In situ formation of ZnOx species for efficient propane dehydrogenation.

Propane dehydrogenation (PDH) to propene is an important alternative to oil-based cracking processes, to produce this industrially important platform chemical1,2. The commercial PDH technologies utilizing Cr-containing (refs. 3,4) or Pt-containing (refs. 5-8) catalysts suffer from the toxicity of Cr(VI) compounds or the need to use ecologically harmful chlorine for catalyst regeneration9. Here, we introduce a method for preparation of environmentally compatible supported catalysts based on commercial ZnO. This metal oxide and a support (zeolite or common metal oxide) are used as a physical mixture or in the form of two layers with ZnO as the upstream layer. Supported ZnOx species are in situ formed through a reaction of support OH groups with Zn atoms generated from ZnO upon reductive treatment above 550 °C. Using different complementary characterization methods, we identify the decisive role of defective OH groups for the formation of active ZnOx species. For benchmarking purposes, the developed ZnO-silicalite-1 and an analogue of commercial K-CrOx/Al2O3 were tested in the same setup under industrially relevant conditions at close propane conversion over about 400 h on propane stream. The developed catalyst reveals about three times higher propene productivity at similar propene selectivity.

PB-LKS: a python package for predicting phage-bacteria interaction through local K-mer strategy.

Bacteriophages can help the treatment of bacterial infections yet require in-silico models to deal with the great genetic diversity between phages and bacteria. Despite the tolerable prediction performance, the application scope of current approaches is limited to the prediction at the species level, which cannot accurately predict the relationship of phages across strain mutants. This has hindered the development of phage therapeutics based on the prediction of phage-bacteria relationships. In this paper, we present, PB-LKS, to predict the phage-bacteria interaction based on local K-mer strategy with higher performance and wider applicability. The utility of PB-LKS is rigorously validated through (i) large-scale historical screening, (ii) case study at the class level and (iii) in vitro simulation of bacterial antiphage resistance at the strain mutant level. The PB-LKS approach could outperform the current state-of-the-art methods and illustrate potential clinical utility in pre-optimized phage therapy design.

Acute brain injury increases pulmonary capillary permeability via sympathetic activation-mediated high fluid shear stress and destruction of the endothelial glycocalyx layer.

Neurogenic pulmonary edema secondary to acute brain injury (ABI) is a common and fatal disease condition. However, the pathophysiology of brain-lung interactions is incompletely understood. This study aims to investigate whether sympathetic activation-mediated high fluid shear stress after ABI would damage pulmonary endothelial glycocalyx thus leading to increased pulmonary capillary permeability. The tricuspid annular plane systolic excursion (TAPSE) was detected in a rat model of controlled cortical impact (CCI) and CCI + transection of the cervical sympathetic trunk (TCST). Changes in pulmonary capillary permeability were assessed by analyzing the Evans blue, measuring the dry/wet weight ratio of the lungs and altering protein levels in the bronchoalveolar lavage fluid (BALF). The parallel-plate flow chamber system was used to simulate the fluid shear stress in vitro. Western blotting and immunofluorescence staining were used to determine the expression levels of hyaluronan-binding protein (CEMIP), syndecan-1 and tight junction proteins (TJPs, including claudin-5 and occludin). TCST could restrain cardiac overdrive and sympathetic activation in a rat model of CCI. Compared to the CCI group, the CCI + TCST group showed a reduction of CEMPI (which degrades hyaluronic acid), along with an increase of syndecan-1 and TJPs. CCI + TCST group presented decreasing pulmonary capillary permeability. In vitro, high shear stress (HSS) increased the expression of CEMIP and reduced syndecan-1 and TJPs, which was coordinated with the results in vivo. Our findings show that sympathetic activation-mediated high fluid shear stress after ABI would damage pulmonary endothelial glycocalyx thus leading to increased pulmonary capillary permeability.

Benchmarking boron cluster calculations: Establishing reliable geometrical and energetic references for Bn (n = 1-4).

