The Nature of Interfacial Catalysis over Pt/NiAl2O4 for Hydrogen Production from Methanol Reforming Reaction.

Reforming of methanol is one of the most favorable chemical processes for on-board H2 production, which alleviates the limitation of H2 storage and transportation. The most important catalytic systems for methanol reacting with water are interfacial catalysts including metal/metal oxide and metal/carbide. Nevertheless, the assessment on the reaction mechanism and active sites of these interfacial catalysts are still controversial. In this work, by spectroscopic, kinetic, and isotopic investigations, we established a compact cascade reaction model (ca. the Langmuir-Hinshelwood model) to describe the methanol and water activation over Pt/NiAl2O4. We show here that reforming of methanol experiences methanol dehydrogenation followed by water-gas shift reaction (WGS), in which two separated kinetically relevant steps have been identified, that is, C-H bond rupture within methoxyl adsorbed on interface sites and O-H bond rupture within OlH (Ol: oxygen-filled surface vacancy), respectively. In addition, these two reactions were primarily determined by the most abundant surface intermediates, which were methoxyl and CO species adsorbed on NiAl2O4 and Pt, respectively. More importantly, the excellent reaction performance benefits from the following bidirectional spillover of methoxyl and CO species since the interface and the vacancies on the support were considered as the real active component in methanol dehydrogenation and the WGS reaction, respectively. These findings provide deep insight into the reaction process as well as the active component during catalysis, which may guide the design of new catalytic systems.

Electrochemical Synthesis of Copper Mesh-Supported Thermo-Catalysts.

Metallic substrates, widely studied in the context of monolithic catalysts, offer inherent advantages in heterogeneous catalysis due to their exceptional thermal conductivity and mechanical properties. However, synthesizing stable monolithic catalysts with metallic substrates in a well-controlled manner remains a significant challenge. Here, this work introduces a simple, cost-efficient method to fabricate robust Cu mesh-supported thermo-catalysts using a modified cycling chronopotentiometry approach, where the Cu mesh serves as a donor of Cu ions. In this method, the Cu mesh surface generates two distinct layers of CuO and Cu2 O. In this context, CuO acts as the active phase, accounting for the high CO oxidation activity of Cu mesh catalysts with T90 ≈ 120 °C. Additionally, these catalysts exhibit considerable potential in electrocatalysis, showcasing significant research and application value.

Unveiling the intrinsic role of water in the catalytic cycle of formaldehyde oxidation: a comprehensive study integrating density functional theory and microkinetic analysis.

Previous research is predominantly in consensus on the reaction mechanism between formaldehyde (HCHO) and oxygen (O2) over catalysts. However, water vapor (H2O) always remains present during the reaction, and the intrinsic role of H2O in the oxidation of HCHO still needs to be fully understood. In this study, a single-atom catalyst, Al-doped C2N substrate, Al1/C2N, can be adopted as an example to investigate the relationship and interaction among O2, H2O, and HCHO. Density functional theory (DFT) calculations and microkinetic simulations were carried out to interpret the enhancement mechanism of H2O on HCHO oxidation over Al1/C2N. The outcome demonstrates that H2O directly breaks down a surface hydroxyl group on Al1/C2N, considerably lowering the energy required to form crucial intermediates, thus promoting oxidation. Without H2O, Al1/C2N cannot effectively oxidize HCHO at ambient temperature. During oxidation, H2O takes the major catalytic responsibility, delaying the entrance of O2 into the reaction, which is not only the product but also the crucial reactant to initiate catalysis, thereby sustaining the catalytic cycle. Moreover, this study predicts the catalytic behavior at various temperatures and presents feasible recommendations for regulating the reaction rates. The oxidation mechanism of HCHO is explained at the molecular level in this study, emphasizing the intrinsic role of water on Al1/C2N, which fills in the relevant studies for HCHO oxidation on two-dimensional carbon materials.

Alcohol-Induced Strong Metal-Support Interactions in a Supported Copper/ZnO Catalyst.

Tuning the strong metal-support interaction (SMSI) in metal catalysts is a promising strategy to improve their catalytic performance. In this article, we systematically investigated the influences of different alcohol/water mixtures on the evolution of the interfacial structure of Cu/ZnO catalysts in the reduction stage. A series of in situ characterization and theoretical simulation studies were performed to elucidate the various mechanisms of alcohol induced SMSI. It was found that when methanol/water is added to H2 during the reduction pretreatment, more oxygen vacancies are formed on the ZnO support, which facilitates the dissociation of H2 O and the hydroxylation of ZnO species. Such promotion eventually favors the SMSI between Cu and ZnO and increases the catalytic activity for the methanol steam reforming reaction. In contrast, the addition of ethanol/water and 1-propanol/water during reduction leads to a physical blockage of the catalyst by alcohol molecules, poisoning the active Cu sites and limiting the migration of ZnO species.

