Enhancement Of Catalytic Activity Research Articles

The interplay between surface area and sulfur doping of carbon support on Pt NPs nucleation and growth: A synergistic enhancement of catalytic activity for oxygen reduction

Metal–carbon interaction plays a fundamental role in tuning the electrocatalytic behavior of metal nanoparticles (NP). The aim of this study is to emphasize the effective synergy between sulfur doping and the porous structure of the carbon support on the Pt NPs morphology and dimension. Thiophenic-like defects exert a metal-support interaction that affects Pt NPs nucleation and growth and their catalytic activity versus the oxygen reduction reaction (ORR), which makes them promising candidates for the cathode side of PEMFC. Pt NPs defectivity, size, and size dispersion were asserted by using synchrotron wide-angle X-ray total scattering and advanced data analysis. The analyses confirm a mutual correlation between the carbon surface area and the density of sulfur groups with the Pt-specific surface area and with their electrocatalytic properties. The catalytic activity for ORR reaches its peak when a balance is struck between the mesoporosity and the sulfur functionalization of the carbon support.

Enhancement of catalytic activity over Cu-supported montmorillonite catalyst for hydrogen production via steam reforming of dimethyl ether

Enhancement of catalytic activity over Cu-supported montmorillonite catalyst for hydrogen production via steam reforming of dimethyl ether

The role of oxide supports in constructing plasma-treated gold nanocatalysts for visible light photocatalytic oxidation of CO

Supported Au nanocatalysts are highly attractive plasmonic nanostructures for visible light (VL) photocatalysis due to their significant promise in direct conversion of solar to chemical energy. A promising strategy to prepare high-performance supported plasmonic Au nanocatalysts is treating the catalysts with plasma, where the support holds the key to constructing active Au-support interfaces by interacting with Au nanoparticles. Herein the role of oxide supports in constructing plasma-treated plasmonic Au nanocatalysts for VL photocatalytic oxidation of CO is studied by comparing effect of plasma treatment on typical oxides of TiO2, CeO2 and Al2O3 supported Au nanocatalysts. After O2 plasma treatment, CeO2 supported Au nanocatalyst obtains the highest intrinsic catalytic activity due to its high dispersion of Au nanoparticles induced by strong interaction between CeO2 and Au and strong oxygen activation ability. The O2 plasma treatment enables TiO2 supported Au nanocatalyst to exhibit the largest enhancement in catalytic activity under VL irradiation, which originates from the favorable hot-electron transfer process. This process is not only attributed to the strong surface plasmon resonance of Au nanoparticles and large numbers of Au-TiO2 interfacial sites that result from moderate interaction between TiO2 and Au, but also depends on the low Schottky barrier height at Au-TiO2 interface due to the small work function difference between TiO2 and metallic Au. This investigation deepens the understanding of the role of oxide supports in constructing plasma-treated supported Au nanocatalysts, and can be instructive for the design and optimization of plasmonic Au nanocatalysts for VL photocatalytic reactions.

The Origin of Strain Effects on Sulfur Redox Electrocatalyst for Lithium Sulfur Batteries

AbstractIntroducing strain is considered an effective strategy to enhance the catalytic activity of host material in lithium‐sulfur batteries (LSB). However, the introduction of strain through chemical methods often inevitably leads to changes in chemical composition and phase structure, making it difficult to truly reveal the essence and root cause of catalytic activity enhancement. In this paper, strain into MoS2 is introduced through a simple heat treatment and quenching. Experimental research and theoretical analysis show that the strain raises parts of antibonding orbitals in Mo─S bonds above the Fermi level and weakens Li─S and S─S bonds, resulting in tight anchoring and accelerating the conversion for lithium polysulfides (LiPSs). The cells based on the MoS2 with high strain delivers an initial discharge specific capacity as high as 1265 mAh g−1 under 0.2 C and a low average capacity fading of 0.041% per cycle during 1500 cycles under 1 C. This research work deeply reveals the origin of strain effects in the reaction process of LSB, providing important design principles and references for the rational design of high‐performance catalytic materials in the future.