Using full configuration interaction (FCI) and multi-reference configuration interaction methods (MRCI), reliable geometrical and energetic references for Bn (n = 1-4) clusters were established. The accuracy of the computed results was confirmed by comparison with available experimental data. Benchmark calculations indicated that B97D3, B97D, VSXC, HCTH407, BP86 and CCSD(T) methods provided reasonable results for structural parameters, with mean absolute error (MAEs) within 0.020 Å. Among the tested density functional theory (DFT) methods, the VSXC functional showed the best performance in predicting the relative energies of B1 B4 with a MAE of 12.8 kJ mol-1 . Besides, B1B95, B971, TPSS, B3LYP, and BLYP functionals exhibited reasonable performance with MAE values of less than 15.0 kJ mol-1 . T1 diagnostic values between 0.035 and 0.109 at the CCSD(T) level revealed strong correlations in B2 B4 clusters, highlighting the need for caution in using CCSD(T) as an energy reference for small boron clusters. The methods of CCSDT, CCSDT(Q) and CCSDT[Q], which incorporate three-electron and four-electron excitations, effectively improved the accuracy of the energy calculations.

Facile Construction of CuFe-Based Metal Phosphides for Synergistic NOx -Reduction to NH3 and Zn-Nitrite Batteries in Electrochemical Cell.

The electrocatalytic nitrite/nitrate reduction reaction (eNO2RR/eNO3RR) offer a promising route for green ammonia production. The development of low cost, highly selective and long-lasting electrocatalysts for eNO2RR/eNO3RR is challenging. Herein, a method is presented for constructing Cu3P-Fe2P heterostructures on iron foam (CuFe-P/IF) that facilitates the effective conversion of NO2 - and NO3 - to NH3. At -0.1 and -0.2 V versus RHE (reversible hydrogen electrode), CuFe-P/IF achieves a Faradaic efficiency (FE) for NH3 production of 98.36% for eNO2RR and 72% for eNO3RR, while also demonstrating considerable stability across numerous cycles. The superior performance of CuFe-P/IF catalyst is due tothe rich Cu3P-Fe2P heterstuctures. Density functional theory calculations have shed light on the distinct roles that Cu3P and Fe2P play at different stages of the eNO2RR/eNO3RR processes. Fe2P is notably active in the early stages, engaging in the capture of NO2 -/NO3 -, O─H formation, and N─OH scission. Conversely, Cu3P becomes more dominant in the subsequent steps, which involve the formation of N─H bonds, elimination of OH* species, and desorption of the final products. Finally, a primary Zn-NO2 - battery is assembled using CuFe-P/IF as the cathode catalyst, which exhibits a power density of 4.34 mW cm-2 and an impressive NH3 FE of 96.59%.

Fundamental Structural and Electronic Understanding of Palladium Catalysts on Nitride and Oxide Supports.

The nature of the support can fundamentally affect the function of a heterogeneous catalyst. For the novel type of isolated metal atom catalysts, sometimes referred to as single-atom catalysts, systematic correlations are still rare. Here, we report a general finding that Pd on nitride supports (non-metal and metal nitride) features a higher oxidation state compared to that on oxide supports (non-metal and metal oxide). Through thorough oxidation state investigations by X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), CO-DRIFTS, and density functional theory (DFT) coupled with Bader charge analysis, it is found that Pd atoms prefer to interact with surface hydroxyl group to form a Pd(OH)x species on oxide supports, while on nitride supports, Pd atoms incorporate into the surface structure in the form of Pd-N bonds. Moreover, a correlation was built between the formal oxidation state and computational Bader charge, based on the periodic trend in electronegativity.

Boosting Catalytic Selectivity through a Precise Spatial Control of Catalysts at Pickering Droplet Interfaces.