Removal of Gaseous Volatile Organic Compounds by a Multiwalled Carbon Nanotubes/Peroxymonosulfate Wet Scrubber.

In this study, a wet scrubber coupled with a persulfate-based advanced oxidation process [carbocatalysts/peroxymonosulfate (PMS)] was demonstrated to efficiently remove gaseous volatile organic compounds (VOCs). The removal efficiency of a representative VOC, styrene, was stable at above 98%, and an average mineralization rate was achieved at 76% during 2 h. The removal efficiency of the carbocatalysts/PMS wet scrubber for styrene was much higher than that of pure water, carbocatalysts/water, or PMS/water systems. Quenching experiments, electron spin resonance spectroscopy, in-situ Raman spectroscopy and density functional theory (DFT) calculations indicated that singlet oxygen (1O2) and oxidative complexes are the main reactive oxygen species and that both contributed to styrene removal. In particular, carbonyl groups (C═O) in the carbocatalyst were found to be the active sites for activating PMS during styrene oxidation. The role of 1O2 was discovered to be benzene ring breaking and a possible non-radical oxidation pathway of styrene was proposed based on time-of-flight mass spectroscopy which was further verified by DFT calculations. In particular, the electron transfer process of multi world carbon nanotubes-PMS* in styrene oxidation was further studied in-depth by experiments and DFT calculations. The unstable vinyl on styrene was simultaneously degraded by the oxidative complexes and 1O2 into benzene, and finally oxidized by 1O2 into H2O and CO2. This study provides an effective method for VOC removal and clearly illustrates the complete degradation mechanism of styrene in a nonradical PMS-based process by a wet scrubber.

Novel insights into photoaging mechanisms and environmental persistence risks of polylactic acid (PLA) microplastics: Direct and indirect photolysis.

Polylactic acid (PLA), as a biodegradable plastic, exhibits high sensitivity to ultraviolet (UV) radiation, yet the mechanisms and environmental risks of its photoaging remain unclear. This study uses quantum chemical calculations (DFT and TD-DFT) and kinetic simulations to explore the direct and indirect photoaging of PLA. Direct photoaging indicates that the highest oscillator intensity absorption peaks occurred at 172 and 246 nm, corresponding to the 13th singlet (S13) and 48th triplet (T48) states, thereby initiating the Norrish I and Norrish II mechanisms. The innovative "electron-hole" technology effectively clarifies the variations in photoaging mechanisms under different wavelengths. Indirect photoaging involves multiple reactive oxygen species (ROS) like •OH, 1O2, •O2-, and •HO2. The study confirms the anhydride production hypothesis and proposes two novel •OH-induced mechanisms: carbonyl carbon addition and branched methyl hydrogen dehydrogenation. Both mechanisms are thermodynamically advantageous, but their products pose potential environmental risks. ROS species and concentrations impact both PLA's photoaging mechanisms and environmental persistence. Low •OH concentration in northeast China, especially in winter, suggests a significant photoaging risk. This study offers pioneering insights into photoaging mechanisms and emphasizes the pivotal role of ROS, offering recommendations for managing PLA environmental impacts and fates in China.

Investigating the pharmacological mechanism of Zhengyuan jiaonang for treating colorectal cancer via network pharmacology analysis and experimental verification.

