor on pre-pyrolysis modification of sugarcane bagasse biochar for enhanced removal of 2,4-dichlorophenoxyacetic acid from aqueous solutions: Experimental and theoretical insights

Biochars impregnated with Mn oxides were produced using sugarcane bagasse (SB) modified with MnCl2 (Mn(II)-BC) or KMnO4 (Mn(VII)-BC) for the removal of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) through adsorption. The composites were structurally and functionally characterized by various techniques, revealing an irregular surface with oxide microspheres. Elemental analyses showed the presence of manganese and oxygen in distinct proportions. X-ray diffraction identified crystalline planes of MnO and Mn3O4, as well as the amorphous carbon phase. Infrared spectroscopy confirmed Mn bonded to oxygen, and its influence on BC graphitization was corroborated by Raman spectroscopy. Thermogravimetry highlighted the oxides' influence on thermal stability, while the total number of acidic and basic functions revealed notable differences in surface chemistry. Adsorptive removal of 2,4-D was optimized under conditions of pH 2.00, dosage of 2 g L−1, and particle size smaller than 100 mesh. Adsorption equilibrium was attained after 24 and 12 hours for Mn(II)-BC and Mn(VII)-BC, respectively, with experimental maximum capacities of 36.78 and 57.19 mg g−1. Freundlich and Sips isotherms fit better for Mn(II)-BC and Mn(VII)-BC, respectively, while Elovich and pseudo-second-order kinetic models were suitable. Density Functional Theory (DFT) calculations confirm that, with decreasing pH, hydrogen bonding takes place. At higher pH,binding with Mn3O4 suggests efficacy in Mn(II)-BC composite adsorption, not observed in Mn(VII)-BC due to an additional oxide, differentiating available sites. Despite Mn leaching challenges, post-acid exposure reuse showed favorable removal percentages, indicating potential for reutilization. These findings confirm the suitability of the synthesized composites as adsorbents for the remediation of water contaminated with 2,4-D.

Enhancing the Red Fluorescence of Carbon Dots: The Role of Mn Doping and Precursor Concentration Control

Enhancing the Red Fluorescence of Carbon Dots: The Role of Mn Doping and Precursor Concentration Control

Mn derived growth of CsPbBr3 nanoplatelets for stable and bright orange emission

Abstract Mn-doped perovskites have been extensively studied in optics, magnetism, and electronics due to their orange emission. However, successful Mn doping required a high Mn/Pb feed ratio. In this paper, Mn-doped CsPbBr3 nanoplatelets (NPLs) with bright orange emission were prepared by a two-step slow thermal injection synthesis. The slow injection of precursors effectively slow-down the crystal growth kinetic process and controls the growth of undoped CsPbBr3 NPLs. This process also significantly improves Mn doping efficiency. Mn doping induced the generation of numerous precursor clusters during the growth of CsPbBr3 NPLs, and the formation of these clusters was crucial for enhancing the doping efficiency. The maximum amount of Mn precursor in CsPb0.83Mn0.17Br3 was 50% of Pb precursors. The photoluminescence quantum yields (PLQYs) of CsPb0.94Mn0.06Br3 NPLs reached up to 80.6%, which was 3.1 times of that of CsPbBr3 NPLs. The PL properties of Mn-doped CsPbBr3 NPLs were significantly enhanced compared with pure CsPbBr3 NPLs. The growth process and luminescence mechanism of Mn-doped CsPbBr3 NPLs were discussed. High PLQYs and efficient Mn doping supplied an ideal approach for the preparation of various CsPbX3 (X = Cl, Br, and I) NCs for commercial applications.

Investigation the optical and structural properties of Mn-doped Sb2S3 nanocrystals embedded in host glass

