Oxidation Route Research Articles

Solar Selectivity of Silver Nanoparticles Modified Copper Oxide Nanocomposite Thin Films Prepared by Facile Chemical Oxidation Method

AbstractSilver nanoparticles modified copper oxide nanocomposite thin films (Ag‐CuO NC TFs) and pristine CuO TF were successfully synthesized on copper substrates using a chemical oxidation route. X‐ray diffractometry (XRD) characterization of Ag‐CuO NC TFs revealed the formation of monoclinic crystal structured CuO. Scanning electron microscopy (SEM) images showed a star‐like grain morphology of the Ag‐CuO NC TFs. Energy dispersive X‐ray spectroscopy (EDX) analysis ascertained the presence of anticipated elements without impurities. Fourier transform infrared spectroscopy (FTIR) investigation confirmed the presence of Ag NPs on CuO in the Ag‐CuO NC TFs. Raman spectroscopy examination indicated the presence of a spinel structure with vibrational and tetrahedral sites. UV‐Vis‐NIR reflectance analysis demonstrated that Ag‐CuO NC TFs with 2.0 wt.% Ag NPs exhibited solar absorptance of 72.39 %, thermal emittance of 4.3 %, and a highest solar selectivity of 16.83 among the prepared thin films. These results suggest that the Ag‐CuO NC TFs could be promising candidates for use as solar selective absorbers in solar thermal energy conversion devices.

Earth-Abundant CuWO4 as a Versatile Platform for Photoelectrochemical Valorization of Soluble Biomass Under Benign Conditions.

Here, a nanosheet-structured CuWO4 (nanoCuWO4) is demonstrated as a selective and stable photoanode for biomass valorization in neutral and near-neutral solutions. nanoCuWO4 can be readily prepared by a solid phase reaction using nanosheet-structured WO3 as the template. Several substrates, including glucose, fructose and glycerol, are investigated to reveal the wide applicability of nanoCuWO4. The activity and product distribution trends in biomass valorization are investigated at different pH by taking advantage of the promising stability of nanoCuWO4 in a wide pH range. Product analyses confirm that formate production with a Faradaic efficiency (FE) of 76 ± 5% and glycolate production with an FE of 61 ± 8% can be achieved by glucose and fructose valorization at pH 10.2, respectively. On the other hand, glyceraldehyde and dihydroxyacetone (DHA)are the main products in the glycerol valorization, accounting for an FE of over 85% at pH 7. Notably, nanoCuWO4 has the highest FE of DHA in photoelectrochemical (PEC)glycerol valorization compared to WO3 and BiVO4 at neutral pH. The oxidation routes and mechanism of glycerol valorization on nanoCuWO4 are also under investigation. The co-production of H2 and value-added chemicals is finally demonstrated using a photovoltaic cell connected to a nanoCuWO4-based PEC glycerol valorization system.

Revealing OH species in situ generated on low-valence Cu sites for selective carbonyl oxidation

Catalytic oxidation through the transfer of lattice oxygen from metal oxides to reactants, namely the Mars-van Krevelen mechanism, has been widely reported. In this study, we evidence the overlooked oxidation route that features the in situ formation of surface OH species on Cu catalysts and its selective addition to the reactant carbonyl group. We observed that glucose oxidation to gluconic acid in air (21% O2) was favored on low-valence Cu sites according to X-ray spectroscopic analyses. Molecular O2 was activated in situ on Cu0/Cu+ forming localized, adsorbed hydroxyl radicals (*OH) which played the primary reactive oxygen species as confirmed by the kinetic isotope effect (KIE) study in D2O and in situ Raman experiments. Combined with DFT calculations, we proposed a mechanism of O2-to-*OH activation through the *OOH intermediate. The localized *OH exhibited higher selectivity toward glucose oxidation at C1HO to form gluconic acid (up to 91% selectivity), in comparison with free radicals in bulk environment that emerged from thermal, noncatalytic hydrogen peroxide decomposition (40% selectivity). The KIE measurements revealed a lower glucose oxidation rate in D2O than in H2O, highlighting the role of water (H2O/D2O) or its derivatives (e.g., *OH/*OD) in the rate-determining step. After proving the C1-H activation step kinetically irrelevant, we proposed the oxidation mechanism that was characterized by the rate-limiting addition of *OH to C1=O in glucose. Our findings advocate that by maneuvering the coverage and activity of surface *OH, high-performance oxidation of carbonyl compounds beyond biomass molecules can be achieved in water and air using nonprecious metal catalysts.

