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Two new supramolecular photocatalysts made of covalently linked Ru(II) polypyridine chromophore subunits ([Ru(bpy)3]2+-type species; bpy = 2,2′-bipyridine) and [RuL(pic)2] (L = 2,2′-bipyridine-6,6′-dicarboxylic acid; pic = 4-picoline) water oxidation catalyst subunits have been prepared. The new species, 1 and 2, contain chromophore and catalyst subunits in the molecular ratios 1:1 and 1:2, respectively. The model chromophore species [Ru(bpy)2(L1)]2+ (RuP1; L1=4-[2-(4-pyridyl)-2-hydroxyethyl]-4-methyl-2,2′-bipyridine) and [Ru(bpy)2(L2)]2+ (RuP2; L2 = 4,4′-bis[2-(4-pyridyl)-2-hydroxyethyl]-2,2′-bipyridine) have also been prepared. The absorption spectra, oxidation behavior, and luminescent properties of 1 and 2 have been studied, and the results indicate that each subunit largely maintains its own properties in the supramolecular species. However, the luminescence of the chromophore subunits is significantly quenched in 1 and 2 in comparison with the luminescence of the respective model species. Both 1 and 2 exhibit catalytic water oxidation in the presence of cerium ammonium nitrate, exhibiting an I2M mechanism, with a better efficiency than the known catalyst [RuL(pic)2] under the same experimental conditions. Upon light irradiation, in the presence of persulfate as a sacrificial acceptor agent, 1 and 2 are more efficient photocatalysts than a system made of separated [Ru(bpy)3]2+ and [RuL(pic)2] species, highlighting the advantage of using multicomponent, supramolecular species with respect to isolated species. The O–O bond formation step is I2M, even in the photo-driven process. The photocatalytic process of 2 is more efficient than that of 1, with the turnover frequency reaching a value of 1.2 s−1. A possible reason could be an increased local concentration of catalytic subunits in the needed bimolecular assembly required for the I2M mechanism in 2 with respect to 1, a consequence of the presence of two catalytic subunits in each multicomponent species 2. [ABSTRACT FROM AUTHOR]

Three novel organic–inorganic polyoxoniobate-based compounds modified with Cu(II) amine complexes were synthesized under hydrothermal conditions with the chemical formulas as follows: K0.5[Cu(enMe)2]4[K0.5SiNb12O40(VO)4.25](OH)1.5·9H2O (1), K0.5[Cu(enMe)2]4[K0.5H2PNb12O40(VO)2]·12.5H2O (2), and K0.5[Cu(enMe)2]4[K0.5H2VNb12O40(VO)2]·12.5H2O (3) (enMe = 1,2-diaminopropane). These compounds were characterized by single crystal X-ray diffraction, infrared spectroscopy (IR), UV-Vis spectroscopy, elemental analysis and powder X-ray diffraction (PXRD) analysis. Notably, while these three compounds exhibit identical cell parameters, they possess distinct stoichiometric compositions and differing polyoxometalate building block structures. Typically, compounds with the same cell parameters are classified as isostructural, sharing identical structures with only minor elemental variations in their compositions. To the best of our knowledge, compounds 1–3 represent the first instances of compounds that share the same cell parameters yet are not isostructural. In this study, we not only synthesized these three compounds and thoroughly examined the differences in their structures and properties, but also investigated their catalytic performances as catalysts for the oxidation of styrene. [ABSTRACT FROM AUTHOR]

A lanthanum silicate La9.33Si6O26 (LSO) crystallizes in an apatite-type structure and has been known as a promising oxide-ion conductor. Here, we report the activity of LSO for catalytic partial oxidation of methane (CPOX) to synthesis gas. The LSO catalyst demonstrated relatively high catalytic activity from 500 to 700 °C, with CH4 conversion reaching 22.1% at 700 °C while retaining moderate CO and H2 selectivities of 20–60%. Notably, LSO exhibited higher CPOX activity than non-apatite-type La2SiO5 despite their similar specific surface areas. The higher CPOX activity of LSO is likely attributed to its structural superiority involving mobile oxide ions in the crystal structure. The reaction kinetic study showed that the reaction orders for methane and oxygen in the CPOX reaction over the LSO catalyst were 0.69–0.73 and 0.08–0.21, respectively. Furthermore, the small contribution of adsorbed O species generated from gas-phase O2 molecules indicated that the lattice oxygen may be involved in the reaction mechanism. The kinetic isotope effect (KIE) study using a CD4 suggested that C–H bond breaking is the rate-determining step of CPOX over LSO. [ABSTRACT FROM AUTHOR]

In this work, it was found that organotin-functionalized tungstophosphates PW9-TM-SnRCOO and P2W15-TM-SnRCOO (PW9 = [PW9O34]9−; P2W15 = [P2W15O56]12−; TM = Mn, Co, Zn; R = CH2CH2) exhibited mimicking horseradish peroxidase (HRP) activity, with the catalytic activity of PW9-TM-SnRCOO being higher than that of P2W15-TM-SnRCOO. Among the polyoxometalates (POMs), those containing Zn ions demonstrated the highest catalytic activity. Furthermore, a recyclable POM-based ZIF-nanocomposite, Na8K2[Zn2{Sn(CH2)2COO}2(B-α-PW9O34)2]·13H2O@ZIF-67 (PW9-Zn-SnRCOO@ZIF-67), was designed and synthesized using a convenient one-step method at room temperature. As a mimic enzyme of HRP for the catalytic oxidation of o-phenylenediamine (OPD), PW9-Zn-SnRCOO@ZIF-67 exhibited enhanced catalytic activity and anti-interference ability. Moreover, the introduction of the POM-estertin derivative significantly improved the acid resistance of ZIF-67. PW9-Zn-SnRCOO@ZIF-67 can be further used as a colorimetric sensor material for the detection of acetone with a wide linear range (0.01–4.0 mM), a low detection limit (0.0074 mM), and good reusability. These results demonstrate that organotin-functionalized POMs@ZIFs, as a new class of non-enzymatic sensor materials, have wide application prospects for the detection of acetone in real water samples. [ABSTRACT FROM AUTHOR]

The high activity and high selectivity in the catalytic oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA) under non-alkaline conditions has always been a significant challenge in the field of biomass utilization. In this work, a thermodynamically stabilized high-entropy alloy (HEA) structure with relatively low Pt content was synthesized via a simple impregnation–calcination procedure by tuning the mixing enthalpy and the Gibbs free energy of the metal-mixing system. The prepared HEA shows excellent catalytic performance in the aerobic oxidation of HMF into FDCA under base-free conditions. Experiments and DFT calculations revealed that molecular O2 can be easily activated into highly oxidative hydroxyl radicals (˙OH) in the presence of water over the HEA surface, and facilitates the oxidation of HMF to FDCA under base-free conditions. This work provides a valuable reference for similar aerobic oxidation processes in which alkaline promoters and noble metal catalysts are needed. [ABSTRACT FROM AUTHOR]

The high catalytic activity of Cu-based nanozymes mainly depends on the efficient Fenton-like reaction of Cu+/ H2O2, but Cu+ cannot exist stably. Trying to find a material that can stably support Cu+ while promoting the electron cycle of Cu2+/Cu+ still faces serious challenges. C60 is expected to be an ideal candidate to solve this problem due to its unique structure and rich physicochemical properties. Here, we designed and synthesized a C60-doped Cu+-based nanozyme (termed as C60-Cu-Bpy) by loading high catalytic active site Cu+ onto C60 and coordinating with 2,2′-bipyridine (Bpy). The single crystal diffraction analysis and a series of auxiliary characterization technologies were used to demonstrate the successful preparation of C60-Cu-Bpy. Significantly, the C60-Cu-Bpy exhibited superior peroxidase-like activity during the catalytic oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB). Then, the catalytic mechanism of C60-Cu-Bpy as peroxidase was elucidated in detail, mainly benefiting from the dual function of C60. On the one hand, C60 acted as a carrier to directly support Cu+, which has the ability to efficiently decompose H2O2 to produce reactive oxygen species. The other was that C60 acted as an electron buffer, contributing to promoting the Cu2+/Cu+ cycle to facilitate the reaction. Furthermore, a colorimetric sensor for the quantitative analysis of bleomycin was established based on the principle of bleomycin specific inhibition of C60-Cu-Bpy peroxidase-like activity, with satisfactory results in practical samples. This study provides a new strategy for the direct synthesis of Cu+-based nanozymes with high catalytic performance. Schematic illustration of the preparation of C60-Cu-Bpy (a) and the colorimetric detection of bleomycin based on specific inhibition of C60-Cu-Bpy peroxidase-like activity (b) [ABSTRACT FROM AUTHOR]