The search for earth-abundant and non-toxic elements is essential for the manufacture of sustainable optical devices. In this context, dilute magnetic semiconductor (DMS) xMn-doped Sb2S3 nanocrystals (NCs) embedded in host glass were synthesized by the fusion method. Differential Thermal Analysis shows evidence of Sb2S3 phase crystallization peak and changes in glass transition and crystallization temperatures of the host glass with the presence of xMn-doped Sb2S3 NCs. Transmission electron microscopy images show the formation of xMn-doped Sb2S3 NCs with increasing size (2.1–3.8 nm) as a function of concentration (x = 0.00 to 0.40), respectively. X-ray diffraction measurements reinforced the evidence for the orthorhombic structure of xMn-doped Sb2S3 NCs embedded in glass. Energy dispersive X-ray spectroscopy analyses confirm the S, Sb and Mn precursor elements of DMS NCs. Atomic and magnetic force microscopy measurements show the magnetic contrast patterns resulting from the incorporation of Mn atoms into the Sb2S3 structure. The electronic paramagnetic resonance spectrum confirms the presence of Mn2+ ions (3d5) located in the crystal field of the Sb2S3 semiconductor due to six hyperfine transitions. The redshift of the Raman vibrational mode (1Ag) with increasing xMn concentration gives strong evidence for the presence of Mn2+ ions in sulfur vacancies (VS) in the Sb2S3 unit cell. Optical absorption and photoluminescence (PL) spectroscopy measurements for xMn-doped Sb2S3 NCs show the subtle tunable redshift of the band gap and excitonic recombination in the green-red region, with increasing x concentration. PL confirms that dopant Mn2+ ions fill VS2 that are dominant in Sb2S3. Therefore, the position of the energy states after the increasing concentration of Mn2+ dopant ions gives rise to insight into luminescence for future research scenarios and applications involving sustainable DMS NCs.

Evaluation of the effect of precursor ratios on the electrochemical performances of binder-free NiMn-phosphate electrodes for supercapattery

Binary metal phosphate electrodes have been widely studied for energy storage applications due to the synergistic effects of two different transition elements that able to provide better conductivity and stability. Herein, the battery-type binder-free nickel-manganese phosphate (NiMn-phosphate) electrodes were fabricated with different Ni:Mn precursor ratios via microwave-assisted hydrothermal technique for 5 min at 90 °C. Overall, NiMn3P electrode (Ni:Mn = 1:3) showed an outstanding electrochemical performance, displaying the highest specific (areal) capacity at 3 A/g of 1262.4 C/g (0.44 C/cm2), and the smallest charge transfer resistance of 108.8 Ω. The enhanced performance of NiMn3P electrode can be ascribed to the fully grown amorphous nature and small-sized flake and flower structures of NiMn3P electrode material on the nickel foam (NF) surface. This configuration offered a higher number of active sites and a larger exposed area, facilitating efficient electrochemical reactions with the electrolyte. Consequently, the NiMn3P//AC electrode combination was chosen to further investigate its performance in supercapattery. The NiMn3P//AC supercapattery exhibited remarkable energy density of 105.4 Wh/kg and excellent cyclic stability with 84.7% retention after 3000 cycles. These findings underscored the superior electrochemical performance of the battery-type binder-free NiMn3P electrode, and highlight its potential for enhancing the overall performance of supercapattery.

Metal ratio and bimetal nanoarchitectonics of ammonia-based fluoride complex induced nickel hydroxide and manganese oxide composites as active materials of an energy storage device

Nickel and manganese compounds are widely applied as efficient battery-type active materials for energy storage devices, due to high theoretical capacities and abundant redox states for generating redox reactions to store charges. Morphology plays significant roles on energy storage ability. Structure directing agent (SDA) is widely reported to have ability for modulating configurations of active materials and to achieve excellent surface properties. In this work, it is the first time to use NH4BF4 and NH4HF2 as structure directing agents for synthesizing nickel manganese compounds derived from ZIF67 as active materials of energy storage devices. Bimetallic compounds are composed of nickel hydroxide and manganese oxide, which presents the favorable two-dimensional flower-like structure with high surface area and abundant redox states. The largest specific capacitance (CF) of 1358.2 F/g corresponding to the capacity of 226.4 mAh/g are achieved for the bimetallic compound synthesized using the Ni to Mn precursor ratio of 1 to 1 (NiMn11). The energy storage device assembled using NiMn11 and reduced graphene oxide on Ni foams presents a maximum energy density of 11.45 Wh/kg at the power density of 0.35 kW/kg, and excellent long-term stability with the CF retention of 85.6% and Coulombic efficiency of 87.5% after 10,000 cycles.