Hydrogen Peroxide Heterolytic Cleavage Induced Gas Phase Photo-Fenton Oxidation of Nitric Oxide.

Nitric oxide (NO) is one of the major air pollutants that may cause ecological imbalance and severe human disease. However, the removal of NO faces challenges of low efficiency, high energy consumption, and production of toxic NO2 byproducts. Herein, we report an efficient *OOH intermediate-involved NO oxidation route with high NO3- selectivity via a gas phase photo-Fenton system. Fe single atoms (Fe SAs)-anchored NH2-UiO-66(Zr) (Fe SAs@NU) was synthesized. The five-coordinated Fe SAs undergo a transient structure reconstitution during the photo-Fenton process, which enables a novel heterolytic cleavage pathway of H2O2 to derive specific ·OOH/·O2- radicals as reactive oxygen species. Therefore, a high NO (550 parts per billion) removal rate of 81% (NO3- selectivity up to 99%) is achieved under visible-light irradiation (>420 nm). This study provides new insight for the high-performance photo-Fenton process via a transient structure reconstitution pathway for the removal of gas phase NOx pollutants.

Insight into the nonradical selective oxidation mechanism for versatile organic pollutants removal by perovskite activated peroxymonosulfate system

The heterogeneous catalysis of peroxymonosulfate (PMS) through nonradical pathway has shown many advantages in environmental remediation. It is necessary to unveil the factors affecting oxidation routes and selectivity toward different organic pollutants. Herein, a series of ABO3-type BiFexCo1-xO3 perovskite catalysts were fabricated via simple hydrothermal process to realize the changeover of catalytic activity and mechanism in PMS activation and pollutants oxidation. The as-prepared BiFe0.5Co0.5O3 (BFCO-3) achieved a 98 % removal efficiency of SMZ with a high kinetic constant (kobs = 0.334 min−1) in 10 min. The superior catalytic performance was ascribed to the introduction of bimetals at B-site, which enhanced electron donating capacity to PMS, confirming by d-band center calculations. Several parameters such as inorganic anions and humic acids affected the SMZ degradation slightly, owing that singlet oxygen was verified to be the primary reactive species in the BFCO-3/PMS system. Moreover, twelve organic pollutants including amoxicillin crystalline (AMX), cephalexin hydrate (CFX), ciprofloxacin (CIP), levofloxacin (LFX), Sulfadiazine (SDZ), sulfamethoxazole (SMZ), 4-acetamidophenol (ACP), benzoic acid (BA), bisphenol A (BPA), carbamazepine (CBZ), metronidazole (MNZ) and naproxen (NPX) were utilized to investigate the selective oxidation mechanism. A linear correlation between lnkobs and their half-wave potential (φ1/2) values (except for BA and MNZ) suggesting the dominant role of nonradical catalysis where phenolic compounds with lower anodic potential tend to lose electrons are more easily degraded. Furthermore, the reactive sites of representative SMZ for electrophilic species attack were precisely identified based on the Fukui index. And the degradation intermediates of SMZ were further determined by LC-MS/MS technology for proposing their degradation pathway and predicting ecotoxicity. This study not only provides an efficient advanced oxidation system for organic pollutants removal but also advances our understanding of the selective oxidation mechanism in nonradical-dominated catalytic process.