Abstract C083: HDAC6 inhibition increases proteasome activity and modulates the myeloma immunopeptidome to promote cytotoxic T-cell activity

Abstract The proteasome functions as an essential component of immune surveillance by generating peptides from intracellular antigens that are then presented to cytotoxic T-cells. The vast majority of defined antitumor T-cell responses involves the proteasomal processing of intracellular proteins and their presentation in the context of major histocompatibility complex (MHC) class I molecules to antigenic peptide-specific CD8+ T-cells. Such antigenic peptides generated by the proteasome are generally 8-10 amino acids in length and mirror the linear sequence of the parental protein. However, immune evasion is a hallmark of cancer cells that disrupt the antigen processing and presentation machinery. Tumors develop strategies to evade host immunity and resist current immunotherapies, while others display a low tumor mutation burden limiting the presence of tumor antigenicity. Here, we postulated that pharmacologic enhancement of proteasome catalytic activity would increase MHC class I antigen presentation, modulate the myeloma immunopeptidome, and promote CD8+ T-cells anti-myeloma activity. A cell-based, high-throughput screen revealed that the histone deacetylase 6 (HDAC6) inhibitors tubastatin-A, ACY-738 and ACY-1215 increased proteasome activity in multiple myeloma (MM) cells. HDAC6 inhibitors increased pan-MHC class-I expression in MM cells as well as a panel of cancer cell lines. Treatment of MM patient tumor cells with HDAC6 inhibitors increased the cytotoxic effect of autologous patient-derived T-cells. Mechanism-based studies demonstrated that pharmacologic blockade or genetic ablation of the HDAC6 ubiquitin-binding (BUZ) domain disrupted HDAC6 association with HR23B, a substrate-shuttle factor that delivers ubiquitinylated cargo to proteasomes. HDAC6 inhibitors or HDAC6-BUZ domain deletion reduced the association of HR23B with HDAC6 and promoted binding of HR23B to proteasomes and a consequent increase in proteasome activity. The results validate the HDAC6-BUZ domain as an attractive drug discovery target and demonstrate that proteasome activators enhance antitumor immunity. Proteasome activators represent a paradigm-shifting approach to overcome mechanisms of immune escape in cancer cells. FDA-approved drugs that increase proteasome activity and boost antigen presentation and can be repositioned as cancer immunotherapeutics to overcome the existing bottlenecks in drug development. Taken together, our results highlight the breadth and magnitude of the proteasome in governing fundamental cellular processes and the immense potential of therapeutics that exploit proteasomes to treat human disease. Citation Format: Priyanka S. Rana, James J. Ignatz-Hoover, James J. Driscoll. HDAC6 inhibition increases proteasome activity and modulates the myeloma immunopeptidome to promote cytotoxic T-cell activity [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C083.

Instructive Synergistic Effect of Coordinating Phosphorus in Transition-Metal-Doped β-Phosphorus Carbide Guiding the Design of High-Performance CO2RR Electrocatalysts.

Developing efficient electrocatalysts for the CO2 reduction reaction (CO2RR) is the key and difficult point to alleviate energy and climate issues. The synergistic catalytic effects between metal and nonmetal elements have gained attention for the design of the CO2RR electrocatalysts. The realization of this effect requires a suitable combination of metal and nonmetal elements, as well as the support of suitable substrates. Based on this, the transition-metal-doped β-phosphorus carbide (TM-PC) (TM = 4d and 5d transition metals except Tc) catalysts are designed, and their structures, electronic properties, and CO2RR catalytic performances are studied in depth via first-principle calculations. The strong bonding ability and high reactivity brought by the moderate electronegativity and abundant electrons and orbitals of phosphorus are the key to the excellent catalytic performance of TM-PCs. Coordinating phosphorus atoms improve the catalyst activity in two ways: (1) regulating the electron transfer of the TM active site, and (2) acting as the active site and changing the reaction mechanism. With the participation of coordinating P atoms, the "relay" of active sites reduces the limiting potential values for the reduction from CO2 to CH4 catalyzed by Cr-PC and Mo-PC by 0.27 and 0.23 V, respectively, compared with pathways where only the TM atom is the active site, reaching -0.55 and -0.63 V, respectively. Regarding the coordinating P atom as the second active site, Cr-PC and Mo-PC can catalyze the production of CH3CH2OH at limiting potential values of -0.54 and -0.67 V, respectively. This study demonstrates the dramatic enhancement of catalytic activity caused by suitable nonmetal coordinating atoms such as P and provides a reference for the design of high-performance CO2RR electrocatalysts based on metal-nonmetal coordinating active centers.