Exploration of new methodologies to tune catalytic selectivity is a long-sought goal in catalytic community. In this work, oil-water interfaces of Pickering emulsions are developed to effectively regulate catalytic selectivity of hydrogenation reactions, which was achieved via a precise control of the spatial distribution of metal nanoparticles at the droplet interfaces. It was found that Pd nanoparticles located in the inner interfacial layer of Pickering droplets exhibited a significantly enhanced selectivity for p-chloroaniline (up to 99.6%) in the hydrogenation of p-chloronitrobenzene in comparison to those in the outer interfacial layer (63.6%) in pure water (68.5%) or in pure organic solvents (46.8%). Experimental and theoretical investigations indicated that such a remarkable interfacial microregion-dependent catalytic selectivity was attributed to the microenvironments of the coexistence of water and organic solvent at the droplet interfaces, which could provide unique interfacial hydrogen-bonding interactions and solvation effects so as to alter the adsorption patterns of p-chloronitrobenzene and p-chloroaniline on the Pd nanoparticles, thereby avoiding the unwanted contact of C-Cl bonds with the metal surfaces. Our strategy of precise spatial control of catalysts at liquid-liquid interfaces and the unprecedented interfacial effect reported here not only provide new insights into the liquid-liquid interfacial reactions but also open an avenue to boost catalytic selectivity.

The Addition of an Ultra-Small Amount of Black Phosphorous Quantum Dots Endow Self-Healing Polyurethane with a Biomimetic Intelligent Response.

This study explores new applications of black phosphorus quantum dots (BPQDs) by adding them to self-healing material systems for the first time. Self-healing polyurethane with an ultra-small amount of BPQDs has biomimetic intelligent responsiveness and achieves balance between its mechanical and self-healing properties. By adding 0.0001 wt% BPQDs to self-healing polyurethane, the fracture strength of the material increases from 3.0 to 12.3 MPa, and the elongation at break also increases from 750% to 860%. Meanwhile, the self-healing efficiency remains at 98%. The addition of BPQDs significantly improves the deformation recovery ability of the composite materials and transforms the surface of self-healing polyurethane from hydrophilic to hydrophobic, making it suitable for applications in fields such as electronic skin and flexible wearable devices. This study provides a simple and feasible strategy for endowing self-healing materials with biomimetic intelligent responsiveness using a small amount of BPQDs.

Prognostic value of fibrinogen-to-albumin ratio combined with coronary calcification score in patients with suspected coronary artery disease.

OBJECTIVE: The aim of this work was to evaluate the predictive value of FAR combined with CACS for MACCEs. BACKGROUND: The fibrinogen-albumin-ratio (FAR), a novel biomarker of inflammation, is associated with the severity of coronary artery disease (CAD). Coronary calcification score (CACS) is associated with the severity of coronary stenosis and is closely related to the prognosis of CAD patients. What is the prognostic value of FAR in patients with chest pain, which has not been reported. This study aims to evaluate the relationship between CACS and FAR and their impact on prognosis in patients with suspected CAD. METHODS: We used information from 12,904 individuals who had coronary computed tomography angiography (CTA) for chest pain and tracked down any significant adverse cardiac and cerebrovascular events (MACCEs). The following formula was used to calculate FAR: fibrinogen (g/L)/albumin (g/L). Patients were separated into groups with greater levels of FAR (FAR-H) and lower levels of FAR (FAR-L) in accordance with the ideal cut-off value of FAR for MACCEs prediction. In addition, patients were divided into three groups based on their CACS scores (CACS ≤ 100, 100 < CACS ≤ 400, and CACS > 400). RESULTS: 4946 patients [62(55-71) years, 64.4% male] were ultimately enrolled in the present study. During follow-up, a total of 234 cases (4.7%) of MACCEs were documented. Linear regression analysis results showed that CACS (R2 = 0.004, Standard ß = 0.066, P < 0.001) was positively associated with FAR in patients with chest pain.Compared to ones with FAR-L, FAR-H had an increased risk for MACCEs (adjusted HR 1.371(1.053-1.786) P = 0.019). Multivariate Cox regression showed that age (adjusted HR 1.015 95% CI 1.001-1.028;p = 0.03), FAR (adjusted HR 1.355 95% CI 1.042-1.763;p = 0.023),FBG (adjusted HR 1.043 95% CI 1.006-1.083;p = 0.024) and CACS (adjusted HR 1.470 95% CI 1.250-1.727;p < 0.001) were the independent risk factors for MACCEs. The FAR and CACS significantly improved MACCEs risk stratification, contributing to substantial net reclassification improvement ( NRI 0.122, 95% CI 0.054-0.198, P < 0.001) and integrated discrimination improvement(IDI 0.011, 95% CI 0.006-0.017, P < 0.001). CONCLUSION: FAR was an independent risk factor for MACCEs. The results showed that CACS was positively associated with FAR in patients with suspected CAD. A higher level of FAR and heavier coronary calcification burden was associated with worse outcomes among patients with suspected CAD. FAR and CACS improved the risk identification of patients with suspected CAD, leading to a significant reclassification of MACCEs.

