Excellent Catalytic Performance Research Articles

The crucial role of interaction between WOx and Ti–Si composite oxide for selective hydrogenolysis of glycerol to 1,3-propanediol

Hydrogenolysis of glycerol, a by-product in the preparation of biodiesel, to synthesize 1,3-propanediol has attracted widespread attention because of its environmental and economic benefits. How to activate the secondary hydroxyl group in glycerol to suppress the formation of 1,2-propanediol is still challenging. Pt-WOx-based catalyst has been popularly studied due to high 1,3-propanediol selectivity but its stability is unsatisfactory. Here we synthesized an oxygen vacancy-rich support (HTSO) consisting of Ti–Si composite oxide to stabilize WOx species. The glycerol conversion and 1,3-propanediol selectivity of optimized 2Pt-10WOx/HTSO-1.0 catalyst achieved 40% and 46%, respectively. Moreover, the catalytic performance remained stable over 10 reaction cycles. Based on the investigation of the structure-performance relationship of catalysts, the excellent catalytic performance was attributed to the anchoring of WOx species by oxygen vacancies, thus stabilizing the chemical valence of W. The correlation between acid sites and catalyst performance was intensively investigated. This work provides an alternative approach for preparing stable Pt-WOx-based catalysts and deepens the knowledge of the correlation between acidic sites and 1,3-propanediol selectivity.

Controllable fabrication of N-doped carbon nanotubes coated Co4N nanoparticles to boost hydrogen evolution reaction

Transition metal nitrides (TMNs) have attracted great attention as ideal active materials in the field of electrocatalysts in recent years due to their excellent electrical conductivity, wide band gap and adjustable morphology. Pure phase Co4N nanoparticles encapsulated nitrogen-doped carbon (NC) nanotubes (Co4N@NC) were in-situ synthesized by one-pot method. In this paper, the morphology of carbon nanotubes is controlled by adjusting the pyrolysis time, so that more active sites are exposed on carbon nanotubes. Thus, the cobalt nitride catalyst with excellent catalytic performance for hydrogen evolution reaction (HER) in acidic electrolyte was obtained. In summary, due to the protection of mesoporous nitrogen-doped carbon to Co4N nanoparticles, large electrochemically active surface area, good conductivity and more exposed active sites, Co4N@NC possesses excellent HER performance in acidic electrolytes. The overpotential of Co4N@NC at the current density of 10 mA cm−2 is 117 mV (η10), and it shows long-term stability in 0.5 M H2SO4 solution for 50 h. This study provides a strategy for the development of catalysts for the controllable synthesis of high-performance transition metal nitrides.

A novel graphene oxide electrode preparation and its performance in the treatment of saline organic wastewater

This study uses electrochemical technology to simultaneously remove salt and degrade organic pollutants to achieve green and efficient treatment of high-salt organic wastewater. In this study, graphene oxide (GO), which has excellent conductivity, chemical stability, and catalytic adsorption performance, was selected to prepare a composite electrode, aiming to explore its performance and evaluate its possibility of being used for the degradation of high-salt phenol wastewater treatment. The samples were characterized using SEM, FTIR, and other techniques. The electrochemical performance of the samples was analyzed using an electrochemical workstation, and their practical application performance was explored through simulated wastewater experiments. Experimental results confirmed that among the three electrodes prepared, the CFGE exhibited the lowest system energy consumption and the highest current efficiency, measuring 235.81 kWh/kgCOD and 12.66 % respectively. The HGE electrode is second only to it, with 269.39 kWh/kgCOD and 11.08 % respectively. The SCGE electrode has the worst performance, which is 344.83 kWh/kgCOD and 8.66 % respectively. The Yst of the three electrodes are 0.4083 mg/L∙min, 0.3817 mg/L∙min, and 0.29 mg/L∙min respectively. This study provides new research ideas and solutions for the efficient treatment of high-salt organic wastewater.

Earth-abundant Zn-dipyrrin chromophores for efficient CO2 photoreduction.