Fabrication, characterization, photocatalytic and biological performances of Mn/ZnO–SiO2 and ZnO–SiO2/PVA based ternary nanocomposites

Abstract Different strategies can be employed to enhance and adjust the overall characteristics and potential applications of the nanomaterials. Herein, ZnO–SiO2, Mn/ZnO–SiO2 and ZnO–SiO2/PVA based nanocomposites were synthesized by sol-gel and in-situ polymerization methods by taking the Zn(CH3COO)·2H2O as ZnO, TEOS as the SiO2 and Mn(SO4)2·7H2O as the Mn precursors. The present study investigates various aspects of ZnO–SiO2, Mn/ZnO–SiO2, and ZnO–SiO2/PVA nanomaterials, including electronic transition, surface morphology, elemental composition, chemical structure elucidation, thermal stability, and phase changes. To accomplish this, several techniques were employed. All the results confirmed the formation of the synthesized composite materials. Moreover, the catalytic and photocatalytic activities of the synthesized composites were studied through the degradation of Methylene blue (MB) dye, etc. The results confirmed that the synthesized nanocomposites exhibited good catalytic and photocatalytic activities towards removal of methylene blue (MB) dye removal. Further, the catalytic/photocatalytic activity of ZnO–SiO2, Mn/ZnO–SiO2 and ZnO–SiO2/PVA nanocomposites were also compared towards the removal of methylene blue (MB) dye and it was verified that the Mn/ZnO–SiO2 nanocomposite show high photocatalytic activity among the three nanocomposites i.e., ZnO–SiO2, Mn/ZnO–SiO2 and ZnO–SiO2/PVA with removal efficiencies of 81 %, 77 % and 77 %, after 6 h, 5 h and 9 h respectively, under UV light illumination. Moreover, the photodegradation mechanism was also studied and finally, the biological activities like antioxidant and antileishmanial were also studied and compared.

Insights into the photocatalytic role of glycine-assisted sol-gel auto-combustion synthesized (Co, Mn)(Co, Mn)2O4 nanostructures for efficient visible light-driven degradation of methyl orange

Research on the use of new materials and the improvement of existing fast ways for removal of water pollutants is still challenging. This work documented rational fabrication of (Co, Mn)(Co, Mn)2O4 nanoparticles as nano-photocatalyst materials with improved charge carrier separation and strong redox potential for efficient degradation of methyl orange (MO) in wastewater. This investigation illustrated that the Co/Mn molar ratio can greatly affect the textural and structural properties. From the point of view of size and shape, the optimum product with 1:3 M ratio of Co to Mn precursors was selected as a catalyst in the photocatalysis process. The prepared highly crystallized phase of tetragonal (Co, Mn)(Co, Mn)2O4 describe an optical band gap of 1.7 eV, according to the DRS data, which make them as efficient visible driven photocatalysts. The photodegradation experiments of spinel mixed structures were assessed by investigation of photocatalyst dosages and initial MO concentrations to unravel how these operational parameters affect Co-Mn-O photocatalysis. A remarkable discoloration capability of 68.07 % could result from the catalyst dosage of 0.04 g and dye concentration of 15 mg/L after 120 min of visible light. The kinetics survey further unveiled the maximum rate constant of 0.0080 min−1 for the MO degradation. In the scavenger trials, singlet oxygen (1O2) and superoxide (●O2−) radicals were principal reactive oxygen species (ROS) responsible for pollutant photodegradation in the presence of pure (Co, Mn)(Co, Mn)2O4 structures. In addition, the cyclic performance of catalyst depicted a removal efficiency of 60.1 % over 5 runs.

Hydrothermal Synthesis of MnO2 Microspheres and Their Degradation of Toluene.

Various urchin-like MnO2 materials were obtained with a facile hydrothermal method through controlling the Mn precursor, reaction time, and reaction temperature. The property of MnO2 materials was characterized by scanning electron microscopy, X-ray diffraction, and H2 temperature-programmed reduction. The results showed that the Mn precursor could significantly impact the morphology of as-prepared MnO2. When the precursor was Mn(CH3COO)2·4H2O, the MnO2 morphology consisted of tennis-like microspheres assembled by nanorods. While the precursor was MnCl2·4H2O, the sample morphology was a chestnut shell, and the samples were sea urchin microspheres, as the precursor was MnSO4·H2O. At the same time, the morphology of MnO2 was affected by hydrothermal time and temperature. The nanoneedles on the microsphere surface gradually lengthened with increasing hydrothermal time and hydrothermal temperature, until nanowires were formed. MnO2 crystallinity was also influenced by hydrothermal temperature. It was γ-MnO2 as the temperature was 50 and 80 °C while evolved to be α-MnO2 and β-MnO2 when the temperature increased to 140 °C. As MnO2 (MnO2-1 h, MnO2-2 h, MnO2-4 h, and MnO2-6 h) was prepared to degrade toluene, all the samples could completely catalyze toluene at the temperature of 225 °C. However, the MnO2-4 h showed the best catalytic effect at a lower temperature.