A Green and Efficient Electrocatalytic Route for the Highly-Selective Oxidation of C-H Bonds in Aromatics over 1D Co3O4-Based Nanoarrays.

Electrocatalytic oxidation of C-H bonds in hydrocarbons represents an efficient and sustainable strategy for the synthesis of value-added chemicals. Herein, a highly selective and continuous-flow electrochemical oxidation process of toluene to various oxygenated products (benzyl alcohol, benzaldehyde, and benzyl acetate) is developed with the electrocatalytic membrane electrodes (ECMEs). The selectivity of target products can be manipulated via surface and interface engineering of Co3O4-based electrocatalysts. We achieved a high benzaldehyde selectivity of 90% at a toluene conversion of 47.6% using 1D-Co3O4 nanoneedles (NNs) loaded on a microfiltration (MF) titanium (Ti) membrane, i.e, Co3O4 NNs/Ti. In contrast, the main product shifted to benzyl alcohol with a selectivity of 90.1% at conversion of 32.1% after modifying MnO2 nanosheets (NSs) on Co3O4 NNs/Ti (Co3O4@MnO2/Ti) catalyst. Moreover, benzyl acetate product can be obtained withselectivity of 92% at a conversion of 58.5% at high current density (> 1.5mA cm-2), demonstrating that the pathway of toluene oxidation is readily maneuvered. DFT results reveal that modifying MnO2 on Co3O4 optimizes the electron structure of Co3O4@MnO2/Ti and modulates the adsorption behavior of intermediate species. This work demonstrates a sustainable,and continuous-flow process for precise control over production selectivity of value-added oxygenated derivatives in electrochemical oxidation of aromatic hydrocarbons.

Kinetic analysis on the hydrogen cyanide formation in the premixed methane/ammonia flame

Hydrogen cyanide (HCN) is a highly toxic trace emission that may be generated during ammonia (NH3) blended hydrocarbon combustion. In this study, a new kinetic model was developed and validated to predict HCN formation in NH3-blended combustion. Key rate coefficients for nitrogen-substituted hydrocarbon species were critically reevaluated. Using a one-dimensional freely propagating flame model, the formation of HCN in laminar premixed CH4/NH3/air flames was systematically analyzed under various conditions. Results indicate that HCN emission increases with increasing equivalence ratio (ϕ) and non-monotonically changes with NH3 blending ratio (α). Under lean conditions, HCN is primarily formed from the decomposition of imine radicals and oxidized by O/OH inside the flame front. While under rich conditions, the HCN oxidation takes place in the post-flame region, making the emissions at the outlet highly dependent on the reaction residential time. Consequently, attention should be paid to HCN emissions under high NH3 blending fraction (α > 50 %), and ultra-rich conditions (ϕ > 1.2) at normal temperature and pressure. The peak emission of HCN occurred at α = 0.7 and ϕ = 1.45, reaching a lethal concentration (310 ppm) in 1D premixed flame. Complex CHi and NHi interaction reactions are exhibited in the formation of HCN. The overall formation route can be divided into methylamine oxidation routes and radical combinations routes, and the former is dominant under all conditions. Independently increasing temperature or pressure will reduce the HCN emission due to the increased post-oxidation of HCN and diminished reaction characteristic time, respectively. More complicated changes in HCN were shown when temperature and pressure were increased at the same time. However, emissions will fall to a negligible level when temperature and pressure exceed 600 K and 2 atm, suggesting minimal concern for HCN emissions in CH4/NH3 combustion under elevated pressure and temperature conditions.