ETHNOPHARMACOLOGICAL RELEVANCE: Zhengyuan jiaonang (ZYJN) is a traditional Chinese patent medicine (CPM) used in China for adjuvant cancer therapy, which has been proved to have anti-fatigue effects. AIM OF STUDY: The study aims to investigate the antitumor effects of ZYJN and its underlying mechanisms using subcutaneous transplant CT26 model. MATERIALS AND METHODS: Fingerprint analysis of ZYJN was performed using high performance liquid chromatography. The potential targets of ZYJN were predicted using bioinformatic analysis, which were further validated by Western Blot assay. Subcutaneous transplant CT26 model was used to evaluate the antitumor effects of ZYJN. The effects of ZYJN on the tumor immune microenvironment were investigated by flow cytometry. Transparent imaging was used to investigate the effects of ZYJN on fibrosis and angiogenesis. RESULTS: ZYJN could inhibit colorectal cancer growth when administered alone or in combination with 5-FU. The combination of ZYJN and 5-FU could significantly increase the serum level of albumin (ALB) and decrease the serum level of aspartate aminotransferase (AST). In addition, the combination of ZYJN at 0.75 g/kg and 5-FU significantly decreased the serum level of vascular endothelial growth factors (VEGF) and inhibited the angiogenesis of CT26 cancer. The combination of ZYJN at 1.50 g/kg and 5-FU could promote the fibrosis process of CT26 cancer. Additionally, combination of ZYJN and 5-FU could significantly increase the percentage of tumor-infiltrating T cells and CD4+ T cells in the late stage of CT26 model, while ZYJN at 1.50 g/kg increased the percentage of NK cells as well as CD8+ T cells in the early stage of CT26 model. Western Blot analysis revealed that administration of ZYJN at 0.75 g/kg reduced the expression of PI3K-p110α, CDK1, CCNB1 and MMP-9, and inhibited the phosphorylation of Akt (Thr308). CONCLUSIONS: ZYJN could inhibit the tumor growth of CT26 colorectal cancer by promoting tumor fibrosis, suppressing angiogenesis, migration, and invasion and modulating the tumor immune microenvironment. ZYJN enhanced the efficacy and reduced the toxicity of chemotherapy drugs in combination therapy. Our findings provide evidence for the clinical application of ZYJN in cancer treatment.

Migration and redistribution of LNAPL in inclined stratified soil media.

Leakage of light non-aqueous phase liquid (LNAPL) into soil can cause serious environmental issues. In this study, a two-dimensional device with adjustable dip angles was designed to investigate the migration and redistribution of LNAPL in natural inclined stratified soil media by the light transmission visualization (LTV) technology. The captured experimental images were processed to obtain the diesel distribution based on gray value which could represent the LNAPL saturation distribution. LNAPL may not be able to penetrate through the fine-coarse interface due to the capillary barrier effects. In this case, the vertical and horizontal migration distances (V and H), contaminated area (S), as well as deviation angle (γ) of centroid increased with the dip angle. Increasing the leakage amount to more than 30 mL would result in LNAPL breakthrough at the 10°-inclined interface, leading to much larger V, H, S, and γ than those at 10 mL, while 20-mL LNAPL failed to break through. In the latter case, a lower leakage rate than 10 mL/min would cause larger H and γ but similar V or S in the long term. This study could enrich the understanding of LNAPL contamination in vadose zone, providing reference for the prediction and treatment in realistic inclined contaminated sites.

Computational study on persulfate activation by two-dimensional carbon materials with various nitrogen proportions for carbamazepine oxidation in wastewater: The essential role of graphitic N atoms.

Two-dimensional carbon materials with various N atom proportions (2D-CNMs) are constructed to clarify the optimal catalyst for carbamazepine (CBZ) oxidation and the inner mechanism for persulfate-based advanced oxidation processes (P-AOPs). Results show that peroxydisulfate (PDS) can be activated by all 2D-CNMs with the order of C3N > C71N > graphene > C2N > CN, while C3N is the only catalyst for peroxymonosulfate (PMS) activation. The C3N with the maximum graphitic N can activate PDS and PMS in a wide temperature range at any pH, and demonstrates the optimal CBZ oxidation performance. Notably, the graphitic N atoms promote P-AOPs from five aspects: (i) electron structure, (ii) electrical conductivity, (iii) electron transfer from persulfate to catalysts, (iv) electron jump of co-system before and after activation, (v) interaction between catalyst and persulfate. The most vigorous activity of C3N is attributed to the greatest number of graphitic N. This work clarifies the essential role of graphitic N atoms with implications for the catalyst design, and facilitates the environmental applications of P-AOPs for micropollutant abatement.

Toluene decomposition by non-thermal plasma assisted CoOx - γ-Al2O3: The relative contributions of specific energy input of plasma, Co3+ and oxygen vacancy.

Cobalt oxide (CoOx) is a common catalyst for plasma catalytic elimination of volatile organic compounds (VOCs). However, the catalytic mechanism of CoOx under radiation of plasma is still unclear, such as how the relative importance of the intrinsic structure of the catalyst (e.g., Co3+ and oxygen vacancy) and the specific energy input (SEI) of the plasma for toluene decomposition performance. CoOx - Î³-Al2O3 catalysts were prepared and evaluated by toluene decomposition performance. Changing the calcination temperature of the catalyst altered the content of Co3+ and oxygen vacancies in CoOx, resulting in different catalytic performance. The results of the artificial neural network (ANN) models presented that the relative importance of three reaction parameters (SEI, Co3+, and oxygen vacancy) on the mineralization rate and CO2 selectivity were as follows: SEI > oxygen vacancy > Co3+ , and SEI > Co3+ > oxygen vacancy, respectively. Oxygen vacancy is essential for mineralization rate, and CO2 selectivity is more dependent on Co3+ content. Furthermore, a possible reaction mechanism of toluene decomposition was proposed according to the analysis results of in-situ DRIFTS and PTR-TOF-MS. This work provides new ideas for the rational design of CoOx catalysts in plasma catalytic systems.