Persistent phosphors possess unique afterglow optical properties. In this paper, a class of ultra-violet (UV) persistent luminescence nanoparticles were developed for catalytic photodegradation applications. UV persistent luminescence nanoparticles of SiO 2 -Zn 2 SiO 4 :Ga and SiO 2 -Zn 2 SiO 4 :Ga,Pb were successfully synthesized by using a mesoporous template method. The UV persistent luminescence intensity of SiO 2 -Zn 2 SiO 4 :Ga at 405 nm was enhanced up to ca. 3.5 times by co-doping with Pb2+ (396 nm), along with longer persistent luminescence duration. The photodegradation results indicate that it is useful to introduce UV persistent luminescence property into SiO 2 -Zn 2 SiO 4 :Ga,Pb to obtain enhanced catalytic activity of SiO 2 -Zn 2 SiO 4 with a bigger catalytic oxidation reaction kinetic constant (up to ∼4 times). This kind of UV persistent catalysis strategy may become a potential feasible method for better catalytic photodegradation activity. The UV persistent photocatalyst has potential applications in the photooxidation of organic molecules in high chroma and/or turbidity aqueous systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe-NC-Se demonstrates good resistance to flue gas interference. • Fe-NC-Se exhibits atomically dispersed active sites essential for selenium doping and preferential Hg0 adsorption. • Optimal Fe-NC-Se demonstrates an over 2.5-fold enhancement in Hg0 oxidation capacities compared to raw selenium-free Fe-NC. • Fe-NC-Se showcases high reusability and sustains its catalytic activity. This study developed a novel selenium-doped metal nitride carbon, Fe-NC-Se, via pyrolysis and impregnated hydrothermal methods for elemental mercury removal from coal-fired flue gas. The Fe-NC-Se demonstrated a remarkable mercury removal performance, achieving an average efficiency of 96.98% within 60 min at an optimal Se/Fe ratio of 2:1 and temperature of 110 °C, which was 2.5 times higher than that of the pristine Fe-NC (iron nitride carbon). Notably, Fe-NC-Se maintained an 84% efficiency in a high SO 2 environment (1600 ppm), indicating strong resistance to SO 2 poisoning. Long-term testing over 24 h showed a consistent removal efficiency of 84.75%, suggesting potential for recyclability. Advanced characterization techniques, including TEM (transmission electron microscopy) and XPS (X-ray photoelectron spectrometer), along with Density Functional Theory calculations, were employed to explore the removal mechanism. Results indicated that selenium doping enhanced surface charge transfer and the reactivity of surface atoms, facilitating mercury oxidation and sequestration. The oxidized Hg2+ was anchored by Se and partially stabilized by C, N, and Fe atoms, enhancing the catalyst's effectiveness. This work not only advances the design of mercury abatement catalysts but also supports the industrial applicability of Fe-NC-Se in flue gas treatment. [ABSTRACT FROM AUTHOR]

This review systematically evaluates the research and applications of metal mesh‐based catalysts for CO oxidation. CO is a hazardous gas that affects human health and the environment. Traditional cordierite‐based catalysts have drawbacks such as complex preparation, high costs, poor stability, and limited catalytic activity, necessitating exploration of alternative solutions. Monolithic metal mesh‐based catalysts, using metal substrates like Ti, Cu, Fe, FeCrAl, stainless steel, Al and Ni, could address these problems effectively. Generally, each metal mesh requires specific pretreatments to roughen surface and facilitate the loading of active species. Plasma electrolytic oxidation is particularly effective for Ti and Al mesh. This results in a monolithic metal mesh‐based catalyst with uniform surface distribution and fully exposed active species. The review also summarizes in‐situ preparation strategies for metal mesh‐based catalysts and their progress in CO oxidation. Finally, the development potential of metal mesh‐based catalysts is discussed, emphasizing the significant challenges and future prospects for industrial applications. [ABSTRACT FROM AUTHOR]

The "storage‐oxidation" cycle is an energy‐efficient process for removing low‐concentration volatile organic compounds (VOCs). However, due to the weak interaction between BTX compounds (benzene, toluene, and xylene) and commonly used adsorbent materials, how to prevent the BTX escape prior to oxidation remains a challenge. In this work, a comprehensive study on the critical factors influencing on the "storage‐oxidation" cycling removal of BTX are investigated. The study elucidated the relationship between different zeolites and their capacity for storing BTX. It was found that the adsorption of BTX onto various zeolites is greatly impacted by the pore size of the zeolite and the volatility of BTX. Particularly, toluene and/or m‐xylene could be preferential adsorbed by Cu2+ located on the ion‐exchange sites, forming strong bonding interactions that facilitating the in‐situ thermal regeneration. Furthermore, the experimental results suggest that a synergy between Cu2+ and CuO could accelerate the catalytic oxidation of BTX. These findings offer valuable insights for designing bifunctional catalysts for the "storage‐oxidation" cycling removal of BTX. [ABSTRACT FROM AUTHOR]

Singlet oxygen (1O2) has attracted great attention owing to its superior comprehensive oxidizing performance and extensive application in dealing with ever‐growing environmental pollution. However, the efficient catalytic generation of 1O2 is very challenging due to the low catalytic activity of most catalysts and the generation of oxygen‐containing radicals in the catalytic reaction. Herein, C‐doped Co nanoparticles (CoNPs) supported on porous carbon (C─Co/C) as highly reactive and selective 1O2‐producing catalysts are demonstrated for efficient catalytic oxidation of recalcitrant organics via activation of peroxymonosulfate (PMS). The doped C 2p orbitals can accept Co 3d electrons, thereby weakening the Co─O bonding between Co and PMS or other oxygen‐containing intermediates such as *SO4, *OH, *OOH, and *O. The adsorption and cleavage energy of PMS on Co nanoparticle is reduced from 8.09 to 4.64 eV by C doping. The energy barrier of the *OOH to 1O2 step is also lowered significantly, thereby kinetically improving the activity for the generation of 1O2. The C─Co/C catalysts promotes the efficient and 100% selective generation of 1O2 with high modified kinetic model (K) values of 457.0 and 94.5 µmol s−1 g−1 for rhodamine (RhB) and 2,4‐dichlorophenol (2,4‐DCP), respectively. [ABSTRACT FROM AUTHOR]

Introduction: Volatile organic compounds (VOCs) have attracted widespread attention due to their adverse effects on human health. Photocatalytic oxidation is an effective technology for degrading VOCs under ambient conditions. Methods: In order to better understand the trends and development of global trends in photocatalytic oxidation of VOCs, the analysis of 2493 articles or reviews from the Science Citation Index Expanded (SCIE) in the Web of Science Core Collection, covering the period from 1998 to 2023, was conducted using CiteSpace and VOSviewer software. Results and Discussion: The findings indicate significant growth in papers concerning photocatalytic oxidation of VOCs. China emerges as the most active country among the main drivers. Principal sources publishing relevant research are Applied Catalysis B-Environmental, Chemical Engineering Journal, Journal of Hazardous Materials, and Environmental Science and Technology. A relatively well-established theoretical framework has been developed for the study of photocatalytic oxidation of VOCs. In the field of VOCs photocatalytic oxidation, the focus is on the development and optimization of advanced photocatalysts with efficient charge separation, better adsorption performance, and a wider light response range. In addition, the in-depth study of the charge generation and transfer mechanisms within the photocatalysts, as well as the comprehensive understanding of the reaction kinetics and catalytic oxidation process, the optimization of the reaction conditions, and the improvement of the catalytic efficiency are at the forefront of the research in this field. This research system is advancing and becoming more refined, with its theoretical propositions, research findings, and methodologies increasingly employed and confirmed. [ABSTRACT FROM AUTHOR]