The development of strong sensitizing and Earth-abundant antenna molecules is highly desirable for CO2 reduction through artificial photosynthesis. Herein, a library of Zn-dipyrrin complexes (Z-1-Z-6) are rationally designed via precisely controlling their molecular configuration to optimize strong sensitizing Earth-abundant photosensitizers. Upon visible-light excitation, their special geometry enables intramolecular charge transfer to induce a charge-transfer state, which was first demonstrated to accept electrons from electron donors. The resulting long-lived reduced photosensitizer was confirmed to trigger consecutive intermolecular electron transfers for boosting CO2-to-CO conversion. Remarkably, the Earth-abundant catalytic system with Z-6 and Fe-catalyst exhibits outstanding performance with a turnover number of >20 000 and 29.7% quantum yield, representing excellent catalytic performance among the molecular catalytic systems and highly superior to that of noble-metal photosensitizer Ir(ppy)2(bpy)+ under similar conditions. Experimental and theoretical investigations comprehensively unveil the structure-activity relationship, opening up a new horizon for the development of Earth-abundant strong sensitizing chromophores for boosting artificial photosynthesis.

Recent Progress on the Surface and Bulk Modification of Carbon Nitrides for Photocatalytic Carbon Dioxide Reduction

Photocatalytic CO2 reduction has been considered as a green and sustainable approach to solve energy and environmental problems. However, the CO2 reduction efficiency of various types of semiconductor photocatalysts studied at this stage is far from realizing practical applications. The challenge of photocatalytic CO2 reduction is to design photocatalysts with excellent catalytic performance. This article summarizes the carbon nitride materials for efficient CO2 reduction and obtaining high value‐added products. The physicochemical properties of carbon nitride materials are discussed in terms of the photocatalytic mechanisms (bandgap tuning, high specific surface area, shorter electron–hole transmission paths, increasing the number of active sites, etc.). The present review provides the latest research progress of carbon nitride modification strategies. The prospects and challenges for the application of carbon nitride materials for CO2 reduction are presented. This review article will provide useful guidance for further research on carbon nitride materials for efficient photocatalytic CO2 reduction.

Rational Design and Synthesis of Fe-Doped Co-Based Coordination Polymer Composite Photocatalysts for the Degradation of Norfloxacin and Ciprofloxacin.

The solar light-responsive Fe-doped Co-based coordination polymer (Fe@Co-CP) photocatalyst was synthesized under mild conditions. [Co(4-padpe)(1,3-BDC)]n (Co-CP) was first constructed using mixed ligands through the hydrothermal method. Then, Fe was introduced into the Co-CP framework to achieve the enhanced photocatalytic activity. The optimal Fe@Co-CP-2 exhibited excellent catalytic degradation performance for norfloxacin and ciprofloxacin under sunlight irradiation without auxiliary oxidants, and the degradation rates were 91.25 and 92.66% in 120 min. These excellent photocatalytic properties were ascribed to the generation of the Fe-O bond, which not only enhanced the light absorption intensity but also accelerated the separation efficiency of electrons and holes, and hence significantly improved the photocatalytic property of the composites. Meanwhile, Fe@Co-CP-2 displayed excellent stability and reusability. In addition, the degradation pathways and intermediates of antibiotic molecules were effectively analyzed. The free radical scavenging experiment and ESR results confirmed that •OH, •O2-, and h+ active species were involved in the catalytic degradation reaction; the corresponding mechanisms were deeply investigated. This study provides a fresh approach for constructing Fe-doped Co-CP-based composite materials as photocatalysts for degradation of antibiotic contaminants.

Efficient catalytic ozonation for hexazinone degradation by Fe/Ce-doped MOF derivatives