MicroRNA-4691-3p inhibits the inflammatory response by targeting STING in human dental pulp cells: A laboratory investigation.

AIM: The regulation of human dental pulp inflammation is not fully understood. This study aims to investigate the effect of miR-4691-3p on the cGAS-STING signalling cascade and its downstream cytokines production in human dental pulp cells (HDPCs). METHODOLOGY: Normal dental pulp tissue and pulp tissue with irreversible pulpitis from third molars were collected. HDPCs were isolated from pulp tissue. The expression of STING mRNA and miR-4691-3p was measured by quantitative real-time PCR. Bioinformatic computation via TargetScanHuman 8.0 and a luciferase reporter assay was used to identify the targets of miR-4691-3p. A miR-4691-3p mimic and inhibitor were used to upregulate or downregulate miR-4691-3p expression in HDPCs. HDPCs were transfected with c-di-AMP, c-di-GMP, cGAMP, interferon stimulatory DNA (ISD) and bacterial genomic DNA. Immunoblot was performed to detect the phosphorylation of TBK1, p65 and IRF3. Enzyme-linked immunoassay was performed to detect the cytokines including IFN-ß, TNF or IL-6 downstream of cGAS-STING. RESULTS: MiR-4691-3p expression was increased in human dental pulp tissue with irreversible pulpitis. Treatment of HDPCs using recombinant human IFN-ß, TNF or IL-6 also upregulated miR-4691-3p. The bioinformatic prediction and luciferase reporter assay confirmed that STING was a direct target of miR-4691-3p. The miR-4691-3p mimic suppressed STING expression, the phosphorylation of TBK1, p65 and IRF3, and the IFN-ß, TNF or IL-6 production. In contrast, the miR-4691-3p inhibitor enhanced the STING expression, the phosphorylation of TBK1, p65 and IRF3 and the IFN-ß, TNF or IL-6 production. CONCLUSIONS: MiR-4691-3p negatively regulates the cGAS-STING pathway by directly targeting STING. This provides insight to utilize miRNA-dependent regulatory effect to treat endodontic disease as well as STING-dependent systemic inflammatory disease.

Iridium-Catalyzed Domino Hydroformylation/Hydrogenation of Olefins to Alcohols: Synergy of Two Ligands.

A novel one-pot iridium-catalyzed domino hydroxymethylation of olefins, which relies on using two different ligands at the same time, is reported. DFT computation reveals different activities for the individual hydroformylation and hydrogenation steps in the presence of mono- and bidentate ligands. Whereas bidentate ligands have higher hydrogenation activity, monodentate ligands show higher hydroformylation activity. Accordingly, a catalyst system is introduced that uses dual ligands in the whole domino process. Control experiments show that the overall selectivity is kinetically controlled. Both computation and experiment explain the function of the two optimized ligands during the domino process.

A Cross-Species Reactive TIGIT-Blocking Antibody Fc Dependently Confers Potent Antitumor Effects.