Sustainable recovery of LiCoO2 from spent lithium-ion batteries: Simplicity, scalability, and superior electrochemical performance

In light of the ecological ramifications and material consumption stemming from exhausted lithium-ion batteries, an exigent requirement persists for efficient and expansible recycling techniques. Herein, we investigate an innovative expedited method to directly regenerate and enhance spent LiCoO2 (SLCO). The profoundly discharged SLCO powders, featuring an unimpaired crystal lattice, are isolated. These powders are then amalgamated with Li, Ni, and Mn precursors. Subsequent heating at elevated temperatures yields LNMO-SLCO, effecting the direct regeneration of LCO, accompanied by a synergistic re-lithiation process and the application of a LiNi0.5Mn1.5O4 (LNMO) coating, all achieved in a single step. The homogeneously thin spinel LNMO coating layer (10–15 nm) bestows upon LNMO-SLCO an enhanced cycling performance and charge–discharge rate capacity when benchmarked against SLCO and commercial LiCoO2 (CLCO). Evidently, at 0.1C, 0.5C, and 2C rates, LNMO-SLCO delivers discharge capacities of 214.4 mAh g−1, 187.4 mAh g−1, and 144.1 mAh g−1, respectively. Notably, it sustains 77.68 % of its original capacity following 100 cycles at 0.5 C. The merits of LNMO-SLCO are corroborated through cyclic voltammetry and electrochemical impedance spectroscopy, affirming its reduced charge transfer resistance and augmented lithium-ion solid phase diffusion coefficient. This endeavor stands as the foremost documented instance of a direct approach to SLCO reconstruction involving LNMO coating, culminating in the formation of LNMO-SLCO, characterized by sustained high-voltage cycling performance. The outlined re-lithiation and LNMO coating stratagem proffer valuable insights for the scalable, high-value recycling of SLCO, while remaining transposable to other spent cathode materials.

Tuned bimetallic MOFs with balanced adsorption and non-radical oxidizing activities for efficient removal of arsenite

The removal of arsenic from contaminated water is important for environmental protection and drinking water safety worldwide. In this study, bimetallic metal–organic frameworks (MOFs) with catalytic and adsorptive effects were synthesized and combined with peroxymonosulfate (PMS) for efficient As(III) oxidation and As(III)/As(V) removal. The molar ratio of Fe and Mn precursor was adjusted to balance the adsorption and catalytic processes of As(III) in the system. The results showed that among the Fe/Mn-MOFs and MIL-88(Fe) tested, the Fe/Mn-MOFs with an Fe/Mn molar ratio of 1:1 (Fe0.3Mn0.3-MOFs) could achieve the best catalytic and adsorption performance with 98% removal of As(III). The performance of Fe0.3Mn0.3-MOFs in natural contaminated water was also verified. Electron spin resonance detection and quenching experiments have revealed that trivalent arsenic oxidation is facilitated primarily by a non-radical process through singlet oxygen. Density-functional theory, XPS and FTIR analyses reveal the structures, corresponding binding energies and binding sites for the adsorption of As(III)/As(V) by Fe0.3Mn0.3-MOFs. The coupling of Fe0.3Mn0.3-MOFs to the PMS system was still able to achieve 78% arsenic removal after five cycles, showing good reliability and effectiveness in arsenic removal. This study provides a new insight into the catalytic and adsorption mechanisms in MOFs/PMS systems and provides a theoretical basis for the application of MOFs in the remediation of arsenic contaminated water.

Ni2+‐Assisted Dealloying Strategy to Prepare Nanoporous Cu–Ni Alloys with Enhanced Corrosion Resistance

To address the challenges associated with preparation of nanoporous Cu–Ni (NP‐CuNi) alloys containing high Ni concentrations, a Ni2+‐assisted dealloying strategy is proposed. The proposed strategy involves a three‐stage dealloying process primarily driven by dynamic Ni deposition/dissolution. The Ni concentration in NP‐CuNi is tuned by altering the Ni content of the Cu–Mn precursor alloy and Ni2+ in a H2SO4 solution. The Ni concentration of the nanoporous Cu66.5Ni28.5Mn5 alloy prepared in a H2SO4 + NiSO4 solution is increased by 5.2 times compared to that of the alloy prepared in the H2SO4 solution alone. Moreover, the corrosion resistance test demonstrates a reduction in corrosion current density by 58.3% compared to NP‐Cu.