High catalytic efficiency and strong anti-interference catalyst for refractory pollutants removal remains a challenge for the catalytic ozonation. Metal-organic framework (MOF) have shown excellent performance in catalysis filed, but there is a risk of metal ion leaching. Designing MOF derivatives by high temperature modulation is considered to be an effective way to enhance the performance and reduce leaching risk of MOFs. In this paper, Fe/Ce bimetallic metal–organic framework (FeCe-MOF) was synthesized and three MOF derivatives were prepared by calcination at different temperatures. The performance of MOF derivatives in the degradation of hexazinone via catalytic ozonation and the effects were investigated. The mechanism of catalytic ozonation by FeCe@C-600 was also elucidated by the analysis of structural characterization of the fresh and used FeCe@C-600, electron paramagnetic resonance (EPR) and quenching experiment. FeCe@C-600/O3 system achieved 78.78 % removal of hexazinone and 42.37 % degradation of TOC within 20 min. During the catalytic ozonation, FeCe@C-600 has high structural stability and avoiding the release of metal ions. FeCe@C-600 showed excellent performance to degrade and mineralize of hexazinone, and it is more stable and has wider pH applicability. The electron transfer and redox cycling of Mn+/Mn+1 were promoted along with the conversion of lattice oxygen to oxygen vacancies. The degradation of hexazinone was mainly attributed to the generation of reactive oxygen species (•OH, •O2–, 1O2) during catalytic ozonation. MOF derivatives exhibited good adsorption capacity during the degradation of hexazinone. FeCe@C-600 effectively reduces metal leaching while retaining high catalytic activity, providing new ideas for the development of new efficient and environmentally friendly ozone catalysts.

Construction of multi-porous Ni-based monolithic catalyst by combining wood carbon and SBA-15 for strengthening CO2 methanation

Monolithic catalysts meet the needs of practical application compared with powder catalysts. In this work, we constructed a Ni-based monolithic catalyst (Ni/SAB-15/WWC) by in situ growth of rod-like mesoporous SBA-15 in the microchannels of wood carbon. The small Ni-based nanoparticles (∼5.3 nm) were uniformly dispersed into the mesoporous channels via a post-loading method. The monolithic Ni/SAB-15/WWC catalyst with a multilevel porous structure could provide a laminar gas flow on the surface of Ni active sites, increasing the low-temperature activity and high-temperature durability of CO2 methanation. The Ni/SAB-15/WWC with low Ni loading (∼2%) displayed superior CO2 methanation catalytic performance in terms of low-temperature activity and CH4 selectivity compared with the powder Ni/SAB-15 with high Ni loading (∼15 %). The combination of wood carbon and mesoporous materials is an innovative strategy for the design monolithic catalysts with low metal loading and excellent catalytic performance.

Uncovering the discharge structure evolution and electrochemical performance of sulfur cathode host 2D-Fe0.89M0.11S2 (M = Ti, V)

The sulfur cathode host materials with excellent electronic conductivity and catalytic performance are the key to highly efficient Li-S redox chemistry for the lithium‑sulfur batteries (LSBs). Although 2D-FeS2 as sulfur cathode host shows high theoretical capacity and flat voltage plateaus, the Li-S redox chemical reaction mechanism is still unclear. By using the first-principles calculations, the formation energy, working voltage, theoretical capacity, electronic conductivity, adsorption performance, electrocatalytic mechanism, Li+ diffusion and Li2S decomposition barrier of 2D-FeS2 and M (M = Ti, V) doped 2D-FeS2 are investigated to evaluate its physicochemical properties. 2D-Fe0.89M0.11S2 is thermodynamically stable due to its low lattice distortion, formation energy and mixing enthalpy. The charging voltage of 2D-Fe0.89Ti0.11S2 is better than that of 2D-Fe0.89V0.11S2, but the charging voltage step is reversed. The electrical conductivity of 2D-Fe0.89M0.11S2 is superior to 2D-FeS2. The closer the highest molecule occupied orbitals is to the Fermi level, the lower the discharge voltage will be. 2D-Fe0.89V0.11S2 and its discharge structure 2D-Li2Fe0.89V0.11S2 improve the efficiency of catalytic reduction of Li2S4. 2D-Fe0.89V0.11S2 has low Li+ diffusion and decomposition barrier of Li2S, which has potential application value in promoting the Li-S redox chemistry. This work deepens the understanding of the doping strategy and provides theoretical guidance for the design and development of sulfur cathode host to improve the Li-S redox chemistry.