Selectively photocatalytic oxidation of methane to methanol promoted by Charge-Polarized Zn-Ti pairs

Photocatalysis offers an intriguing route for selective oxidation of CH4 to CH3OH under mild conditions. However, owing to the ultra-high stability of CH4 and the diversity of oxidative products, the activity of CH4 oxidation and the selectivity of CH3OH are still far from satisfactory. Herein, we report a dual-cocatalyst of Au and bimetallic oxide (Zn2Ti3O8) nanoparticles (NPs) modified TiO2 nanotube (Au/Zn2Ti3O8/TiO2) for highly active and selective photocatalytic oxidation of CH4 to CH3OH with O2 at room temperature. The introduction of Zn2Ti3O8 NPs is skillfully exploited the epitaxies of ZIF-8 on the surface of protonated titanate nanotubes (H-TNTs) and the followed thermal treatment with air. During photocatalytic CH4 oxidation, 1.7 %Au/Zn2Ti3O8/TiO2-4 achieved a formation rate of liquid oxygenates of 1200 μmol·gcat.–1·h−1 with a CH3OH selectivity of 91.5 %, which were much higher than those over 1.7 %Au/TiO2 and 1.7 %Au/ZnO. Mechanism investigation confirmed the presence of the strong electron interaction between Au NPs, Zn2Ti3O8 NPs and TiO2 nanotubes in 1.7 %Au/Zn2Ti3O8/TiO2-4, which intensified the charge polarization between Zn sites and Ti sites. These charge-polarized Zn-Ti sites were not only beneficial to the adsorption and activation of CH4, but also accelerated the further transformation of CH3OOH to CH3OH, as well as inhibited the excessive oxidation of CH3OH.

Green Molecular Reactor Boosting the Photocatalytic Aerobic Oxidation of Sulfides in Clean Solvent

AbstractThe synthesis of sulfoxides has long attracted considerable interest due to their pivotal role in organic synthesis, pharmaceutics and environmental protection. Oxidation of the corresponding sulfides is recognized as the most effective strategy. Traditional oxidation methods, however, fall short of the growing demands of green chemistry. Photocatalytic aerobic oxidation has thus garnered attention, employing the greenest and most sustainable oxidants—oxygen or air—and sunlight as the energy source. Nevertheless, these reactions are typically conducted in potentially pollutive organic solvents rather than in the greenest solvent, water. To facilitate this organic transformation in aqueous phase, molecular reactors that can encapsulate reactants within their confined pores and facilitate photocatalytic reactions have been developed recently. This Concept article summarizes the development of molecular reactors for the photocatalytic oxidation of sulfides and provides perspectives for the design and construction of effective photocatalytic molecular reactors.

Effective magnetic moment modulated perovskite-type oxides towards peroxymonosulfate activation: A high-valent metal species and superoxide radical step-by-step oxidation route

Perovskite oxides are considered as promising catalysts in activating peroxymonosulfate (PMS) for environmental remediation, but the intrinsic properties that govern the activity of perovskites are ambiguous. Herein, a series of perovskite-type oxides La2MeO4 (LMe, where Me = Co, Mn, Cu, and Fe) were reported to activate PMS for improving organic pollutant degradation, while the LCo/PMS system showed impressive performance, achieving over 90 % removal of organic contaminants (dyes and antibiotics) under the optimized conditions of 0.05 g/L catalyst and 0.50 mM PMS. Experiments and characterizations verified a good linear correlation between the catalytic activity and effective magnetic moment (μeff) of catalysts, underlining the key role of the spin state of the metal center in governing the intrinsic activity. Additionally, two stages of oxidation pathways were evidenced to be involved in the reaction: i) high-valent cobalt-oxo species (i.e., Co(IV)) were produced from the surface reactive complexes catalyst-PMS*, afterwards ii) a portion of superoxide radicals (O2•−) were formed via the PMS reaction with Co(IV). Overall, these findings provide new insights into the mechanism of the perovskite-activated PMS system for efficient water remediation.

Photothermal Assisted Biomass Oxidation for Pairing Carbon Dioxide Electroreduction with Low Cell Potential.

