Siloxane-modified MnOx catalyst for oxidation of coal-related o-xylene in presence of water vapor

Chemical Design of Magnetic Nanomaterials for Imaging and Ferroptosis-Based Cancer Therapy

Ferroptosis, an iron-dependent form of regulatory cell death, has garnered significant interest as a therapeutic target in cancer treatment due to its distinct characteristics, including lipid peroxide generation and redox imbalance. However, its clinical application in oncology is currently limited by issues such as suboptimal efficacy and potential off-target effects. The advent of nanotechnology has provided a new way for overcoming these challenges through the development of activatable magnetic nanoparticles (MNPs). These innovative MNPs are designed to improve the specificity and efficacy of ferroptosis induction. This Review delves into the chemical and biological principles guiding the design of MNPs for ferroptosis-based cancer therapies and imaging-guided therapies. It discusses the regulatory mechanisms and biological attributes of ferroptosis, the chemical composition of MNPs, their mechanism of action as ferroptosis inducers, and their integration with advanced imaging techniques for therapeutic monitoring. Additionally, we examine the convergence of ferroptosis with other therapeutic strategies, including chemodynamic therapy, photothermal therapy, photodynamic therapy, sonodynamic therapy, and immunotherapy, within the context of nanomedicine strategies utilizing MNPs. This Review highlights the potential of these multifunctional MNPs to surpass the limitations of conventional treatments, envisioning a future of drug-resistance-free, precision diagnostics and ferroptosis-based therapies for treating recalcitrant cancers.

Investigation into enhanced performance of toluene and Hg0 stimulative abatement over Cr-Mn oxides co-modified columnar activated coke

In this study, a string of Cr-Mn co-modified activated coke catalysts (XCryMn1-y/AC) were prepared to investigate toluene and Hg0 removal performance. Multifarious characterizations including XRD, TEM, SEM, in situ DRIFTS, BET, XPS and H2-TPR showed that 4%Cr0.5Mn0.5/AC had excellent physicochemical properties and exhibited the best toluene and Hg0 removal efficiency at 200℃. By varying the experimental gas components and conditions, it was found that too large weight hourly space velocity would reduce the removal efficiency of toluene and Hg0. Although O2 promoted the abatement of toluene and Hg0, the inhibitory role of H2O and SO2 offset the promoting effect of O2 to some extent. Toluene significantly inhibited Hg0 removal, resulting from that toluene was present at concentrations orders of magnitude greater than mercury's or the catalyst was more prone to adsorb toluene, while Hg0 almost exerted non-existent influence on toluene elimination. The mechanistic analysis showed that the forms of toluene and Hg0 removal included both adsorption and oxidation, where the high-valent metal cations and oxygen vacancy clusters promoted the redox cycle of Cr3+ + Mn3+/Mn4+ ↔ Cr6+ + Mn2+, which facilitated the conversion and replenishment of reactive oxygen species in the oxidation process, and even the CrMn1.5O4 spinel structure could provide a larger catalytic interface, thus enhancing the adsorption/oxidation of toluene and Hg0. Therefore, its excellent physicochemical properties make it a cost-effective potential industrial catalyst with outstanding synergistic toluene and Hg0 removal performance and preeminent resistance to H2O and SO2.

Recent Advances of the Effect of H2O on VOC Oxidation over Catalysts: Influencing Factors, Inhibition/Promotion Mechanisms, and Water Resistance Strategies

Water vapor is a significant component in real volatile organic compounds (VOCs) exhaust gas and has a considerable impact on the catalytic performance of catalysts for VOC oxidation. Important progress has been made in the reaction mechanisms of H2O and water resistance strategies for VOC oxidation in recent years. Despite advancements in catalytic technology, most catalysts still exhibit low activity under humid conditions, presenting a challenge in reducing the adverse effects of H2O on VOC oxidation. To develop water-resistant catalysts, understanding the mechanistic role of H2O and implementing effective water-resistance strategies with influencing factors are imperative. This Perspective systematically summarizes related research on the impact of H2O on VOC oxidation, drawing from over 390 papers published between 2013 and 2024. Five main influencing factors are proposed to clarify their effects on the role of H2O. Five inhibition/promotion mechanisms of H2O are introduced, elucidating their role in the catalytic oxidation of various VOCs. Additionally, different kinds of water resistance strategies are discussed, including the fabrication of hydrophobic materials, the design of specific structures and morphologies, and the introduction of additional elements for catalyst modification. Finally, scientific challenges and opportunities for enhancing the design of efficient and water-resistant catalysts for practical applications in VOC purification are highlighted.

Synergistic removal of Hg0, HCl, and SO2 from flue gas in municipal solid waste incineration by mechanically modified fly ash

The emissions of flue gas components (such as Hg0, SO2, HCl) and the generation of hazardous waste fly ash from municipal waste incineration pose a significant threat to environmental integrity. In this study, a mechanochemical method combined with a modifier is innovatively proposed for the modification of fly ash to remove Hg0. In the fixed bed adsorption experiment, the removal efficiency of up to 60 percent can be achieved by ball milling (700rap,30min) alone. The modification of fly ash by mechanical force coupling with pyrite can achieve Hg0 removal efficiency is increased to more than 90 percent. By taking advantage of the excellent adsorption capacity of modified fly ash for acidic gases, the enhancement of S and Cl∗ active sites on the surface of modified fly ash strengthened the removal efficiency of modified fly ash for Hg0. DFT simulations evidenced that the defective S sites caused by the ball milling process could enhance the adsorption capacity of pyrite for Hg0. The fly ash was modified with mechanically coupled pyrite and alkalis and was able to have good adsorption capacity for acidic gases, the highest removal effect reached 93.1% and 96.7% for SO2 and HCl, respectively. The adsorbed acid gases increased the S and Cl∗ active sites, which led to the removal of Hg0 from the modified fly ash to more than 94.4%, achieving the synergistic removal of acid gases and Hg0. This method can realize the integrated technical route of "Fly ash collection - Online modification - Timely injection". A novel investigation was conducted on the elimination of flue gas contaminants and the reutilization of perilous fly ash.