Preparation of Fe/P co-doped MMoO4 (M=Co, Cu and Zn) as environmentally friendly oxygen evolution reaction electrocatalyst

Hydrogen production from electrolyzed water has become an ideal new energy source for people to replace traditional fossil energy sources due to its high efficiency and low-carbon characteristics. Therefore, this paper presents preparation of a series of Fe/P co-doped MMoO4 (M=Co, Cu and Zn) catalyst loaded on nickel foam by simple hydrothermal and phosphorization process for the first time. After comparing different molybdate metal salts as precursors, it was demonstrated that the fabricated Fe/P co-doped CuMoO4 target catalysts possessed excellent catalytic performance with an overpotential of only 287 mV at a current density of 100 mA cm−2, faster reaction kinetics and a large active surface area for oxygen evolution reaction (OER). Density functional theory (DFT) calculation shows that the absorption energy of water and the electrical conductivity of the material are enhanced by the co-doping of the Fe and P. The doping of the Fe and P changes the electronic state and coordination environment of the active site, thus enhancing the catalytic activity of the electrode. The experimental results further prove that the doping of the Fe and P makes the active site more exposed and the resistance smaller, thus enhancing the conductivity and activation energy of the material. What is noteworthy is that the electrode also performed well in stability tests, which provided a fabrication solution of new catalyst for green hydrogen production.

A Co-Reactive Immunosensor Based on Ti3C2Tx MXene@TiO2-MoS2 Hybrids Promoting luminol@Au@Ni-Co NCs Electrochemiluminescence for CYFRA 21-1 Detection.

The construction of assays is capable of accurately detecting cytokeratin-19 (CYFRA 21-1), which is critical for the rapid diagnosis of nonsmall cell lung cancer. In this work, a novel electrochemiluminescence (ECL) immunosensor based on the co-reaction promotion of luminol@Au@Ni-Co nanocages (NCs) as ECL probe by Ti3C2Tx MXene@TiO2-MoS2 hybrids as co-reaction accelerator was proposed to detect CYFRA 21-1. Ni-Co NCs, as a derivative of Prussian blue analogs, can be loaded with large quantities of Au NPs, luminol, and CYFRA 21-1 secondary antibodies due to their high specific surface area. To further improve the sensitivity of the developed ECL immunosensor, Ti3C2Tx MXene@TiO2-MoS2 hybrids were prepared by in situ growth of TiO2 nanosheets on highly conductive Ti3C2Tx MXene, and MoS2 was homogeneously grown on Ti3C2Tx MXene@TiO2 surfaces by the hydrothermal method. Ti3C2Tx MXene@TiO2-MoS2 hybrids possess excellent catalytic performance on the electro-redox of H2O2 generating more O2·- and obtaining optimal ECL intensity of the luminol/H2O2 system. Under the appropriate experimental conditions, the quantitative detection range of CYFRA 21-1 was from 0.1 pg mL-1 to 100 ng mL-1, and the limit of detection (LOD) was 0.046 pg mL-1. The present sensor has a lower LOD with a wider linear range, which provides a new analytical assay for the early diagnosis of small-cell-type lung cancer labels.

Ultrasonic in-situ reduction preparation of SBA-15 loaded ultrafine RuCo alloy catalysts for efficient hydrogen storage of various LOHCs

SBA-15-loaded RuCo alloy nanoparticle catalysts (RuxCoy/S15-SU) for the efficient catalysis of hydrogen storage by various liquid organic hydrogen carriers (LOHCs) were prepared via strong electrostatic adsorption (SEA)-ultrasonic in-situ reduction (UR) technology. The above prepared catalysts were subjected to a series of characterization, such as XPS, H2-TPD/TPR, N2 adsorption–desorption, ICP, CO-chemisorption, FT-IR, XRD and TEM. Ru3+ and Co2+ were evenly anchored on the surface of SBA-15 by SEA, and ultrafine RuCo alloy nanoparticles were formed by UR without any chemical reducing or stabilizing agents. The addition of Co enhanced the dispersion and antioxidant capacity of the RuCo alloy NPs with an average particle size of 2.07 nm and increased the number of catalytically active sites. The synergistic effect of ultrafine particle size and electron transfer between Co and Ru improved the catalytic performance of monobenzyltoluene (MBT) for hydrogen storage. SEA-UR technology strengthened the coordination effect between RuCo alloy NPs and Si-OH, which enhanced the catalytic stability. H2-TPD and H2-TPR indicated that the addition of Co led to more activated H2 to produce hydrogen overflow. For the hydrogenation of MBT, the produced Ru2Co1/S15-SU showed excellent catalytic performance. The hydrogen storage efficiency of MBT was 99.98 % under 110 °C and 6 MPa H2 for 26 min, and the TOF was 145 min−1, which is significantly superior to that of Ru/S15-SU catalyst and that reported in the literature. The hydrogen storage efficiency was still as high as 99.7 % after ten cycles, which was much better than that of Ru/S15-SU and commercial 5 wt% Ru/Al2O3. Ru2Co1/S15-SU is also suitable for efficiently catalyzing hydrogen storage of N-ethylcarbazole, dibenzyltoluene and acenaphthene.