Integrating anodic biomass valorization with carbon dioxide electroreduction (CO2RR) can produce value-added chemicals on both the cathode and anode; however, anodic oxidation still suffers from high overpotential. Herein, a photothermal-assisted method was developed to reduce the potential of 5-hydroxymethyl furfural (HMF) electrooxidation. Capitalizing on the copious oxygen vacancies, defective Co3O4 (D-Co3O4) exhibited a stronger photothermal effect, delivering a local temperature of 175.47 °C under near infrared light illumination. The photothermal assistance decreased the oxidation potential of HMF from 1.7 V over pristine Co3O4 to 1.37 V over D-Co3O4 to achieve a target current density of 30 mA cm-2, with 2,5-furandicarboxylic acid as the primary product. Mechanistic analysis disclosed that the photothermal effect did not change the HMF oxidation route but greatly enhanced the adsorption capacity of HMF. Meanwhile, faster electron transfer for direct HMF oxidation and the surface conversion to cobalt (oxy)hydroxide, which contributed to indirect HMF oxidation, was observed. Thus, rapid HMF conversion was realized, as evidenced by in situ surface-enhanced infrared spectroscopy. Upon coupling cathodic CO2RR with an atomically dispersed Ni-N/C catalyst, the Faradaic efficiencies of CO (cathode) and 2,5-furandicarboxylic acid (FDCA, anode) exceeded 90.0 % under a low cell potential of 1.77 V.

Novel oxidative routes to N-arylpyridoindazolium salts.

A novel facile approach to N-arylpyridoindazolium salts is proposed, based on direct oxidation of the ortho-pyridine substituted diarylamines, either using bis(trifluoroacetoxy)iodobenzene as an oxidant, or electrochemically, via potentiostatic oxidation. Electrochemical synthesis occurs under mild conditions; no chemical reagents are required except electric current. Both approaches can be considered as a late-stage functionalization; easily available ortho-pyridyl-substituted diarylamines are used as the precursors.

Metal-free carbon nanotube boosted periodate oxidation towards organic pollutants: Identification of active sites and activation mechanism

Recent studies have indicated that metal-free carbon material-enhanced periodate (PI) oxidation is a promising strategy for mitigating organic pollution in water. However, the complicated physicochemical properties of carbon materials make it challenging to determine the activation mechanism and roles of the active sites. In this study, various metal-free carbon materials (GO, GP, ND, CNF, and MCNT) were used as catalysts for activating PI in the degradation of organic pollutants, with a focus on elucidating the underlying reaction mechanisms. All of these materials were found to be highly effective in PI activation, and MCNT showed the best catalytic performance. Quenching experiments and EPR results show that the MCNT/PI system primarily oxidizes organic contaminants via two non-radical oxidation routes as electron donors and electron mediators, respectively. Specifically, the oxygen-containing groups of MCNT (particularly carbonyl groups) play a crucial role in electron donation to enhance PI oxidation. Moreover, the structural defects of MCNT significantly accelerate electron transfer from the SIZ (target contaminant) to PI. These insights contribute to unveiling the activation of PI using metal-free carbon materials and hold substantial promise for advancing carbon-based catalysts in environmental cleanup efforts.

Nitrogen-Mediated Promotion of Cobalt-Based Oxygen Evolution Catalyst for Practical Anion-Exchange Membrane Electrolysis.

Scarce and expensive iridium oxide is still the cornerstone catalyst of polymer-electrolyte membrane electrolyzers for green hydrogen production because of its exceptional stability under industrially relevant oxygen evolution reaction (OER) conditions. Earth-abundant transition metal oxides used for this task, however, show poor long-term stability. We demonstrate here the use of nitrogen-doped cobalt oxide as an effective iridium substitute. The catalyst exhibits a low overpotential of 240 mV at 10 mA cm-2 and negligible activity decay after 1000 h of operation in an alkaline electrolyte. Incorporation of nitrogen dopants not only triggers the OER mechanism switched from the traditional adsorbate evolution route to the lattice oxygen oxidation route but also achieves oxygen nonbonding (ONB) states as electron donors, thereby preventing structural destabilization. In a practical anion-exchange membrane water electrolyzer, this catalyst at anode delivers a current density of 1000 mA cm-2 at 1.78 V and an electrical efficiency of 47.8 kW-hours per kilogram hydrogen.