Glycerol-assisted dynamic hydrothermal synthesis of nickel phyllosilicate for enhanced CO2 methanation: Synergistic effect of stirring and viscous solvent

To address the shortcomings of poor convection and product agglomeration of the static hydrothermal method, the dynamic hydrothermal method together with the viscous solvent-assisted dynamic hydrothermal method were proposed to synthesize Ni-phyllosilicate in this work. Stirring seemed to be powerful to accelerate the synthesis with significant increase of Ni content from 11.80 wt% (static synthesis) to 23.13 wt% (dynamic synthesis). The further modification of glycerol increased the shearing force to exfoliate the Ni-phyllosilicate nanosheets during dynamic synthesis, whose thickness could reach 1.17 nm with improved metal utilization ratio after reduction. As a result, the activity of CO2 methanation was enhanced with large TOFCO2 of 3.5 × 10−2 s−1 and small Ea of 65.13 kJ·mol−1. In situ DRIFTS analysis confirmed the existence of high actively intermediate of m-HCOO− and *CO, which could be further hydrogenated into CHx species. In short, the synergistic effect of dynamic stirring and glycerol modification drove the enhancement of catalytic activity, and also provided the possibility of large-scale production of Ni-phyllosilicate using hydrothermal method.

Kinetic modeling on oxidation of arabinose to arabinonic acid in base-free medium over synergistic PtCu/TiO2 catalyst

Arabinonic acid (AA) is an essential building block for the food and pharmaceutical industries. However, green and atomically efficient synthesis of AA remains a grand challenge, as most previous reports have been focused on the alkaline-promoted oxidation of arabinose. In this work, we firstly reported lumped kinetic modeling of the oxidation of arabinose to AA in base-free medium, with detailed reaction networks involved in the C-H and C-C cleavage reactions. It is found that the bimetallic PtCu/TiO2 catalyst displays strong synergism due to electronic coupling at metal-support interface, leading to an almost two-fold enhancement in catalytic activity in comparison with monometallic Pt/TiO2 catalyst. According to detailed analysis on reaction network and kinetic modeling, the presence of Cu mainly contributes to formulating additional active sites for the oxidation and C-C cleavage reactions. The quantitative assessment for conversion of arabinose could provide useful information for modeling and process development for various other important sugars.

Substrate-Driven Electrocatalysis of Natural and Earth-Abundant Pyrite Towards Oxygen Evolution Reaction