Large‐scale hydrogen production through water splitting represents an optimal approach for storing sustainable but intermittent energy sources. However, water oxidation, a complex and sluggish reaction, poses a significant bottleneck for water splitting efficiency. The impact of outer chemical environments on the reaction kinetics of water oxidation catalytic centers remains unexplored. Herein, chemical environment impacts were integrated by featuring methylpyridinium cation group (Py+) around the classic Ru(bpy)(tpy) (bpy=2,2'‐bipyridine, tpy=2,2′ : 6′,2′′‐terpyridine) water oxidation catalyst on the electrode surface via electrochemical co‐polymerization. The presence of Py+ groups could significantly enhance the turnover frequencies of Ru(bpy)(tpy), surpassing the performance of typical proton acceptors such as pyridine and benzoic acid anchored around the catalyst. Mechanistic investigations reveal that the flexible internal proton acceptor anions induced by Py+ around Ru(bpy)(tpy) are more effective than conventionally anchored proton acceptors, which promoted the rate‐determining proton transfer process and enhanced the rate of water nucleophilic attack during O−O bond formation. This study may provide a novel perspective on achieving efficient water oxidation systems by integrating cations into the outer chemical environments of catalytic centers. [ABSTRACT FROM AUTHOR]

2,5‐Furandicarboxylic acid (FDCA) is a biomass‐derived monomer for the production of poly(ethylene 2,5‐furandicarboxylate) (PEF), which is a novel polyester that can serve as a sustainable alternative to traditional petroleum‐based poly(ethylene terephthalate) (PET). Currently, the industrial production of FDCA depends on the thermo catalytic aerobic oxidation of 5‐hydroxymethylfurfural (HMF) using heterogeneous catalysts in aqueous solution, in which process equivalent homogeneous bases are usually needed to promote the oxidation of hydroxymethyl and aldehyde groups and simultaneously improve the solubility of oxidative products via forming carboxylate. The involvement of massive base causes risks of equipment corrosion and necessitates subsequent product separation and purification with a large amount acid. In this context, the base‐free aerobic oxidation of HMF to FDCA has attracted much concern. Nowadays, by developing supported catalysts with multiple catalytic sites, using diluted substrate and finding good solvent for FDCA, much progress has been achieved in this field. This review provides the state of the art of the heterogeneous catalysis for aerobic oxidation of HMF to FDCA under base‐free conditions, highlighting the catalytic mechanism to shed light on the catalyst design principles. [ABSTRACT FROM AUTHOR]

Aiming at the problem of the poor performance of an Mn-MOF-74-derived Mn3O4 catalyst in low-temperature carbon monoxide (CO) oxidation, copper (Cu) and cerium (Ce) elements were used to modify the Mn3O4 catalyst to improve its performance in low-temperature CO oxidation. According to the results of catalytic performance testing, the CO oxidation activity of the Cu0.3Mn2.7O4 catalyst was significantly improved compared with that of the pristine Mn3O4 catalyst, when a CO conversion rate of 90% was achieved at 118 °C. According to X-ray photoelectron spectroscopy and Brunauer–Emmett–Teller analyses, the (Mn2+ + Mn3+)/(Mn2+ + Mn3+ + Mn4+) ratio and the Oads/Ototal ratio increased after Cu doping, indicating promoted oxygen vacancy generation. In addition, the increased specific surface area was beneficial for the adsorption of reactant molecules and the exposure of active sites. According to H2-temperature-programmed reduction characterization, Cu doping significantly enhanced the performance of the Cu0.3Mn2.7O4 catalyst during low-temperature redox. Finally, these factors synergistically promoted the degradation of CO over the Cu0.3Mn2.7O4 catalyst. In addition, operando diffuse reflectance Fourier transform infrared spectroscopy results suggested the presence of more terminal-type oxygen, which is essential for the catalytic oxidation of CO on the surface of the Cu0.3Mn2.7O4 catalyst. Moreover, the Cu0.3Mn2.7O4 catalyst also showed excellent resistance to carbonate, and remarkable stability. [ABSTRACT FROM AUTHOR]

Oxidative transformation of phenols is an efficient route towards the production of moieties for naturally occurring quinones with a wide range of biological activities. Silica supported Ru−Bi catalysts were prepared by microwave‐assisted loading (MW) and deposition (DP) methods. The as‐prepared catalysts were characterized by XRD (X‐ray diffraction), N2 physisoption, SEM (Scanning electron microscopy), TEM (Transmission electron microscopy) and XPS (X‐ray photoelectron spectrometry) techniques. Catalysts with low Bi loading, 5 %Ru‐1 %Bi, have narrow particle size distributions that correspond to an average particle size of 2.21–2.59 nm. 5 %Ru‐5 %Bi catalysts consist of Ru−Bi nanochains. The outcome of the catalytic oxidation of 2,3,5‐trimethylhydroquinone (TMHQ, 1) to 2,3,5‐trimethyl‐1,4‐benzoquinone (TMBQ, 2) depends on the catalyst preparation method, promoter loading, solvent and temperature used. MW‐5Ru1Bi is the most active catalyst with conversions that range between 99–100 % at both room temperature (r.t) and under refluxing MeNO2 and MeOH. The highest yields of TMBQ (100 %) were obtained over MW‐5 %Ru‐1 %Bi and DP‐5 %Ru‐5 %Bi catalysts. [ABSTRACT FROM AUTHOR]

Atomic-scale structures that account for the acceleration of reactivity by heterogeneous catalysts often form only under reaction conditions of high temperatures and pressures, making them impossible to observe with low-temperature, ultra-high-vacuum methods. We present velocity-resolved kinetics measurements for catalytic hydrogen oxidation on palladium over a wide range of surface concentrations and at high temperatures. The rates exhibit a complex dependence on oxygen coverage and step density, which can be quantitatively explained by a density functional and transition-state theory-based kinetic model involving a cooperatively stabilized configuration of at least three oxygen atoms at steps. Here, two oxygen atoms recruit a third oxygen atom to a nearby binding site to produce an active configuration that is far more reactive than isolated oxygen atoms. Thus, hydrogen oxidation on palladium provides a clear example of how reactivity can be enhanced on a working catalyst. [ABSTRACT FROM AUTHOR]

A series of Co–M (M = Mn, Ce, Cu) bimetallic oxide catalysts were prepared by a modified solvent pyroalcoholysis method, and the performance in the catalytic oxidation of toluene was investigated. The experimental results showed that the conversion rate of the as-prepared Co1Cu1 catalyst performed a 50% conversion (T50) and 90% conversion (T90) in toluene oxidation at 211 °C and 241 °C, respectively. A series of the characterization demonstrated that the performance improvement is attributable to the Co1Cu1 catalyst owning high Co3+ concentration (Co3+/Co2+ = 1.14), abundant surface adsorbed oxygen (Oads/O = 67.33%), and excellent low temperature reducibility. Interestingly, these properties promoted the adsorption and deep oxidation of toluene molecules. Concurrently, the XRD and Raman characterizations verified that the spinel structure of Co3O4 is altered by Cu doping, producing high-valence surface active Co species and numerous lattice defects that increased the catalyst's catalytic efficiency. This study showed that creating defect sites by metal doping is a useful strategy for improving Co3O4 spinel's catalytic activity. [ABSTRACT FROM AUTHOR]