Modulation of Remote Epitaxial Heterointerface by Graphene-Assisted Attenuative Charge Transfer.

Remote epitaxy (RE), substrate polarity can "penetrate" two-dimensional materials (2DMs) and act on the epi-layer, showing a prospective universal growth strategy. However, essentially, the role that 2DMs plays in RE has not been deeply investigated so far. Here, the RE of single-crystal films on the weakest polarity/iconicity substrate is realized to reveal its essence physical properties. Graphene facilitates attenuative charge transfer (ACT) from a substrate to epi-layer to construct remote interactions. Interfacial atoms are assembled into "incommensurate" epitaxial relationships through graphene to reduce misfit dislocations in the epi-layer. Moreover, graphene reduces the atomic migration barrier, leading to a tendency toward a "layer-by-layer" growth mode. Such film growth mode is different with the conventional epitaxy (CE), and it is beneficial for the fast growth of epi-layers and the reduction of dislocations at coalescence boundaries. The insightful revelation of the role of graphene reveals the interface physics of RE and provides a more valuable guide to using 2DMs to expand three-dimensional materials (3DMs) for application in devices.

WSe2/g-C3N4 for an In Situ Photocatalytic Fenton-like System in Phenol Degradation.

An in situ photo-Fenton system can continuously generate H2O2 by photocatalysis, activating H2O2 in situ to form strong oxidizing ·OH radicals and degrading organic pollutants. A WSe2/g-C3N4 composite catalyst with WSe2 as a co-catalyst was successfully synthesized in this work and used for in situ photo-Fenton oxidation. The WSe2/g-C3N4 composite with 7% loading of WSe2 (CNW2) has H2O2 production of 35.04 µmol/L, which is fourteen times higher than pure g-C3N4. The degradation efficiency of CNW2 for phenol reached 67%. By constructing an in situ Fenton-system, the phenol degradation rate could be further enhanced to 90%. WSe2 can enhance the catalytic activity of CNW2 by increasing electron mobility and inhibiting the recombination of photogenerated electron-hole pairs. Moreover, the addition of Fe2+ activates the generated H2O2, thus increasing the amount of strong oxidative ·OH radicals for the degradation of phenol. Overall, CNW2 is a promising novel material with a high H2O2 yield and can directly degrade organic pollutants using an in situ photo-Fenton reaction.

Theoretical exploration of VOCs removal mechanism by carbon nanotubes through persulfate-based advanced oxidation processes: Adsorption and catalytic oxidation.

Carbon-catalyzed persulfate activation for the removal of gaseous volatile organic compounds (VOCs) has not been reported yet, and the corresponding fundamental mechanisms of VOCs adsorption and the subsequent VOCs degradation remain controversial. In this work, theoretical chemistry calculations were carried out to explore the VOCs removal mechanism by the persulfate-based advanced oxidation processes (P-AOPs) for VOCs removal over single walled carbon nanotubes (SWCNT). This study provided detailed theoretical insights into the SWCNT/P-AOPs for VOCs treatment in terms of adsorption, activation, mineralization, and diffusion of VOCs or peroxymonosulfate (PMS). Various VOCs were found to be preferentially adsorbed onto SWCNT, and the adsorption strength of VOCs was found to be significantly dependent on their polarizability. On the other side, PMS adsorbed on SWCNT could be efficiently activated through accepting π electron in the sp2 carbon matrix of SWCNT rather than the electrons at dangling bonds to generate •OH radicals attributed to the strong interaction between PMS and SWCNT. Formaldehyde was then taken as an example to evaluate the catalytic degradation pathways via SWCNT/P-AOPs. Under the attack of •OH radicals, the ultrafast degradation pathway of formaldehyde with no byproduct CO was identified with ultralow reaction energy barrier and large energy release. In addition, factors affecting the adsorption of organic compounds were identified and the detailed PMS activation pathway was present directly in this work. Above all, this work extended the carbons/P-AOPs system to VOCs abatement and presented systematic evidences for the essential mechanisms associated with VOCs adsorption and PMS activation by SWCNT, and the corresponding removal pathway and mechanism were also understood.