The fabrication of an economical, earth-abundant, environment-friendly, and highly efficient electrocatalyst for anodic oxygen evolution reaction (OER) in the electrolysis of water is essential for sustainable energy conversion and storage technology. Among the various transition metal-based electrocatalysts, iron-based electrocatalysts are well-known for their catalytic behavior due to their effective redox activity, abundance, and low toxicity. Pyrites are the most prevalent Fe-containing minerals in the earth's crust, but their use as an electrocatalyst for oxygen evolution reaction (OER) has received little attention though their synthetic counterparts have shown better activity. Herein, the naturally occurring pyrite (FeS2) on Ni foam is evaluated as a dynamic electrocatalyst towards OER in alkaline media. Various spectro-analytical techniques have been used to confirm the chemical and physical characteristics of earth abundant pyrite. The pyrite-coated nickel foam exhibited an extraordinarily superior catalytic activity for OER with overpotential of 203 and 315 mV at current densities of 10 mA∙cm−2 and 50 mA∙cm−2, respectively in 1.0 M potassium hydroxide (KOH) electrolyte at a scan rate of 5 mV∙s−1. Meanwhile, the benchmark precious iridium oxide (IrO2) on nickel foam demonstrated an overpotential of 322 and 430 mV for OER at 10 and 50 mA∙cm−2, respectively. It's important to note that the catalyst used is a natural pyrite with some additional constituents in small quantities. Therefore, the analysis revealed the presence of carbon (C), silicon (Si) and oxygen (O) in addition to FeS2. This composition, along with the synergistic behavior of nickel ions from the nickel foam, likely contributes to the enhancement in catalytic activity observed. The pyrite on carbon substrate, did not exhibit the same impressive OER activity as like on Ni foam, emphasizing the significance of the substrate-dependent performance. Nevertheless, on the nickel foam, natural pyrite displayed the lowest overpotential, Tafel slope, and better stability for OER. Hence, on Ni foam substrate, earth-abundant, low-cost, stable, and efficient pyrite-based catalyst augmented by synergistic interactions with nickel ions, may hold great promise for advancing the field of water electrolysis and facilitating cleaner energy production and conversion.

Enhancing effect of cobalt phthalocyanine dispersion on electrocatalytic reduction of CO2 towards methanol.

This paper focuses on enhancing the performance of electrocatalytic CO2 reduction reaction (CO2RR) by improving the dispersion of cobalt phthalocyanine (CoPc), especially for the methanol formation with multi-walled carbon nanotubes (CNTs) as a support. The promising CNTs-supported CoPc hybrid was prepared based on ball milling technique, and the surface morphology was characterized by means of those methods such as scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FT-IR) and X-ray photoelectron spectra (XPS). Then, the synergistic effect of CNTs and ball milling on CO2RR performance was analyzed by those methods of cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), gas chromatography (GC), and proton nuclear magnetic resonance spectroscopy (1HNMR). Subsequently, the reduction mechanism of CO2 on ball-milled CoPc/CNTs was revealed based on the DFT calculations. The results showed that the electrocatalyst CoPc/CNTs hybrid prepared with sonication exhibited a conversion efficiency of CO2 above 60% at -1.0V vs. RHE, accompanied by the Faradaic efficiencies of nearly 50% for CO and 10% for methanol, respectively. The addition of CNTs as the support improved the utilization efficiency of CoPc and reduced the transfer resistance of species and electrons. Then the ball-milling method further improved the dispersion of CoPc on CNTs, which resulted in the fact that the methanol efficiency was raised by 6% and partial current density was increased by nearly 433%. The better dispersion of CoPc on CNTs adjusted the reduction pathway of CO2 and resulted in the enhancement of methanol selectivity and catalytic activity of CO2. The probable pathway for methanol production was proposed as CO2 → *CO2- → *COOH → *CO → *CHO → *CH2O → *OCH3 → CH3OH. This suggests the significance of the ball-milling method during the preparation of better supported catalysts for CO2RR towards those high-valued products.

Enhancing catalytic activity of zeolitic octahedral metal oxides through zinc incorporation for ethane oxidative dehydrogenation

Zeolitic octahedral metal oxides possess both redox properties and microporosity, making them highly active for catalysis. Tuning the property of micropore by incorporating transition metal ion in the pore improves the catalytic activity greatly. In this study, single Zn species was incorporated into a micropore of a zeolitic octahedral metal oxide based on vanadomolybdate. Structural characterization demonstrated that the crystalline structure remained unchanged, and the micropores remained unblocked in the presence of Zn. Furthermore, this incorporation of Zn improved the catalytic activity of ethane oxidative dehydrogenation, achieving a 50 % of ethane conversion and 90% of selectivity. The yield of ethylene remained consistently at 45 % over 35 h, demonstrating the high stability of the catalyst. Mechanism study revealed that the isolated Zn site not only activated both O2 and ethane, but also stabilized intermediates and transition states, leading to an increase in catalyst activity.