Ru/HAP catalyst with high-dispersion is prepared by a novel homogeneous deposition precipitation method (DPU). As compared to the conventional impregnation method (IM), the catalytic oxidation performance for toluene and DCM are much higher for DPU-sample with higher activity and good stability in humid air. Characterizations reveal that DPU-sample has a larger surface area with mesoporous structure, keeping smaller Ru particle size and uniform distribution on HAP, which is favorable for the exposure of active sites. The preparation and reaction conditions were also systematically studied, showing that 0.5 Ru/HAP(500)-DPU sample is a promising catalyst for VOC and CVOC removal. The Ru/HAP (DPU) is a promising broad-spectrum catalyst for VOC and CVOC removal. [ABSTRACT FROM AUTHOR]

The emission of CO in sintering flue gas contributes to environmental pollution and energy wastage. Achieving full oxidation of CO presents a viable strategy for elevating the sintering flue gas temperature by over 50°C, thereby significantly reducing energy consumption during the heating of flue gas in NH3-SCR denitrification systems. In this work, MnCeOx catalysts were synthesized under various conditions, including different calcination temperatures, durations, and molar ratios. Their catalytic activity and resistance to H2O were evaluated under simulated sintering flue gas conditions at different temperatures. Our findings indicated that the M8C1 catalyst exhibited exceptional activity, achieving CO conversion rates exceeding 95% within 125–250°C. However, the catalytic activity experienced a notable decline during the H2O resistance test at 150°C, while remaining unaffected at 250°C. Investigating the inhibition mechanism of H2O on CO oxidation at varying temperatures through H2-TPR, O2-TPD, and in situ DRIFTS. At lower temperatures (150°C), CO and O2 adsorption on the catalyst surface led to the formation of CO2, with O2 adsorption exerting a more significant influence on activity, consistent with the Langmuir–Hinshelwood mechanism. Introduction of H2O into the flue gas resulted in the formation of OH−, which competed with CO and O2 for adsorption on the catalyst surface, thereby diminishing catalyst oxidation activity due to competitive adsorption hindering CO and O2 adsorption. Conversely, at higher temperatures (250°C), the reaction process between CO and lattice oxygen to produce CO2 followed the Mars-van Krevelen mechanism. Notably, at these temperatures, no adsorbed OH− were detected on the catalyst surface, leaving the activity unaffected. Based on our research, employing the MnCeOx catalyst during the high-temperature stage in conjunction with the NH3-SCR catalyst is recommended for enhanced CO oxidation efficiency in sintering flue gas treatment processes. [ABSTRACT FROM AUTHOR]

For the direct alkaline oxidation of rice husk lignin, we developed a copper foam-based heterogeneous catalyst that offers advantages in its recovery after the reaction mixture. The depolymerized products were utilized for muconate production by an engineered Pseudomonas sp. NGC7-based strain. A hydroxide nanorod-modified copper foam was prepared by the surface oxidation of copper foam, followed by alkaline oxidation of rice husk lignin over the catalyst. The catalyst was easily separated from the cellulosic residues in the reaction mixture, and the residues were then recovered by filtration. The resulting lignin stream was composed of a variety of aromatic monomers containing p -hydroxyphenyl, guaiacyl, and syringyl compounds. The catabolic activity of Pseudomonas sp. NGC7 was demonstrated to be more suitable for muconate production from a mixture comprising 4-hydroxybenzoate (a typical p -hydroxyphenyl compound), vanillate (a guaiacyl compound), and syringate (a syringyl compound), owing to its natural ability to grow on syringate. Thus, it was applied to produce muconate from a rice husk lignin stream prepared through hydroxide nanorod-modified copper foam-catalyzed alkaline oxidation by conferring the genes responsible for converting the acetophenone derivatives to their corresponding aromatic acids and protocatechuate decarboxylase to an NGC7-based strain deficient in protocatechuate 3,4-dioxygenase and muconate cycloisomerase. As a result, the engineered NGC7-based muconate-producing strain produced muconate selectively from the rice husk lignin stream at 93.7 mol% yield. • A hydroxide nanorod-modified copper foam [Cu(OH) 2 /CF] was prepared. • Cu(OH) 2 /CF was used for the alkaline oxidation of rice husk lignin. • Cu(OH) 2 /CF was advantageous in separation from the cellulosic residues. • Pseudomonas sp. NGC7-based strain was useful for muconate production. [ABSTRACT FROM AUTHOR]

Flooding and drainage of paddy fields can induce the activation of soil cadmium (Cd)/arsenic (As), which will accumulate in rice grains and threaten human health. Mn oxides influence soil Cd and As availability, but few detailed studies have been reported on how Mn redox simultaneously affects Cd and As mobility during flooding and drainage. Two paddy soils with various Mn contents were incubated under three redox conditions, namely 30-d reduction, 30-d oxidation and 20-d reduction subsequent with 10-d oxidation, to investigate Cd and As migration. During reduction, the soil abundant in native Mn oxides possessed more high-valence Mn oxides, which promoted As oxidation and retarded the reductive dissolution of Fe (oxyhydro)oxides, thereby decreasing As mobility. Cd mobility mainly depended on the conversion between Fe-Mn oxides-bound Cd and exchangeable Cd. The high Mn content was conducive to decreasing Cd mobilization. Furthermore, the oxidation of As in soils was linked with a Fenton-like effect. The generated hydroxyl radicals (•OH) decreased with oxidation and the oxidation of Mn(II) by •OH inhibited As migration but promoted Cd activation. In summary, the mobility of Cd and As was lower in Mn rich soils, which may involve the immobilization, oxidation and catalytic effects of Mn oxides. HIGHLIGHTS: Cd mobility mainly relied on the conversion between Fe-Mn oxides-bound Cd and exchangeable Cd. The redox dependence of Mn played a key role in controlling Cd and As migration in paddy soils. Soils containing higher content of Mn oxides possessed lower mobility of Cd and As. The oxidative effect of •OH on Mn(II) inhibited As mobility but promoted Cd activation. [ABSTRACT FROM AUTHOR]

• The start-up of filters for NH 4 + and Mn2+ removal by catalytic oxidation was studied. • Different combinations of oxidants and reductants were introduced during the start-up period. • Comparison of catalytic oxidation activity of MnOx follows: Mn7+→MnO x ˃Mn7+→MnO x ←Mn2+ ˃ Mn2+→MnO x. • Potassium permanganate was more conducive to the formation of active species. A pilot-scale filtration system was adopted to prepare filter media with catalytic activity to remove manganese (Mn2+) and ammonium (NH 4 +-N). Three different combinations of oxidants (KMnO 4 and K 2 FeO 4) and reductants (MnSO 4 and FeCl 2) were used during the start-up period. Filter R3 started up by KMnO 4 and FeCl 2 (Mn7+→MnO x) exhibited excellent catalytic property, and the NH 4 +-N and Mn2+ removal efficiency reached over 80% on the 10th and 35th days, respectively. Filter R1 started up by K 2 FeO 4 and MnSO 4 (MnO x ←Mn2+) exhibited the worst catalytic property. Filter R2 started up by KMnO 4 and MnSO 4 (Mn7+→MnO x ←Mn2+) were in between. According to Zeta potential results, the Mn-based oxides (MnO x) formed by Mn7+→MnO x performed the highest pH IEP and pH PZC. The higher the pH IEP and pH PZC , the more unfavorable the cation adsorption. However, it was inconsistent with its excellent Mn2+ and NH 4 +-N removal abilities, implying that catalytic oxidation played a key role. Combined with XRD and XPS analysis, the results showed that the MnO x produced by the reduction of KMnO 4 showed early formation of buserite crystals, high degree of amorphous, high content of Mn3+ and lattice oxygen with the higher activity to form defects. The above results showed that MnO x produced by the reduction of KMnO 4 was more conducive to the formation of active species for catalytic oxidation of NH 4 +-N and Mn2+ removal. This study provides new insights on the formation mechanisms of the active MnO x that could catalytic oxidation of NH 4 +-N and Mn2+. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • High dispersion of active Cu has been loaded on Al 2 O 3 surface. • The well-dispersed active Cu nanoparticles on Al 2 O 3 has up to 20 wt% loads. • The activity of Cu/Al 2 O 3 exhibits a clear linear correlation with the Cu0 content on Al 2 O 3. • This result confirms that Cu0 plays a crucial role in CO oxidation of Cu/Al 2 O 3 , not Cu+ or Cu2+. Catalytic oxidation of carbon monoxide (CO) by Cu/Al 2 O 3 has garnered increasing interest in recent years due to its promising application prospects. Numerous investigations conducted on the Cu/Al 2 O 3 system, but its catalytic performance for CO oxidation is still not as promising as that of precious metal catalysts. Increasing the loading amount of the active Cu on Al 2 O 3 surface is a feasible method for improving its activity. However, with the increase of Cu loading, the agglomeration and enlargement of Cu particles is inevitable, which reduces the active Cu amount. Therefore, the utilization rate of Cu atoms is not high and the catalytic performance often can not further rise. Enhancing active Cu loading amount as high as possible is a prerequisite to further enlarge the activity of Cu/Al 2 O 3 catalyst. Herein, self-synthesized Al 2 O 3 nanofibers (Al 2 O 3 -nf) with high specific surface area and abundant penta-coordinated aluminum (Al V) are used as the support to maximize the Cu loading amount by chemical vapor deposition (CVD). And commercially available α-Al 2 O 3 is used for comparative experiment. The high specific surface area could make Cu high dispersion on Al 2 O 3 , even at 20 wt% Cu loads, which is beneficial to high concentration load of active Cu. The catalytic activity of Cu/Al 2 O 3 -nf-CVD gradually increases with the increase of Cu loading from 2 wt% to 20 wt%, exhibiting a clear linear correlation with the surface content of Cu0 on the catalyst. Meanwhile, this result confirms that Cu0 plays a crucial role in CO oxidation of Cu/Al 2 O 3. However, commercial α-Al 2 O 3 reaches its highest activity when the Cu load is 5%, and then its activity begins to decrease due to the agglomeration of particles. Moreover, Cu/Al 2 O 3 -nf-CVD also exhibits remarkable thermal stability for CO oxidation. This work highlights a new strategy to synthesis of high Cu loading amount, high activity and thermostable Cu/Al 2 O 3 catalyst for low-temperature oxidation of CO. [ABSTRACT FROM AUTHOR]