Insights into the role of Mo in boosting CHx* oxidation for CO2 methane reforming

CHx* oxidation is one of the most vital routes to alleviate the carbon deposition problem of CO2 reforming of methane (DRM) reaction. Whereas, little experimental evidence has been observed on NiMo catalysts where the CHx* oxidation was dominant over its dissociation reaction. Herein, to experimentally unveil the CHx* oxidation route of NiMo catalysts, we design three catalysts with different particle sizes and structures. Among them, Mo/Niphy@SiO2 core shell catalyst demonstrated the dominant CHx* oxidation route over its dissociation based on in-situ diffuse reflectance infrared Fourier transform spectroscopy experiments. This was attributed to the confinement effect of SiO2 and the formation of Ni–Mo alloy, inhibiting the CHx* dissociation reaction. It exhibited relatively stable CH4 and CO2 conversions (77 % and 75 % respectively) within 180 h. By contrast, on Mo/Niphy catalyst which has a big Ni size, CHx* was mainly dissociated to C* and oxidized to CO which further underwent a disproportion reaction to produce CO2 and C*, leading to the severe carbon deposition and unstable DRM performance. The strategy to unveil the dominant role of CHx* oxidation via design catalysts with different sizes and structures sheds light on the study of reaction mechanism of other reactions.

Highly Selective Photocatalytic Synthesis of Acetic Acid at 0-25 °C.

Acetic acid (AA), a vital compound in chemical production and materials manufacturing, is conventionally synthesized by starting with coal or methane through multiple steps including high-temperature transformations. Here we present a new synthesis of AA from ethane through photocatalytic selective oxidation of ethane by H2O2 at 0-25 °C. The catalyst designed for this process comprises g-C3N4 with anchored Pd1 single-atom sites. In situ studies and computational simulation suggest the immobilized Pd1 atom becomes positively charged under photocatalytic condition. Under photoirradiation, the holes on the Pd1 single-atom of OH-Pd1 /g-C3N4 serves as a catalytic site for activating a C-H instead of C-C of C2H6 with a low activation barrier of 0.14 eV, through a concerted mechanism. Remarkably, the selectivity for synthesizing AA reaches 98.7 %, achieved under atmospheric pressure of ethane at 0 °C. By integrating photocatalysis with thermal catalysis, we introduce a highly selective, environmentally friendly, energy-efficient synthetic route for AA, starting from ethane, presenting a promising alternative for AA synthesis. This integration of photocatalysis in low-temperature oxidation demonstrates a new route of selective oxidation of light alkanes.

Highly Selective Photocatalytic Synthesis of Acetic Acid at 0‐25oC

Abstract Acetic acid (AA), a vital compound in chemical production and materials manufacturing, is conventionally synthesized by starting with coal or methane through multiple steps including high‐temperature transformations. Here we present a new synthesis of AA from ethane through photocatalytic selective oxidation of ethane by H2O2 at 0‐25°C. The catalyst designed for this process comprises g‐C3N4 with anchored Pd1 single‐atom sites. In‐situ studies and computational simulation suggest the immobilized Pd1 atom becomes positively charged under photocatalytic condition. Under photoirradiation, the holes on the Pd1 single‐atom of OH‐Pd1Å/g‐C3N4 serves as a catalytic site for activating a C‐H instead of C‐C of C2H6 with a low activation barrier of 0.14 eV, through a concerted mechanism. Remarkably, the selectivity for synthesizing AA reaches 98.7%, achieved under atmospheric pressure of ethane at 0°C. By integrating photocatalysis with thermal catalysis, we introduce a highly selective, environmentally friendly, energy‐efficient synthetic route for AA, starting from ethane, presenting a promising alternative for AA synthesis. This integration of photocatalysis in low‐temperature oxidation demonstrates a new route of selective oxidation of light alkanes.