Synergistic catalysis of Ru0-Ru3+ in MOF supported ultrafine Ru nanoparticles catalyst promotes ethyl levulinate to γ-valerolactone

Synthesis of bifunctional catalysts is very important for the hydrogenation of biomass to advanced biofuels, but its efficient regulation is difficult. In this work, a tunable bifunctional Ru/LaQS catalyst with Lewis acid and metal hydrogenation sites was prepared by stable MOFs (LaQS) supported ultrafine Ru nanoparticles (NPs). When the optimal Ru2/LaQS catalyst catalyzed bio-based ethyl levulinate (EL) to γ-valerolactone (GVL), the EL conversion and GVL selectivity reached 99.9% under mild conditions of 100 °C. The excellent catalytic performance is mainly attributed to the synergistic effect of Ru0-Ru3+ on ultrafine Ru NPs with only 1.60 nm generated by metal-support interaction, which is proved by experimental characterization and theoretical calculation. Moreover, the electron density of hydrogenation active site Ru0 and the content of acidic site Ru3+ can be modulated by Ru loading. Among them, the activation of H2 was promoted by the high electron density of Ru0 generated through metal-support electronic interactions. The enhanced medium-strong acidic site Ru3+ not only improved the activation of EL, but also promoted the intramolecular dealcoholization of the intermediate to GVL. The synergistic catalytic mechanism of Ru0-Ru3+ on ultrafine Ru NPs was speculated. The excellent stability was mainly attributed to the metal-support interaction stabilizing the ultrafine Ru NPs, which prevents the agglomeration and loss of Ru NPs during cycling. This work provides an in-depth understanding of the bifunctional catalytic mechanism, which is of guiding significance for the design and preparation of MOFs-based catalysts for biomass hydrogenation.

Enhanced bifunctional oxygen electrochemical catalytic performance using La-doped CoFe2O4 spinel supported by 3D-G for Zn-air batteries

The preparation of bifunctional catalysts for oxygen reduction (ORR) and oxygen evolution (OER) is crucial for Zn-air batteries. Here, we report a La doped CoFe2O4 spinel catalyst supported on three-dimensional graphene (3D-G), where La can facilitate electron transfer from Co to Fe, leading to increased electron cloud density in Fe and improved catalytic performance. The redshift of the G peak in the Raman spectra indicates the interaction between the π bond of 3D-G and d orbitals in La0.2CoFe1.8O4. La0.2CoFe1.8/3D-G exhibits superior ORR performance (E1/2 = 0.86 V vs. RHE) and OER performance (Ej=10 = 1.55 V vs. RHE) to CoFe2O4/3D-G (E1/2 = 0.831 V vs. RHE, Ej=10 = 1.603 V vs. RHE). Furthermore, it demonstrates excellent bifunctional oxygen catalytic performance while maintaining high power density and stability in liquid zinc-air batteries (ZABs) and flexible ZABs (F-ZABs). This work presents a viable strategy for utilizing rare earth element doped spinels to enhance oxygen catalyst and ZABs performance.

Zeolitic Pickering Emulsifier with Intrinsic Amphiphilicity.