[Display omitted] • MnO X catalysts with tunable morphology and oxygen vacancy defects were prepared. • Tailoring the morphology of MnO X can greatly improve the catalytic activity. • The oxygen vacancy defect on MnO X can expedite the activation-oxidation of toluene. To clarify the key role of oxygen vacancy defects on enhancing the oxidative activity of the catalysts, metal–organic frameworks (MOFs) derived MnO X catalysts with different morphologies and oxygen vacancy defects were successfully prepared using a facile in-situ self-assembly strategy with different alkali moderators. The obtained morphologies included three-dimensional (3D) triangular cone stacked MnO X hollow sphere (MnO X -H) and 3D nanoparticle stacked MnO X nanosphere (MnO X -N). Compared to MnO X -N, MnO X -H exhibited higher activity for the oxidation of toluene (T 90 = 226 °C). This was mainly due to the large number of oxygen vacancy defects and Mn4+ species in the MnO X -H catalyst. In addition, the hollow structure of MnO X -H not only facilitated toluene adsorption and activation of toluene and also provided more active sites for toluene oxidation. Reaction mechanism studies showed that the conversion of toluene to benzoate could be realized over MnO X -H catalyst during toluene adsorption at room temperature. In addition, abundant oxygen vacancy defects can accelerate the activated oxidation of toluene and the formation of oxidation products during toluene oxidation. [ABSTRACT FROM AUTHOR]

The selective oxidation of hydrocarbons can be used to produce oxygen-containing functional compounds such as alcohols, aldehydes or ketones and its efficient and green conversion lies in the development of efficient catalysts that activate C-H bonds and O2 simultaneously. In this work, the bimetallic organic framework (CoMnBDC) material with morphology of stacked nanosheets was synthesized using terephthalic acid as ligands to coordinate with Co2+ and Mn2+ cations under solvothermal conditions. As revealed by spectroscopic characterizations, the electron transfer from Mn to Co in the CoMnBDC resulted in the reduction of the Co average oxidation state and increase of the Mn average oxidation state. The CoMnBDC nanosheets were used as catalyst in catalytic oxidation of ethylbenzene, in which the redox effect promotes the effective electron transfer, the activation of O2 and benzyl C-H bond. The 96.2% conversion of ethylbenzene and 98.0% selectivity towards acetophenone could be obtained with oxygen as sole oxidant and solvent-free condition. The excellent catalytic performance is related to the structure of CoMnBDC and is also the best when compared with reported results. Various types of aromatic hydrocarbons containing benzyl C-H bonds can be effectively oxidized by CoMnBDC to produce corresponding ketone products. The density functional theory (DFT) calculation revealed that the redox effect leads to the relative enrichment of electrons on Co in CoMnBDC, which is conducive to the activation of O2; Mn with higher oxidation state is beneficial for the adsorption of ethylbenzene and activation of C-H bonds. The CoMnBDC has a lower energy barrier for transition state, making it easier for the ethylbenzene oxidation to produce acetophenone. [ABSTRACT FROM AUTHOR]

Pollution from persistent organic chlorinated pollutants (POCPs) in water environments is attributable to historical reasons and the lack of effective discharge regulations. Electrochemical degradation of POCPs, as a key study for POCP degradation, involves the use of electrons as reducing or oxidizing agents. The occurrence of this degradation depends on the environmental characteristics of the POCPs, the electrochemical materials used, and the technology and mechanisms involved. Furthermore, regarding the development of new materials and technologies, such as micro-, nano-, and atomic-sized materials, the degradation of POCPs achieves higher degradation efficiency and maximizes current utilization efficiency. In this review article, we first summarize the current status and future opportunities of the electrochemical degradation of POCPs. Environmental characteristics of POCPs facilitate a comparison of POCP degradation, and a comparison of electrochemical materials and their methods is made. Subsequently, we discuss technologies for the electrochemical degradation of POCPs from three aspects: oxidation, reduction, and a combination of oxidation and reduction. Moreover, the mechanisms were generalized in terms of molecular structure, electrode materials, and solution environment. In addition to maximizing the intrinsic enhancement factors of degradation, strategies to improve environmental accessibilities are equally important. This review article aims to effectively guide the advancement of POCP degradation and the remediation of environmental water pollution. [ABSTRACT FROM AUTHOR]

In this work, a series of high-entropy oxides (HEOs) was successfully prepared by the calcination of identical metal–organic framework (MOF) precursors. Thermal treatment above 400 °C led to the complete transformation of MOFs into HEOs. The performance of the obtained HEO catalysts in the removal of volatile organic compounds (VOCs) was studied with the catalytic oxidation of toluene as the probe reaction. The optimized Ce-HEO-400 catalyst showed impressive activity and stability over toluene catalytic oxidation, which resulted from the vast quantity of surface oxygen vacancies and the relatively variable metal valence. The T50 and T90 values of Ce-HEO-400 were 180 °C and 255 °C, respectively. Moreover, it also showed excellent stability for 120 h with a 98.5% toluene conversion rate at 260 °C. Combined with the characterizations of XRD, SEM, TEM, BET, H2-TPR, and XPS, it was found that the high dispersion of the active high-entropy structure and the synergistic effects of different metals are the key factors for improving the catalytic performance of the Ce-HEO-400 catalyst. This work not only presents a facile method for synthesizing HEO materials at low temperatures but also provides valuable technical support for the application of HEO catalysts in VOC removal. The findings of this study open up new possibilities for the development of efficient catalysts for the removal of VOCs. [ABSTRACT FROM AUTHOR]