Oxidation mechanism of anisole initiated by the hydroxyl radicals in the atmosphere

Anisole (C7H8O, AN), as a common industrial solvent and a promising renewable biofuel, could be a potential air pollutant. The atmospheric oxidation mechanism of AN in the gas phase, initiated by its reaction with the OH radical, is investigated here using quantum chemistry and chemical kinetics calculations. The reaction starts mainly by OH additions to the aromatic ring, with minor contribution from hydrogen atom abstraction from the methyl group. The fate of adducts AN-i-OH (Ri) (i = 1, 2 and 4) is investigated here. Calculations show that R1 decomposes predominantly to phenol and CH3O while adduct R2 reacts dominantly with O2 by hydrogen-atom abstraction to form 2-methoxyphenol. The mechanism suggests that the dominant oxidation routes do not require the participation of NOx and therefore would not lead to significant ozone formation. The main products in the gas phase are the ring-retaining compound phenol and 2-methoxyphenol, which should be the intermediate compounds for formation of high oxygenated molecules (HOMs).

Surface oxidation of α-Ni(OH)2 nanowires to boost energy storage capability for supercapacitors

Nickel hydroxide is a remarkable battery-like material for supercapacitors. However, it often suffers from low actual capacity and inferior cyclic performance. Herein, we introduce a surface oxidation route to prepare coaxial α-nickel hydroxide@nickel oxide nanowires (α-NHO@NO NWs) from α-nickel hydroxide nanowires (α-NHO NWs) obtained by hydrothermal synthesis. The α-NHO@NO NWs have a large specific surface of 85.4 m2 g−1 with hierarchical mesopores. Compared to α-NHO NWs, the energy storage capacity of α-NHO@NO NWs is significantly enhanced. In a 3-electrode system, the α-NHO@NiO NWs delivered 551.8 C g−1 at 0.25 A g−1. In addition, an assembled α-NHO@NO//AC hybrid supercapacitor (HSC) provided a solid gravimetric capacity of 95.6 F g−1 at 0.5 A g−1, exceptional rate capability, and robust cyclic performance (80.4 % retention after 15,000 cycles). The α-NHO@NO//AC device supplied 34.0 Wh kg−1 at 400 W kg−1 and 20.1 Wh kg−1 at 8000 W kg−1. In addition, a homemade α-NHO@NO//AC device successfully powered a micro-fan, demonstrating its potential for real-world applications. The outstanding charge storage capability of α-NHO@NO NWs can be attributed to their unique coaxial nanowire-like structure, large specific surface, and hierarchical mesopores.

Sepiolite-Supported Manganese Oxide as an Efficient Catalyst for Formaldehyde Oxidation: Performance and Mechanism.

The current study involved the preparation of a number of MnOx/Sep catalysts using the impregnation (MnOx/Sep-I), hydrothermal (MnOx/Sep-H), and precipitation (MnOx/Sep-P) methods. The MnOx/Sep catalysts that were produced were examined for their ability to catalytically oxidize formaldehyde (HCHO). Through the use of several technologies, including N2 adsorption-desorption, XRD, FTIR, TEM, H2-TPR, O2-TPD, CO2-TPD, and XPS, the function of MnOx in HCHO elimination was examined. The MnOx/Sep-H combination was shown to have superior catalytic activities, outstanding cycle stability, and long-term activity. It was also able to perform complete HCHO conversion at 85 °C with a high GHSV of 6000 mL/(g·h) and 50% humidity. Large specific surface area and pore size, a widely dispersed active component, a high percentage of Mn3+ species, and lattice oxygen concentration all suggested a potential reaction route for HCHO oxidation. This research produced a low-cost, highly effective catalyst for HCHO purification in indoor or industrial air environments.