First-Principles Evaluation of Volatile Organic Compounds Degradation in Z-Scheme Photocatalytic Systems: MXene and Graphitic-CN Heterostructures.

It is a formidable challenge to use the traditional trial-and-error method to identify suitable catalysts for the photocatalytic degradation of volatile organic compounds (VOCs). In this work, by performing density functional theory calculations, we designed three Z-scheme g-CN/M2CO2 (M = Hf, Zr, and Sc) heterostructures, which not only exhibit favorable structure stability but also show promising ability for photocatalytic degradation of VOCs. The enhancement of the photocatalytic activity of these three Z-scheme systems can be ascribed to the low recombination rate of electron-hole pairs because photoelectrons migrated from the g-CN layer to the M2CO2 layer as well as the internal electric fields in the Z-scheme heterojunction. Among the three heterostructures, only g-CN/Zr2CO2 presents favorable spectra utilization under photoirradiation as well as the direct band gap. As a result, in the Z-scheme g-CN/Zr2CO2 heterostructure, the electrons in the conduction band of g-CN migrate to the holes in the valence band of the Zr2CO2 layer, which improves extraction and utilization of photogenerated electrons in the g-CN sheet. Moreover, the Z-scheme g-CN/Zr2CO2 system shows superior performance for photocatalytic VOC degradation in comparison with individual g-CN and Zr2CO2, which can be attributed to the enhanced VOC adsorption capacity as well as excellent ability to photoactivate O2 and H2O into •O2- and •OH radicals. Our findings pave a new promising way to facilitate the application of MXene-based materials for VOC photocatalytic degradation.

3D Printed Multi-Functional Hydrogel Microneedles Based on High-Precision Digital Light Processing.

Traditional injection and extraction devices often appear painful and cumbersome for patients. In recent years, polymer microneedles (MNs) have become a novel tool in the field of clinical medicine and health. However, the cost of building MNs into any shapes still remains a challenge. In this paper, we proposed hydrogel microneedles fabricated by high-precision digital light processing (H-P DLP) 3D printing system. Benefits from the sharp protuberance and micro-porous of the hydrogel microneedle, the microneedle performed multifunctional tasks such as drug delivery and detection with minimally invasion. Critical parameters for the fabrication process were analyzed, and the mechanical properties of MNs were measured to find a balance between precision and stiffness. Results shows that the stiffness and precision were significantly influenced by exposure time of each layer, and optimized printing parameters provided a balance between precision and stiffness. Bio-compatible MNs based on our H-P DLP system was able to execute drug injection and drug detection in our experiments. This work provided a low-cost and fast method to build MNs with 3D building, qualified the mechanical performance, drug injection, drug detection ability of MNs, and may be helpful for the potential clinical application.

Di'ao Xinxuekang Capsule, a Chinese Medicinal Product, Decreases Serum Lipids Levels in High-Fat Diet-Fed ApoE-/- Mice by Downregulating PCSK9.

Numerous risk factors are responsible for the development of atherosclerosis, for which an increased serum level of low-density lipoprotein cholesterol (LDL-C) is a driving force. By binding to the low-density lipoprotein cholesterol receptor (LDLR) and inducing LDLR degradation, proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a key role in cholesterol homeostasis regulation. The inducement of PCSK9 expression is also an important reason for statin intolerance. The Di'ao Xinxuekang (DXXK) capsule extracted from Dioscorea nipponica Makino is a well-known traditional Chinese herbal medicinal product used in atherosclerotic cardiovascular disease. Although DXXK has been widely used in atherosclerotic cardiovascular treatment for nearly 30 years, studies on the potential mechanisms of the lipid-lowering effect are very limited. The purpose of the present study was to demonstrate the possible involvement of the PCSK9/LDLR signaling pathway in the lipid-lowering and antiatherosclerotic effect of DXXK in high-fat diet-fed ApoE-/- mice. The results showed that DXXK treatment alleviated hyperlipidemia, fat accumulation, and atherosclerosis formation in ApoE-/- mice. Furthermore, changes in the expression of PCSK9 mRNA in liver tissue and the circulating PCSK9 level in ApoE-/- mice were both reversed after DXXK treatment, and upregulation of LDLR in the liver was also detected in the protein level in DXXK-treated mice. Our study is the first to show that DXXK could alleviate lipid disorder and ameliorate atherosclerosis with downregulation of the PCSK9 in high-fat diet-fed ApoE-/- mice, suggesting that DXXK may be a potential novel therapeutic treatment and may support statin action in the treatment of atherosclerosis.