The formation of oil-in-water Pickering emulsions stabilized by lamellar zeolite MWW (International Zeolite Association, three-letters code) emulsifier without surface grafting is investigated. The crucial emulsification factors are the oligolayer morphology and amphiphilicity developed upon acidic treatment (NH4+ exchange/calcination, HNO3 treatment). In contrast with the readily available/abundant hydrophilic ≡Si-OH group in layer MWW, the lipophilicity generated by strong acid sites is another key to the success of emulsification. Hydrocarbon-strong acid site interaction is long known in petrochemistry and superacid research. However, to the best of our knowledge, this interaction was first introduced to gain lipophilicity in emulsion formation. Finally, the Pd-loaded acidic form of the MWW zeolite successfully stabilized the toluene/H2O emulsion system. The biphasic interfacial nitroarene hydrogenation demonstrated excellent catalytic performance. Overall, this work provided not only a new kind of intrinsic solid to emulsify the organic-aqueous biphase system but also a new mechanism to generate lipophilicity. Both are important for the applications and designs of Pickering emulsion materials.

Soft-templating synthesis of hierarchical mordenite as high-performance catalyst for cyclic acetals production via acetylation of glycerol and benzaldehyde

Highly active hierarchical mordenite zeolite with micro/mesoporosity (TM-n) for selective synthesis of cyclic acetals via acetylation reaction is reported. The hierarchical zeolite is synthesized using soft-templating approach with variations in octadecyltrimethoxysilane (OTMS/Al2O3 ratio, n = 0.2, 0.3 and 0.4) in precursor hydrogels. The results reveal that OTMS not only creates secondary mesoporosity in zeolite framework (larger mesopore volume, external surface area, average pore diameter), but also influences the crystallization process, altering the crystal morphology, crystallinity and Si/Al ratios. Among TM-n zeolites prepared, TM-0.3 hierarchical mordenite has the optimum OTMS amount incorporated while further increasing the OTMS amount leads to the formation of ANA/GIS intergrowth. Thanks to the accessible hierarchical porosity, reduced acidity and morphological effects, the TM-0.3 hierarchical mordenite exhibits excellent catalytic performance (84.1% conversion, TOF = 0.087 s−1, 61.5% dioxolane selectivity) in acetylation of glycerol and benzaldehyde (160 °C, 20 min) better than pristine mordenite. The catalyst is reusable for five runs with minimal loss of activity (TOF = 0.087 → 0.084 s−1), making it a promising catalyst for chemical productions involving bulky molecules. In addition, comparative catalytic tests with classical homogeneous and heterogeneous catalysts, including H2SO4, HCl, CH3COOH, H–Y, H-LTL, Na-X, Na-A, were performed.

Enhancement of low-temperature activity of γ-Fe2O3-modified V2O5-MoO3/TiO2 catalysts for selective catalytic reduction of NOx with NH3

In this study, a series of γ-Fe2O3-modified V2O5-MoO3/TiO2 (VMT) catalysts was prepared by wet impregnation method. The γ-Fe2O3-modified catalysts exhibited excellent catalytic performance, and 1.25 wt% γ-Fe2O3 content improved the deNOx efficiency at 150 °C from 54% (unmodified VMT catalyst) to 84% (modified catalyst). BET, XRD, XPS, NH3-TPD, H2-TPR, and in situ DRIFTs were employed to characterize the physicochemical properties and reaction mechanisms of the catalysts. The introduction of γ-Fe2O3 increased the V5+/V4+ ratio, surface chemisorbed oxygen content, redox ability, and a number of acid sites in the prepared catalysts. XPS confirmed the addition of γ-Fe2O3 introduced new charge transfer pathways (Fe3+/Fe2+ ↔ V5+/V4+). In situ DRIFTs suggested that the addition of γ-Fe2O3 to the catalyst significantly increased the adsorption capacity of catalyst for NH3 and NOx, while also exerting a strong activating effect on the adsorbed NH3. Furthermore, selective catalytic reduction over the VMT and 5PEG@1.25Fe-VMT catalysts followed the Eley-Rideal (E-R) mechanism. At temperatures above 200 °C, the 5PEG@1.25Fe-VMT catalyst also followed the Langmuir-Hinshelwood (L-H) mechanism.