Catalytic oxidation of toluene over highly dispersed Mn-Ce solid solutions synthesized with weakly acidic precursors

In this paper, a series of Mn-Ce composite oxide catalysts were prepared by different preparation methods using different Mn and Ce acidic precursors for the catalytic oxidation of toluene. The activity test results revealed that the Mn-Ce composite catalysts, synthesized through the sol-gel method using weakly acidic Mn acetate and Ce acetate as precursors, exhibited the highest performance for the catalytic oxidation of toluene. The T50 and T90 values for this catalyst were measured at 208 °C and 235 °C, respectively. The relatively weak acidity of manganese acetate and cerium acetate facilitates the presence of acidic -OH groups, which interact with the oxygen-negative charge sites on each other. Furthermore, during the calcination process, there was a strong interaction between hydrated Mn and Ce ions, resulting in the formation of highly dispersed metal oxide species. The formation of Mn-Ce solid solution demonstrated by Raman, XRD. The H2-TPR characterization indicated that the superior redox performance of the MnOx species on the catalyst surface played a pivotal role in achieving high activity. Moreover, the catalytic activity of the CeO2 species was further enhanced by employing the sol-gel method. XPS and O2-TPD results revealed a significantly higher amount of reactive oxygen species on the catalyst surface, which was identified as the primary reason for the increased activity. This study provides a new strategy for the selection of the catalyst precursors, thereby enhancing the catalytic activity of Mn-Ce composite oxides.

Mn/O co-doped Bi2S3 bimetal oxysulfide catalyst for highly efficient reduction of organic and hexavalent chromium pollutants in the dark

Mn and O co-doped Bi2S3 (labeled as BiMnOS) catalyst was synthesized using different amounts of Mn precursor (MnCl2.4H2O) by a simple and feasible method and characterized by various techniques. The doped Mn and O improve the energy band structure and morphology, reduce the charge transfer resistance, increase the electrochemically active surface sites, and the heterovalent Mn3+/Mn2+ states in Mn/O–Bi2S3 enhances the electron lifetime and facilitates fast electron transfer, which accelerates the pollutants reduction reaction. The BiMnOS-3 at n(Mn): n(Bi): n(C2H5NS) = 4: 1: 4 has the best-reducing properties. 10 mg BiMnOS-3 ultimately reduced the 20 ppm 100 mL 4-aminophenol (4-NP) solution in the presence of NaBH4 within 14 min, and the reduction rate constant of 0.3514 min−1 was 12.5 times that of BiOS and 11.7 times that of MnOS. The reduction reactions of methyl orange (MO), methylene blue (MB), Rhodamine B (RhB), and Cr (VI) were also completed within 8, 10, 28, and 24 min, respectively. The catalytic activity of BiMnOS-3 remained above 90.6% after 6 repeated tests for the reduction of 4-NP, which showed good cycling stability. Therefore, this study verified that the suitable ratio of the metal precursors plays a vital role in designing novel, efficient, and synergistically defect-attired bimetal oxysulfide catalysts.

Structural, electronic, and magnetic properties of MnSi and Mn4Si7 nanowires

The importance of nanoscale magnetism under tailored phase evolution has been gaining considerable interest in the past few decades, attributable to the surging demand for memory devices and emerging electromagnetism. Herein, we present experimental demonstrations and theoretical studies on the structural, electronic, and magnetic properties of MnSi and Mn4Si7 nanowires grown by thermal chemical vapor deposition. The crystallinity of the nanowires was confirmed by a high-resolution transmission electron microscope and elemental distribution. The ratio of Mn to Si (∼0.96–1.04) indicates uniformity in MnSi composition. Additionally, the Mn4Si7 nanowire has an Mn/Si ratio of ∼0.78–0.87, which deviates from the homogenous Mn4Si7 ratio of ∼ 0.6 due to a higher Mn content at the nucleation sites. We found that the MnSi nanowires remained ferromagnetic (FM), similar to bulk MnSi, whereas the Mn4Si7 nanowires exhibited an FM order in contrast to the non-magnetic nature of bulk Mn4Si7. Field-cooled and zero-field-cooled magnetization curves reveal that the Mn4Si7 nanowires exhibited an FM order with a transition temperature (Tc) above room temperature. In contrast, the MnSi nanowires have a lower Tc of ∼ 30 K. It is noting that the First-principles density functional theory calculations demonstrated that both MnSi and Mn4Si7 nanowires possess a metallic characteristic. The spin-charge density of Mn4Si7 nanowires was found to be localized near the surface, implying a surface-induced magnetism. These findings suggest the possibility of tunning the phase evolution of Si-based nanowires by simply changing the diffusion mechanism of the Mn precursor. These metallic nanowires may be used as nanoscale interconnects and gate electrodes in nanoscale technologies.