The efficient separation of photocarriers and facile generation of superoxide radicals are crucial for enhancing the performance of photocatalysts in the selectively photo‐oxidizing 5‐hydroxymethylfurfural (HMF) into 2,5‐diformylfuran (DFF). Herein, a ZnIn2S4/CeO2 composite with S‐scheme heterojunction and sulfur vacancies (SV) is successfully developed through a one‐step hydrothermal method. The optimal catalyst (SV‐ZnIn2S4/CeO2) exhibits excellent catalytic activity with 100% conversion of HMF and 96.1% selectivity of DFF in 80 min under ambient conditions, the production rate of DFF is up to 952.6 µmol g−1 h−1. Intriguingly, the performance remains significant even when the concentration of HMF is increased from 8 to 100 mм. Experimental and theoretical investigations discover that the synergistic effect of S‐scheme heterojunction and sulfur vacancies contribute to the separation of photocarriers and the activation of oxygen, which facilitate the generation of superoxide radicals, thus boosting the catalytic oxidation reactions. [ABSTRACT FROM AUTHOR]

This work reported gold nanoparticles (AuNPs)-based colorimetric immunoassay with the Cu-based metal–organic framework (MOF) to load pyrroloquinoline quinone (PQQ) for the catalytic oxidation of cysteine. In this method, both Cu2+ and PQQ in the MOF could promote the oxidation of inducer cysteine by redox cycling, thus limiting the cysteine-induced aggregation of AuNPs and achieving dual signal amplification. Specifically, the recombinant carcinoembryonic antigen (CEA) targets were anchored on the MOF through the metal coordination interactions between the hexahistidine (His6) tag in CEA and the unsaturated Cu2+ sites in MOF. The CEA/PQQ-loaded MOF could be captured by the antibody-coated ELISA plate to catalyze the oxidation of cysteine. However, once the target CEA in the samples bound to the antibody immobilized on the plate surface, the attachment of CEA/PQQ-loaded MOF would be limited. Cysteine remaining in the solution would trigger the aggregation of AuNPs and cause a color change from red to blue. The target concentration was positively related to the aggregation and color change of AuNPs. The signal-on competitive plasmonic immunoassay exhibited a low detection limit with a linear range of 0.01–1 ng/mL. Note that most of the proteins in commercial ELISA kits are recombinant with a His6 tag in the N- or C-terminal, so the work could provide a sensitive plasmonic platform for the detection of biomarkers. [ABSTRACT FROM AUTHOR]

Hierarchically structured materials are considered to be one of the important options to enhance the mass transportation efficiency in microporous zeolites. Herein, we reported a highly efficient steam-assisted crystallization strategy for the synthesis of a hierarchical TS-1 zeolite with a tunable macropore size. The amorphous SiO2–TiO2 precursor dissolved gradually and acted as both a nutrient supplier and macropore template in situ. The framework Ti content of the synthesized TS-1 zeolites could be tuned over a wide range (Ti wt% = 0.70–1.39) by varying the Ti content of the SiO2–TiO2 precursor. Moreover, the pore size of the macropores could be modulated according to the particle size of the precursor based on the investigation of the formation mechanism of the macropores in the hierarchical TS-1 zeolite. The hierarchical TS-1 zeolite exhibited better catalytic activity in the epoxidation reaction of 1-hexene and hydroxylation of phenol compared to the typical microporous zeolites. The improved performance of the hierarchical TS-1 zeolite was probably caused by the improved diffusion performance of the hierarchical structure. [ABSTRACT FROM AUTHOR]

Cerium dioxide (CeO 2) supported palladium (Pd) catalysts have found widespread application in CO oxidation reaction owing to their exceptional catalytic performance. The morphology of the CeO 2 support dictates the exposed crystal plane, exerting a profound influence on surface structure and redox properties. This is crucial as the atomic arrangement at the surface directly impacts catalytic activity. In this study, a range of CeO 2 supports with diverse morphologies (e.g. nano-octahedra, nano-cubes, nano-particles, nano-spheres, and nano-rods) were successfully synthesized through hydrothermal methods and subsequently supported with Pd for CO oxidation. The spherical 1Pd/CeO 2 –S catalyst, revealing exposed (111) + (100) crystal planes, exhibited significantly higher CO catalytic oxidation activity compared to the catalysts with other morphological CeO 2 supports. The results indicated a positive correlation between the content of Pd x Ce 1-x O 2-y species and catalytic activity. Notably, this species was most abundantly formed in the spherical 1Pd/CeO 2 –S catalyst with exposed (111) + (100) crystal planes. The presence of this active species facilitated the formation of surface defects, increased oxygen vacancy concentration, and enhanced metal-support interaction, consequently greatly improving the CO low-temperature catalytic oxidation activity. Consequently, the oxidation state of Pd in the Pd/CeO 2 catalyst could be effectively regulated by controlling the exposure of (111) + (100) crystalline surfaces of the CeO 2 support, further optimizing the catalytic performance of the Pd/CeO 2 catalytic system. [ABSTRACT FROM AUTHOR]

Two Co‐based supramolecular isomers were synthesized from a fluorinated carboxylic acid ligand under hydrothermal conditions at varying temperatures. Both exhibited similar one‐dimensional chain structures while different bending connections of the aromatic rings led to different supramolecular structures, namely CoCP‐1 and CoCP‐2, respectively. The structural differences of two isomers resulted in discrepant performance with regards to luminescence sensing and catalysis. CoCP‐1 demonstrated more significant luminescence quenching activity toward biomarkers 2,6‐pyridinedicarboxylic acid (DPA) and homovanillic acid (HVA), which could be distinguished in the presence of Eu3+. The limit of detection (LOD) was found to be as low as 3.4 and 1.3 μM, respectively. The recovery rate of for HVA and DPA was within the range of 98.5–110.3 % and 84.6–99.3 % in simulated urine and serum, respectively, indicating potential reliability in monitoring these two analytes in real samples. Notably, CoCP‐2 exhibited catalytic activity for the oxidation of thioethers to sulfoxides. Our finding here suggests that the coordination conformation of the ligands within supramolecular isomers plays a pivotal role in determining the structure and luminescence sensing/catalysis performance. [ABSTRACT FROM AUTHOR]

NiMn oxides with different ratios (NixMnyOz) as well as spinel‐type NiMn2O4 oxides were synthesized and utilized in the catalytic oxidation of toluene. The results indicate that NiMn2Ox synthesized by the oxygen‐only roasting method exhibits superior catalytic activity due to the appropriate metal valence distribution. The catalytic activity is strongly related with the crystalline phase structures, NiMn2O4 spinel oxides catalyst shows the best low‐temperature performance with 90 % conversion (T90) at 230 °C. Characterization results reveal that the superb catalytic performance of NiMn2O4 spinel oxide is mainly profit by the larger surface area, more abundant surface fugacious oxygen, stronger toluene adsorption capacity than that of the other NixMnyOz catalysts, which in favor of the speedy conversion of benzoic acid, improving the toluene catalytic performance. This finding provides a novel design strategy of NiMn composite oxides for synthesis of high‐efficiency performance toluene catalysts. [ABSTRACT FROM AUTHOR]

Ammonia is a promising candidate in the quest for sustainable, clean energy. With its capacity to serve as an energy carrier, the oxidation of ammonia opens avenues for carbon‐neutral approaches to address worldwide growing energy needs. We report the catalytic chemical oxidation of ammonia by an Earth‐abundant transition metal complex, trans‐[LFeII(MeCN)2][PF6]2, where L is a macrocyclic ligand bearing four N‐heterocyclic carbene (NHC) donors. Using triarylaminium radical cations in MeCN, up to 182 turnovers of N2 per Fe were obtained from chemical catalysis with an extremely low loading of the Fe catalyst (0.043 mM, 0.004 mol % catalyst). This chemical catalysis was successfully transitioned to mediated electrocatalysis for the oxidation of ammonia. Molecular electrocatalysis by the Fe catalyst and the mediator (p‐MeOC6H4)3N exhibited a catalytic half‐wave potential (Ecat/2) of 0.18 V vs [Cp2Fe]+/0 in MeCN, and achieved 9.3 turnovers of N2 at an applied potential of 0.20 V vs [Cp2Fe]+/0 at −20 °C in controlled‐potential electrolysis, with a Faradaic efficiency of 75 %. Based on computational results, the catalyst undergoes sequential oxidation and deprotonation steps to form [LFeIV(NH2)2]2+, and thereafter bimetallic coupling to form an N−N bond. [ABSTRACT FROM AUTHOR]