FeCoNiMgB high-entropy boride powder with a fluffy cotton structure and enhanced activity in the oxygen evolution reaction

Exploring efficient, low-cost electrocatalysts is critical for improving the efficiency of water splitting reactions. Noble-metal-based oxides exhibit high activities in the oxygen evolution reaction (OER). However, their high cost and the lack of natural resources hinder their practical application. Therefore, in this study, we successfully synthesized an FeCoNiMgB high-entropy boride powder via a facile chemical reduction method for use as an OER catalyst in an alkaline medium. The FeCoNiMgB powder, with an ultrathin fluffy cotton structure, exhibited an excellent OER catalytic performance, affording an overpotential of 268 mV at a current density of 10 mA/cm2 and a low Tafel slope of 42.9 mV/dec; this performance was superior to those of FeCoNiB, FeNiMgB, CoNiMgB, FeCoMgB, and commercial RuO2. The FeCoNiMgB powder also displayed remarkably stable catalytic properties for >72 h with no clear evidence of degradation. Finally, using theoretical calculations, the excellent OER performance of FeCoNiMgB was verified in terms of its adsorption and charge transfer energies and covalence. The performance and stability of FeCoNiMgB were equivalent or superior to those of several nanostructured catalysts, and thus, this study provided valuable insight into the design of efficient high-entropy boride materials.

Zn-assisted low-temperature reconstruction of NiCo heterogeneous catalysts for lithium-oxygen batteries

Developing catalysts with high catalytic activity and durability is an effective strategy for improving the electrochemical performance of lithium-oxygen batteries (LOBs). Metal atom doping and heterostructure construction have shown great potential in catalysis and are expected to be widely used in energy storage. In this study, a Zn-doped NiCo2O4/NiO heterostructured complex catalyst is designed and prepared as a cathode catalyst for LOBs. This metal-doped heterostructured complex catalyst, prepared at a lower annealing temperature, retains the most active sites. Additionally, the three-dimensional hollow structure of the catalyst not only facilitates mass transfer but also provides active sites through doping and heterostructure formation. The Zn-doped NiCo2O4/NiO catalyst exhibits excellent catalytic performance, resulting the generation of a silky Li2O2 discharge product film, and the higher adsorption energy for the intermediate product LiO2 also allows the discharge product to be tightly bound to the catalyst. The improved contact between the discharge products and the catalyst's active sites, along with the increased surface area, enhances charge transport and decomposition properties, leading to good reversibility of the LOB. Consequently, the LOB based on Zn-doped NiCo2O4/NiO heterostructure complex catalyst features high discharge capacity (12160 mAh/g at 200 mA g−1) and excellent durability (353 cycles, ∼1765 h). Furthermore, theoretical calculations show that the Zn-doped complex heterostructures have enhanced reaction kinetics of OER and ORR. This straightforward method of producing metal-doped heterostructured complex catalysts that induce uniform Li2O2 deposition valuable insights for enhancing the performance of LOBs.

Highly efficient peroxymonosulfate activation by CoFe2O4@attapulgite–biochar composites: Degradation properties and mechanism insights

Sulfate radical-based advanced oxidation processes (SR-AOPs) have been considered as a promising approach for degrading organic pollutants. Herein, CoFe2O4 anchored on attapulgite-biochar composites (CoFe2O4@ATP–BC) were synthesized by a sol-gel co-pyrolysis method and showed excellent catalytic performance, reusability and stability in activating peroxymonosulfate (PMS) for the degradation of Rhodamine B (RhB). The effects of PMS concentration, catalyst dosage, temperature, initial pH, NOM and inorganic ions on the removal of RhB were investigated. The radical quenching experiments and electron paramagnetic resonance (EPR) measurement confirmed that 1O2, O2∙− and surface-bound ∙OH and SO4∙− were major reactive oxygen species (ROS) in the RhB degradation by CoFe2O4@ATP–BC/PMS system, indicating that radical and non-radical degradation pathways were both involved. The possible catalytic mechanism of PMS by CoFe2O4@ATP–BC was proposed including the interface reaction and bulk reaction. The main degradation intermediates were identified by liquid chromatograph-mass spectrometry (LC-MS), and three possible degradation pathways of RhB were deduced accordingly. In general, the CoFe2O4@ATP–BC/PMS system provided fundamentals of theoretical and applied research to further develop supported bimetallic oxides for advanced oxidation treatment of organic wastewater.