Effect of inserting Cr in promoting the deep oxidation of dichloromethane over Co/WNb catalysts at low temperatures

Enhancing catalytic activity while inhibiting the generation of chlorine byproducts is essential in the catalytic oxidation process of chlorinated volatile organic compounds (CVOCs). In this study, Cr-modified Co/WNb catalysts were synthesized and utilized for the degradation of dichloromethane (DCM). It was found that the moderate introduction of Cr exposed more Cr6+ on the catalyst surface due to the interaction between cobalt and chromium oxides, which promoted the generation of more chemisorbed oxygen on the surface, thus improving the redox properties and enhancing the activity of the catalysts. Additionally, the introduction of Cr increased the B acid sites of the catalysts, promoting the breaking of C-Cl bonds and the removal of dissociated Cl- Meanwhile, the improved redox properties also allowed further oxidation of the dissociated activated intermediate products and inhibited the generation of chlorine byproducts. The catalyst activity was optimal when the Cr to Co molar ratio was 4, which the T90 of DCM was 256 °C and the monochloromethane selectivity was only 1.7 %. Moreover, Co4Cr/WNb showed excellent chlorine and water resistance, making it an ideal candidate for CVOC degradation.

Boosting catalytic stability for VOCs removal by constructing PtCu alloy structure with superior oxygen activation behavior

The elimination of volatile organic compounds (VOCs) emitted from the process of industry production is of great significance to improve the atmospheric environment. Herein the catalytic oxidation of the toluene and iso-hexane mixture, as the typical components from furniture paint industry, and the enhancement in the catalytic stability for toluene oxidation were investigated in detail. The formation rate of active oxygen species was very important for the development of the catalyst with high catalytic stability. Compared with the Pt/M catalyst, the Pt-Cu/M catalyst owned stronger ability of VOCs adsorption and gaseous oxygen activation by introducing additional sites for activating O₂. The Langmuir-Hinshelwood (adsorbed oxygen) and Mars-van Krevelen (lattice oxygen) mechanism existed in toluene oxidation over the present Pt/M and Pt-Cu/M catalysts, respectively. The change in the involved active oxygen species during toluene oxidation was resulted from the Pt-Cu alloy structure. In addition to the adsorption of O₂, a part of active lattice oxygen species can also be replenished by the migration of bulk lattice oxygen over Pt-Cu/M. With a rise in the reaction temperature, weakly adsorbed iso-hexane could be timely reacted with the more active lattice oxygen species to keep the catalytic stability over the Pt/M and Pt-Cu/M catalysts. Generally, we not only prepared a promising material for the catalytic removal of VOCs from the furniture paint industry, but also provided a new strategy for the generation of active oxygen species, making the catalyst exhibit high catalytic oxidation stability.

Recent progress of catalytic methane combustion over transition metal oxide catalysts

Methane (CH4) is one of the cleanest fossil fuel resources and is playing an increasingly indispensable role in our way to carbon neutrality, by providing less carbon-intensive heat and electricity worldwide. On the other hand, the atmospheric concentration of CH4 has raced past 1,900 ppb in 2021, almost triple its pre-industrial levels. As a greenhouse gas at least 86 times as potent as carbon dioxide (CO2) over 20 years, CH4 is becoming a major threat to the global goal of deviating Earth temperature from the +2°C scenario. Consequently, all CH4-powered facilities must be strictly coupled with remediation plans for unburned CH4 in the exhaust to avoid further exacerbating the environmental stress, among which catalytic CH4 combustion (CMC) is one of the most effective strategies to solve this issue. Most current CMC catalysts are noble-metal-based owing to their outstanding C–H bond activation capability, while their high cost and poor thermal stability have driven the search for alternative options, among which transition metal oxide (TMO) catalysts have attracted extensive attention due to their Earth abundance, high thermal stability, variable oxidation states, rich acidic and basic sites, etc. To date, many TMO catalysts have shown comparable catalytic performance with that of noble metals, while their fundamental reaction mechanisms are explored to a much less extent and remain to be controversial, which hinders the further optimization of the TMO catalytic systems. Therefore, in this review, we provide a systematic compilation of the recent research advances in TMO-based CMC reactions, together with their detailed reaction mechanisms. We start with introducing the scientific fundamentals of the CMC reaction itself as well as the unique and desirable features of TMOs applied in CMC, followed by a detailed introduction of four different kinetic reaction models proposed for the reactions. Next, we categorize the TMOs of interests into single and hybrid systems, summarizing their specific morphology characterization, catalytic performance, kinetic properties, with special emphasis on the reaction mechanisms and interfacial properties. Finally, we conclude the review with a summary and outlook on the TMOs for practical CMC applications. In addition, we also further prospect the enormous potentials of TMOs in producing value-added chemicals beyond combustion, such as direct partial oxidation to methanol.