We report an in-depth study of the reductive activation of O2 by the nonheme [FeII(L 25)(MeCN)]2+ complex carried out by cyclic voltammetry. Experimental evidence is obtained for the slow coordination of dioxygen to the ferrous center yielding an FeII/O2 adduct with a strong FeII–O2 character rather than an FeIII–superoxo one. Electron injection in the FeII–O2 species occurs at a potential of ca. −700 mV vs. SCE, i.e. 200 mV above the O2 to O2˙− reduction, leading to the formation of a FeIII–peroxo intermediate and then FeIII–hydroperoxo upon protonation by residual water. The experimental CVs recorded at variable scan rate or variable FeII concentration are well simulated taking into account a detailed mechanism initiated by the competitive reduction of O2 and the FeII–O2 adduct. Analysis of the concentration of the reaction intermediates generated as a function of the applied potential indicates that the FeIII–peroxo intermediate significantly accumulates at a potential of −650 mV. Oxidative bromination of anisole is assayed under electrolytic conditions at this potential to yield bromoanisole products. The low faradaic yields observed reveal that deleterious reactions such as direct reduction of reaction intermediates likely occur. Based on the detailed mechanism elucidated, a number of improvements to achieve more efficient catalytic reactions can be proposed. [ABSTRACT FROM AUTHOR]

Breast cancer, the most common malignant tumor in the world, seriously threatens human life and health. Early diagnosis of breast cancer may help enhance the survival rate. In this work, a colorimetric and fluorescent dual-mode biosensor based on the CRISPR-Cas12a system was constructed to detect the breast cancer biomarker BRCA1. The intact G4 DNA, with the assistance of K+ and hemin, catalyses the oxidation of o-phenylenediamine (OPD) with the assistance of hydrogen peroxide (H2O2), generating the oxidation product 2,3-diaminophenazine (DAP), which has distinct absorption and fluorescence peaks. The presence of the target BRCA1 activates the trans-cleavage activity of CRISPR-Cas12a, leading to the cleavage of G4 DNA and inhibiting the catalytic oxidation of OPD. Target BRCA1 was quantitatively determined by measuring both the absorbance and fluorescence intensity of DAP. The detection limits were calculated to be 0.615 nM for the colorimetric method and 0.289 nM for the fluorescence method. The dual-mode biosensor showed good selectivity and reliability for BRCA1 and can resist interference from complex substrates, and it has great potential in biomedical detection. [ABSTRACT FROM AUTHOR]

Formaldehyde (HCHO), which is one of the common pollutants in indoor environment and industrial processes, can cause adverse effects on human health. The thermal catalytic oxidation technology is regarded as the most promising approach due to its easy handling and environmental friendliness. This article reviews the current status of the catalytic oxidation of HCHO over noble metal and transition metal oxide catalysts. The general feature and the reaction mechanism of the catalytic oxidation of HCHO are summarized first. Based on the discussion of the reaction mechanism, the influence of some factors (catalyst preparation process, catalyst support, promoter and morphology) on the activity of the catalyst have been addressed. The structure of the catalysts has been elucidated and correlated with the reaction mechanism as well as the catalytic performance. Finally, the perspectives for the catalytic oxidation of HCHO in future research are presented. Hopefully, this review can shed light on the design of more active catalysts for HCHO oxidation to realize their practical application. [ABSTRACT FROM AUTHOR]

A new method of reducing the amount of reagent and sample for determination of thrombomodulin (TM) was developed based on competitive immunoreaction using a portable glucometer (PGM). Two types of nanocomposites, TM protein-modified magnetic nanoparticles (MNPs-TM) and TM antibody-/glucose oxidase-modified gold nanoparticles (Ab-GNPs-GOx), were prepared. Their binding product, MNPs-TM-Ab-GNPs-GOx, in the microvolumetric solution was used to catalyze the oxidation of glucose, leading to a decline of the glucose content. The TM-involved competitive immunoreaction had a negative effect on the generation of MNPs-/GNPs-based nanocomposites and inhibited the catalytic oxidation of glucose. The glucose content difference in the microvolumetric solution, which was revealed by a PGM, was in proportion to the logarithm of the TM concentration from 25 ng mL−1 to 2.5 μg mL−1. The limit of detection was 5.7 ng mL−1. Microvolumetric solution and a PGM were used in the measurement, which overcame some deficiencies of classical methods in chemo/biosensing, for example, special instrument, complicated measurement procedure, and high cost. [ABSTRACT FROM AUTHOR]

Bimetallic synergism can effectively improve the catalytic activity of the catalyst. In this work, different catalysts were synthesized by loading Co and Ce onto copper foam (CF) by impregnation method and applied to the catalytic oxidation of toluene. Catalytic performance of the Co/Ce loaded catalysts was significantly better than the CF. Among these catalysts, Co1Ce2/CF catalyst had the best catalytic activity of toluene (T90 = 237 °C), the lowest apparent activation energy (Ea = 35.0 kJ/mol), excellent stability (40 h) and cycle stability (three cycle) at a toluene concentration of 1000 mg/m3 under WHSV = 15,000 mL/(g·h). The good catalytic activity of Co1Ce2/CF catalyst is mainly due to a higher proportion of lattice oxygen, Ce4+ and Co2+. Ce4+ and Co2+ can provide more oxygen vacancies for the catalyst. By H2-TPR and O2-TPD, it is found that Co1Ce2/CF catalyst's effective catalytic activity is probably attributed to its low reduction temperature, ample oxygen storage capacity and low oxygen desorption temperature. In addition, the degradation process of toluene on the catalyst was speculated. The physical and chemical properties of the catalysts were investigated by SEM, EDS, XRD, XPS, BET, H2-TPR and O2-TPD. This work provides an effective way for synthesizing Co-Ce bimetallic oxide supported catalysts with great potential in toluene treatment. [ABSTRACT FROM AUTHOR]

Particle size is critical in determining the catalytic behavior of noble metal catalysts. It is a significant interest for the rational design of clearly defined catalyst materials to research on noble metal nanoparticles. Herein, a facile prepared method for the Pt/TiO2 catalysts can not only potentially benefit the reuse of industrial catalysts, but also help to reduce the cost of VOC catalytic oxidation. In this work, the calcination of Pt/TiO2 catalyst under N2 atmosphere achieves the redispersion of large Pt particles into small ones (~ 1.4 nm). The Pt/TiO2-400 catalyst (calcinated at 400 °C) with smaller Pt particles and higher concentration of active sites has superior catalytic activity and stability of toluene oxidation, contributing to the strong metal-support interaction, the larger effective metal surface area, the excellent low-temperature reducibility, abundant amounts of Pt0 species and adsorbed oxygen species. This work provides a facile method for metal redispersion of the catalysts, maintaining high activity and excellent stability. [ABSTRACT FROM AUTHOR]

Bisphenols as an important industrial raw material has endocrine disruption, reproductive toxicity, and neurotoxicity. Laccase (Lac) has demonstrated excellent catalytic oxidation performance for phenolic compounds. Micro-nano bubbles (MNB) have been extensively used in wastewater treatment, and the high efficiency of MNB-assisted laccase (MNB-Lac) as a hybrid technique for removing bisphenols from water has been established. In this study, MNB-Lac system was used to degrade bisphenols including bisphenol A (BPA), bisphenol B (BPB), bisphenol C (BPC), bisphenol E (BPE), and bisphenol F (BPF). A comparative analysis was conducted to evaluate the degradation of individual and mixed bisphenols by MNB-Lac. The results indicated that the degradation effect on all individual bisphenols was superior. Notably, BPC consistently demonstrated higher selectivity in the mixed degradation process. In the mixed bisphenol degradation process, a distinct degradation sequence between BPE and BPF was observed. The affinity order of BPA and BPE was found to be inconsistent with their individual degradation order, and the degradation reaction was found to conform to second-order kinetics. By gas chromatography mass spectrometry detection, it was found that the degraded products of BPA, BPB, BPC, BPE, and BPF were ring and chain compounds, and the degradation pathways of the five substances were also maintenance ring structure and direct ring opening. The possible transformation relationship of mixed bisphenols during degradation by MNB-Lac was proposed. Moreover, the industrial application of MNB-Lac was evaluated by increasing the wastewater volume of BPA. [ABSTRACT FROM AUTHOR]