Facile Method to Create PdCe–MnOx Catalyst for Decomposing O3 under Humidity Conditions

Manganese oxides are one of the most promising candidates for ambient decomposition of O3. However, catalysts with high efficiency require complicated preparation processes to cultivate active microstructures. This study developed a simple and easy to scale up method to produce catalysts via thermal annealing of Mn precursor. With slight addition of Ce and Pd, the obtained PdCe–MnOx catalyst exhibited excellent O3 removal activity in the presence of water vapor. Numerous characterization methods, including X-ray diffraction, high-resolution transmission electron microscopy, mapping, Brunauer–Emmett–Teller, H2-temperature-programmed reduction, O2-temperature-programmed desorption, X-ray photoelectron spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy, were applied to explore the relationship between activity and structure. The slight addition of Pd and Ce not only boosts the formation of surface vacancy species but also enhances the water vapor resistance, all of which contribute to its excellent ozone decomposition performance.

Role variations of MnOx on monoclinic BiVO4 (110)/(040) facets for enhanced Photo-Fenton reactions

Compared with traditional Fenton reaction, peroxymonosulfate based advanced oxidation processes (PMS-AOPs) are more effective to remove the organic pollutants in wastewater in a wider pH range. Herein, selective loading of MnOx on monoclinic BiVO4 (110) or (040) facets were achieved by photo-deposition method with addition of different Mn precursors and electron/hole trapping agents. MnOx has good chemical catalysis activity for PMS activation, which can also enhance photogenerated charge separation, thus leading to enhanced activities than naked BiVO4. The BPA degradation reaction rate constants of MnOx(040)/BiVO4 and MnOx(110)/BiVO4 system are 0.245 min−1 and 0.116 min−1, which are 6.45 and 3.05 times larger than that of naked BiVO4, respectively. The roles of MnOx on different facets are different, which will promote OER process on (110) facets and utilize the dissolved O2 to produce O2•− and 1O2 more effectively on (040) facets. 1O2 is the dominated reactive oxidation species of MnOx(040)/BiVO4, while SO4•− and •OH play more important roles on MnOx(110)/BiVO4, which are proved by quenching experiments and chemical probe identifications, thus mechanism in MnOx/BiVO4-PMS-light system is proposed. The good degradation performance of MnOx(110)/BiVO4 and MnOx(040)/BiVO4 and mechanism theory may promote the application of photocatalysis in PMS based wastewater remediation.

Lead-Free, Luminescent Perovskite Nanocrystals Obtained through Ambient Condition Synthesis.

Heterovalently substituting toxic lead is an increasingly popular design strategy to obtain environmentally sustainable variants of the exciting material class of halide perovskites. Perovskite nanocrystals (NCs) obtained through solution-based methods exhibit exceedingly high optical quality. Unfortunately, most of these synthesis routes still require reaction under inert gas and at very high temperatures. Herein a novel synthesis routine for lead-free double perovskite (LFDP) NCs is presented. An approach based upon the hot injection and ligand-assisted reprecipitation (LARP) methods to achieve a low-temperature and ambient atmosphere-based synthesis for manganese-doped Cs2 NaBiCl6 NCs is presented. Mn incorporation is critical for the otherwise non-emissive material, with a 9:1 Bi:Mn precursor ratio maximizing the bright orange photoluminescence (PL) and quantum yield (QY). Higher synthesis temperatures slightly increase the material's performance, yet NCs synthesized at room temperature are still emissive, highlighting the versatility of the synthetic approach. While the material's indirect bandgap limits its appeal for optoelectronics, this feature could benefit photocatalysis due to longer carrier lifetimes. Moreover, the developed synthesis is facile and can rapidly be adapted to other more viable material compositions and up-scaled to realize applications directly.