Co,N-codoped MoOx nanoclusters on graphene derived from polyoxometalate for highly efficient aerobic oxidation desulfurization of diesel

Aerobic oxidative desulfurization (AODS) offers a sustainable and cost-effective alternative to conventional diesel desulfurization techniques. However, despite its potential, the development of catalysts with both high activity and stability remains a critical challenge in this field. Here we present the synthesis of polyoxometalate (POM) derived Co,N-codoped MoOx nanoclusters on graphene sheets for boosting the AODS reactions, which combines the characteristics of sub-nanometer size of POMs and excellent stability of metal oxides. Through experimental characterizations and density functional theory (DFT) calculations, we demonstrate that the MoOx nanoclusters can effectively activate O2 by electron transfer, while the doped Co and N elements further optimize the electronic structure of Mo sites, resulting in a significant enhancement in catalytic activity. The optimized catalyst exhibits an impressive turnover frequency of 67.88 h−1 in the oxidation of dibenzothiophene (DBT), facilitating the rapid conversion of various thiophenes under mild conditions. The catalyst also demonstrates prominent durability in seven cycles of reuse with consistent catalytic performance and unchanged chemical structure. More importantly, the catalyst achieves deep AODS of real diesel, showcasing its potential for practical applications.

Curvature effects regulate the catalytic activity of Co@N4-doped carbon nanotubes as bifunctional ORR/OER catalysts

The advancement of metal-air batteries relies significantly on the development of highly efficient bifunctional catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, we investigate the potential application of Co@N4-doped carbon nanotubes (Co@N4CNTs) as bifunctional catalysts using density functional theory calculations. We explore the stability and electronic properties of Co@N4CNTs by analyzing energies, bond lengths, conducting ab initio molecular dynamics simulations, and examining the density of states. Notably, the diameter of the nanotubes has a notable impact on the catalytic performance of Co@N4CNTs. A remarkable 54% improvement in catalytic activity when transitioning from (4, 4) to (24, 4) Co@N4CNTs, with ηBi from changing from 1.40 to 0.64 V. We have several exceptional catalysts with low overpotentials, including (18, 4), (22, 4), and (24, 4) Co@N4CNTs, which exhibit ηBi values of 0.68, 0.67, and 0.64 V, respectively. Moreover, we link the increased activity of Co@N4CNTs to the change of Co atom’s partial d orbital energy, facilitated by adjustments in the diameter of Co@N4CNTs. This revelation offers valuable insights into the underlying factors driving the enhancement of catalytic activity through alterations in orbital energy levels. Our research uncovers several excellent catalysts and provides valuable insights for the design and development of efficient catalysts for metal-air batteries.

Rational construction of hollow ZnO@SnS2 core-shell nanorods: A way to boost catalytic removal of Cr (VI) ions, antibiotic and industrial dyes

Herein, the novel hollow ZnO@SnS2 core-shell nanorods with variable shell thickness have been synthesized by a chemical synthesis approach. The transmission electron microscopy (TEM) images signified the creation of a hollow core-shell nanostructure. The SnS2 layer coating on ZnO nanorods broadens visible light absorption and suppresses near-band edge emission of ZnO nanorods. Interestingly, the band gap (optical) of the developed ZnO nanorods decreased from 3.3 eV to 2.1 eV after the coating of SnS2 shell. Consequently, the coated hollow ZnO@SnS2 core-shell nanorods displayed a significant enhancement in catalytic activity for the decomposition of toxic industrial dyes, pharmaceutical pollutant tetracycline, and Cr(VI) ion in comparison to hollow ZnO NRs. The photon-induced charge carrier generation and separation were confirmed by the three-electrode electrochemical amperometric analysis and impedance analysis under illumination of simulated solar light (AM 1.5, One Sun). Moreover, an exceptionally higher photocurrent generation (∼10 times higher than ZnO nanorod). The improved ZnO@SnS2 core shell NRs catalytic activity was attributed to its core-shell structure, proper band structure, and effective charge carrier transfer across the core shell interface. This work offers new insights for the design and growth of visible light-active core shell nanorods for resolving environmental pollution and photocurrent generation.