[Display omitted] Promoting lattice oxygen mobility of Co-based catalysts is crucial to making progress in catalytic oxidation technology. The addition of manganese, a transition metal with similar ionic radius to cobalt and variable valence, was supposed to enhance the mobility of lattice oxygen species of Co-based oxide. A range of hollow CoMn a O x sub-nanosphere catalysts with different Mn/Co ratios was synthesized via a template-sacrificed method, and the effects of different Mn/Co ratios on the structural properties of the catalysts and their catalytic performance for benzene series volatile organic compounds (VOCs) oxidation were investigated. Hollow CoMn 2 O x sub-nanosphere exhibited good catalytic activity for oxidation of toluene (T 90 = 265 °C) and o-xylene (T 90 = 297 °C), as well as excellent recycling ability and water resistance. By adjusting the Mn/Co ratio, metal ions enter into the different tetrahedral or octahedral active sites. Compared with Co 3 O 4 , the desorption temperature of surface lattice oxygen on CoMn 2 O x decreased by 110 °C. These results demonstrate that the addition of manganese can encourage the electron transfer on CoMn a O x , indicating that the introduction of the appropriate amount of manganese accelerates the activation of gas O 2 and mobility of surface lattice oxygen species, thereby expediting the oxidation of benzene series VOCs. [ABSTRACT FROM AUTHOR]

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In the preparation of a series of Ce0.8Zr0.2Oy catalysts catalyzing the removal of formaldehyde, BET, H2-TPR, IR, SEM, XPS, and XRD were used to characterize the catalyst, and the influence of humidity on the catalyst activity was studied by adjusting the humidity during the process. The experimental results showed that the formaldehyde removal rate increased with the increase of humidity. When the humidity was higher than 50%, the formaldehyde removal rate decreased by 3% over that when the humidity was 50%.The characterization results showed that humidity facilitated the activation of oxygen and the formation of hydroxyl groups, which both promoted the formation and oxidative decomposition of intermediates and prevented the deposition of intermediates that clogged the pores, allowing more formaldehyde to be adsorbed and oxidized, which increased the activity of the catalyst. This provides new mechanistic evidence for the oxidation of formaldehyde and helps in the development of relatively low-cost materials for formaldehyde purification. [ABSTRACT FROM AUTHOR]

Diesel engines are widely used because of their high power, and diesel particulate filters can effectively control the emission of particulate matter from diesel engines, in which catalysts have a non-negligible role. This paper reviews the research progress of catalyst solutions for catalytic carbon soot combustion in diesel particulate filters in recent years. Firstly, the paper describes the various factors affecting the catalyst activity and the methods for evaluating the catalytic activity. Secondly, it summarizes the catalytic and non-catalytic mechanisms of soot combustion. After that, the paper even focuses on different catalyst types and structures, emphasizing the formulation of catalysts with unique structures. Finally, a brief review of composite regeneration technologies for particulate filters is presented. This paper highlights previous catalyst formulations with good catalytic performance and identifies areas of subsequent research that may provide helpful guidance for future research and commercialization. [ABSTRACT FROM AUTHOR]

Owing to the structural stability, modifiable acidity, and abundant pores/channels, zeolite‐based materials can act as catalysts or supports for effective conversion of volatile organic compounds (VOCs). In this review, a series of VOC oxidation processes catalyzed by zeolite‐based materials will be introduced, which include thermal oxidation, photocatalytic degradation, plasma‐driven removal, catalytic ozonation, microwave‐assisted degradation, and hybrid systems, where the specific roles, modification strategies, and structure–performance relationships of zeolites are discussed in depth. The following topics will also be covered, including the catalytic mechanisms of VOC oxidation, types of zeolite‐based materials in VOC catalytic oxidation, operation parameters in the processes, and reactor designs for efficiency optimization and cost control. [ABSTRACT FROM AUTHOR]

L‐Ascorbic acid, also known as vitamin C, is a very important antioxidant ingredient situated many usage areas in different industries. 2‐keto‐L‐gulonic acid (2‐KLG) is the main precursor component of L‐ascorbic acid production and it can be produced from L‐sorbose via microbial fermentation or chemical (catalytic) oxidation. While some special strains are used in microbial fermentation, it is benefitted from some catalysts in chemical oxidation. Herein, it was aimed to determine the optimum reaction temperature, pH, and time conditions to produce maximum 2‐KLG compound with the catalytic oxidation of L‐sorbose in the presence of Pt/Al2O3 catalyst with response surface methodology approach. For this aim, the reaction temperature, pH, and time used as variable factors. The limit values of variable factors were applied as 40–60 °C for the temperature, 7.00–9.00 for the pH value, and 3–9 h for the time. The analyses results demonstrated that the increasing temperature and time negatively effected the conversion of L‐sorbose into the 2‐KLG. The optimum conditions of variable factors were determined as 41.30 °C for the temperature, 8.23 for the pH, and 3.25 h for the reaction time by the central composite design. Under these optimum conditions, L‐sorbose was converted into 2‐KLG with an average yield of 43.70 %. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) are typical pollutants with hazards for humans and the environment, which can be efficiently mitigated by catalytic combustion. Fe2O3‐based catalysts are a promising choice due to their low cost and strong redox ability. Several attempts have been made to promote the catalytic performance for Fe2O3‐based catalysts at low temperatures. This review summarizes the research progress on Fe2O3‐based catalysts for the oxidation of toluene, one of the most common and harmful VOC. Firstly, the structural properties and catalytic performances for Fe2O3‐based catalysts have been summarized, and the reaction mechanisms for toluene oxidation on the surface of Fe2O3‐based catalysts were detailed to comprehend the role of oxygen vacancies. Then, the modification for single Fe2O3 catalysts, including synthesis parameters, structure and morphology control, is introduced to reveal the correlation between physicochemical properties of catalysts and their activity for toluene oxidation. In addition, composite Fe2O3 catalysts, which can promote catalytic performance significantly by the synergetic effect between different components, were presented in detail. Moreover, waste‐derived Fe2O3 catalysts with sustainable merit as converting waste into worth have been discussed. Finally, the advanced machine learning tools, which are helpful in accelerating catalyst design, configuration optimization and reactivity prediction, have been introduced as an emerging research opportunity for the future. [ABSTRACT FROM AUTHOR]

By the reaction of the binuclear cobalt-containing polyoxovanadate [Co2(H2O)2V10O30]6− with methanol, a tridecanuclear cobalt containing polyoxovanadate, [Co13(OH)6(OCH3)6V24O72]10− (Co13), was synthesized. Single crystals suitable for X-ray crystallographic analysis were obtained as trimethylphenylammonium salts. The tridecanuclear cobalt core exhibited a planar disk structure and 24 vertex-sharing VO4 units surrounded the edge of the disk. This is the largest VO4-based polyoxovanadate as far as we know. Compound Co13 was stable in the solution state. Electrochemical analysis showed the possibility of Co13 to act as an oxidation catalyst for alcohols. Compound Co13 acted as a catalyst for oxidation of several alcohols. After the reaction, the Co13 catalyst was retrieved by the addition of an excess amount of ethyl acetate and filtration. The structure of the catalyst was maintained and reused. The oxidation of not only aromatic but also aliphatic alcohols proceeded with Co13. Compound Co13 showed catalytic performance for the oxidation of secondary alcohols even in the presence of alkenic and primary alcoholic functions. [ABSTRACT FROM AUTHOR]