Enhancement of Bifunctional Catalytic Performance of G‐C3N4@ Ag Composite by NaBH4 Etching

AbstractHerein, a novel composite of g‐C3N4 and silver nanoparticles(g‐C3N4@Ag) with enhanced bifunctional catalytic activity through chemical etching is reported. A kind of g‐C3N4@Ag composite by one‐pot route, then treated the product with sodium borohydride (NaBH4) solution for a certain time is first synthesized. The property and morphology of the g‐C3N4@Ag composite changed greatly after the treatment. Compared with the pristine g‐C3N4@Ag composite, the NaBH4‐etching endowed g‐C3N4@Ag composite (RACN) with smoother two‐dimensional plane structure, as well as an extension of the conjugate system which originating from the stronger chemical connection between the Ag nanoparticles and g‐C3N4. Furthermore, research results indicated that the RACN showed superior broad‐spectrum catalytic performance for the reduction of aromatic nitro compounds, and the catalytic efficiency of the RACN is enhanced dozens of times by the treatment. Moreover, the photocatalytic activity of the RACN is also greatly improved. This discovery provides an efficient and facile method toward the enhancement of catalytic activity of semiconductor and metal nanoparticle composites by chemical etching.

S2O82−/CeO2 Solid Superacid Catalyst Prepared by Radio-Frequency Plasma-Assisted Hydrothermal Method

CeO2 was prepared using a hydrothermal method, modified by radio-frequency plasma in the form of glow discharge, and then the solid superacid S2O82−/CeO2 was prepared by the impregnation method. A series of properties such as pore structure was characterized by N2 adsorption–desorption experiments, surface morphology was characterized by TEM, crystal phase was characterized by XRD, and surface acidity of the catalyst was characterized by Py-IR and Hammett titration. The methyl esterification reaction of tryptophan was used to evaluate the activity of the solid superacid. The results showed that the catalyst modified by radio-frequency plasma had a larger specific surface area, more surface oxygen vacancies, smaller particle size, and higher total acid content. The yield of tryptophan methyl ester reached a higher level of 94.5% (150 °C, 1 MPa, 2 h), catalyzed by the modified S2O82−/CeO2. This work verified the feasibility of plasma technology in the field of catalytic activity enhancement of solid superacid.

MoO2/Ni heterojunction with strong electronic coupling prepared by in-situ phase separation for High-Efficiency nitrate electroreduction to ammonia

Further improvements in ammonia selectivity and Faraday efficiency are severely hampered by the complexity of the nitrate reduction process and the intense competitive reaction. Therefore, it is awfully imperative to develop highly active NITRR electrocatalysts and further investigate their catalytic mechanism. In this work, MoO2/Ni cuboids with intimate interfaces were constructed by in-situ phase separation induced strategy for electrocatalytic reduction of nitrate and selective synthesis of ammonia, further expanding the application field of this metallic oxide-metal heterostructure catalyst. The experimental results indicate that the strong interaction between MoO2 and Ni causes the redistribution of interfacial charges, which reasonably explains the extraordinary NITRR activity of MoO2/Ni. In addition, the exposure of numerous active sites at the interface and the amelioration of inherent conductivity are also advantageous for the enhancement of catalytic activity. The theoretical results elucidate the detailed catalytic mechanism. MoO2/Ni showcases lower·NH3 desorption energy and higher hydrogen adsorption energy than pure MoO2 and Ni, which promotes the production of ammonia. In short, the strong electronic interaction between MoO2 and Ni tailors the electronic structure of MoO2/Ni, thus regulating the adsorption energy of the intermediates, and observably improving the FE (95.9%) and ammonia selectivity (96.9%) of MoO2/Ni.

Photothermally Triggered Nanoreactors with a Tunable Catalyst Location and Catalytic Activity.

Thermosensitive microgels based on poly(N-isopropylacrylamide) (PNIPAm) have been widely used to create nanoreactors with controlled catalytic activity through the immobilization of metal nanoparticles (NPs). However, traditional approaches with metal NPs located only in the polymer network rely on electric heating to initiate the reaction. In this study, we developed a photothermal-responsive yolk-shell nanoreactor with a tunable location of metal NPs. The catalytic performance of these nanoreactors can be controlled by both light irradiation and conventional heating, that is, electric heating. Interestingly, the location of the catalysts had a significant impact on the reduction kinetics of the nanoreactors; catalysts in the shell exhibited higher catalytic activity compared with those in the core, under conventional heating. When subjected to light irradiation, nanoreactors with catalysts loaded in the core demonstrated improved catalytic performance compared to direct heating, while nanoreactors with catalysts in the shell exhibited relatively similar activity. We attribute this enhancement in catalytic activity to the spatial distribution of the catalysts and the localized heating within the polydopamine cores of the nanoreactors. This research presents exciting prospects for the design of innovative smart nanoreactors and efficient photothermal-assisted catalysis.

Robust cobalt-free perovskite type electrospun nanofiber cathode for efficient electrochemical carbon dioxide reduction reaction

Solid oxide electrolysis cell (SOEC) is a very competent device for cleanly and efficiently electrochemical carbon dioxide reduction reaction (CO2RR) to high-value added carbon monoxide (CO). However, the low specific surface area and the three-phase boundary (TPB) as the disadvantages of traditional powdery cathode hinder the development of SOEC. Herein, a cobalt-free perovskite oxide Sr2Fe1.5Mo0.5O6-δ nanofiber (SFM-NF), synthesized by the electrospinning technique, is explored as the cathode for CO2RR. The cathode polarization resistance measured by the symmetric cell is reduced from 2.01 Ω cm2 for nanoparticle (SFM-NP) cathode to 1.61 Ω cm2 for SFM-NF cathode at 800 °C in CO:CO2 (2:1) atmosphere. In addition, the corresponding current density of the single cell is greatly increased from 0.732 to 1.173 A cm−2 under 2.0 V and 800 °C. These results all indicate the enhancement of CO2RR catalytic activity. The distribution relaxation of times analysis results for the electrochemical impedance spectra reveal that the increase of surface oxygen species at the interface for SFM-NF cathode allows for a more rapid oxygen ion transport path, and accelerates the CO2RR in a SOEC. This work provids an insightful way for the optimization mechanism of electrode, guiding the development of robust and efficient CO2RR device.

Catalytic removal of harmful volatile organic compounds by reutilizing zinc rods waste from spent batteries as a palladium catalyst support

The emission of volatile organic compounds (VOCs) has led to significant deterioration in air quality, making it imperative to ensure that these compounds are removed from emission sources before they are released into the atmosphere. In this context, the present study recycled spent primary batteries to use their zinc rods waste (ZRW) as a palladium catalyst support for the removal of harmful VOCs. To this end, palladium supported on ZRW (Pd/ZRW) catalysts were prepared and tested for the catalytic oxidation of benzene, methylbenzene and 1,2-dimethylbenzene. The physicochemical properties of the Pd/ZRW catalysts were carefully characterized by ICP-OES, BET, SEM, XRD, FE-TEM, XPS, and H2-TPR analyses. The main component of ZRW was identified as ZnO. Consistent with expectations, increases in the loading of Pd from 0.1 to 1.0 wt% in the Pd/ZRW catalysts resulted in enhanced VOCs removal efficiency. The reaction temperature required for the complete oxidation (100% removal efficiency) of methylbenzene and 1,2-dimethylbenzene on the 1.0 wt% Pd/ZRW catalyst was below 340 °C at a gas hourly space velocity of 50,000 h−1. TEM, XPS, and H2-TPR results implied that the enhancement of catalytic activity with the addition of Pd could be attributed to the readily movable surface lattice oxygen as well as the active component (Pd species). Ultimately, ZRW of spent primary batteries appear to show promise as a catalyst support for VOCs removal. This study has introduced a novel strategy for reducing air pollutants by utilizing waste, which promotes the disposal of hazardous solid waste and ensures clean air quality.