The T cell immunoreceptor with Ig and ITIM domains (TIGIT) has been shown to exert inhibitory roles in antitumor immune responses. In this study, we report the development of a human mAb, T4, which recognizes both human and mouse TIGIT and blocks the interaction of TIGIT with its ligand CD155 in both species. The T4 Ab targets the segment connecting F and G strands of TIGIT's extracellular IgV domain, and we show in studies with mouse tumor models that the T4 Ab exerts strong antitumor activity and induces durable immune memory against various tumor types. Mechanistically, we demonstrate that the T4 Ab's antitumor effects are mediated via multiple immunological impacts, including a CD8+ T immune response and Fc-mediated effector functions, through NK cells that cause significant reduction in the frequency of intratumoral T regulatory cells (Tregs). Notably, this Treg reduction apparently activates additional antitumor CD8+ T cell responses, targeting tumor-shared Ags that are normally cryptic or suppressed by Tregs, thus conferring cross-tumor immune memory. Subsequent engineering for Fc variants of the T4 Ab with enhanced Fc-mediated effector functions yielded yet further improvements in antitumor efficacy. Thus, beyond demonstrating the T4 Ab as a promising candidate for the development of cancer immunotherapies, our study illustrates how the therapeutic efficacy of an anti-TIGIT Ab can be improved by enhancing Fc-mediated immune effector functions. Our insights about the multiple mechanisms of action of the T4 Ab and its Fc variants should help in developing new strategies that can realize the full clinical potential of anti-TIGIT Ab therapies.

Mesoporous ZnO nanosheet as gas sensor for sensitive triethylamine detection.

In this paper, mesoporous ZnO nanosheets were synthesized by the hydrothermal method using polystyrene-polyacrylic acid (PS-PAA) as the template. The morphology, structure, and composition of the samples were characterized by SEM, TEM, XRD, and XPS, and the physical properties of the samples were tested by N2 adsorption-desorption curve. The results showed that the mesoporous ZnO nanosheets presented a flower-like appearance. Each flower is composed of flake petals which consist of nanoparticles of different sizes, with a large specific surface area. Gas sensitivity test results show that the ZnO gas sensor has good triethylamine (TEA) sensing performance. Its response to 50 ppm TEA can reach 43.771, and the detection limit is as low as 1 ppm, showing the characteristics of rapid response/recovery.

H2O2-responsive VEGF/NGF gene co-delivery nano-system achieves stable vascularization in ischemic hindlimbs.

Peripheral vascular disease (PVD) is a common clinical manifestation of atherosclerosis. Vascular endothelial growth factor (VEGF) gene therapy is a promising approach for PVD treatment. However, due to single-gene therapy limitations and high H2O2 pathological microenvironment, VEGF gene therapy are not as expectations and its clinical application are limited. Synergistic effects of Nerve factors and vascular factors in angiogenesis have attracted attention in recent years. In this study, VEGF and nerve growth factor (NGF) genes co-delivery nanoparticles (VEGF/NGF-NPs) were prepared by using H2O2 responsive 6s-PLGA-Po-PEG as a carrier. 6s-PLGA-Po-PEG could react with H2O2 specifically due to the internal peroxalate bond. Angiogenic effects of VEGF/NGF-NPs has been evaluated in cells and hindlimb ischemia mice model. Results showed that VEGF/NGF-NPs promoted VEGF and NGF co-expression simultaneously, eliminated excessive H2O2, strengthened reactions between SH-SY5Ys and HUVECs, and finally enhanced migration, tube formation, proliferation and H2O2 damage resistance of HUVECs. VEGF/NGF-NPs also recovered blood perfusion, promoted the expression of VEGF, NGF, eNOS and NO, and enhanced vascular coverage of pericytes. Treatment effects of VEGF/NGF-NPs may related to VEGF/eNOS/NO pathway. Altogether, VEGF/NGF-NPs eliminated excessive H2O2 while achieving gene co-delivery, and promoted stable angiogenesis. It's a promising way for PVD treatment by using VEGF/NGF-NPs.

Red blood cell biomimetic nanoparticle with anti-inflammatory, anti-oxidative and hypolipidemia effect ameliorated atherosclerosis therapy.

A main pathogenic factor of atherosclerosis is the local oxidative stress microenvironment. Probucol (PU) has anti-inflammatory, antioxidative and hypolipidemic effects, showing great potential to treat atherosclerosis. However, its low bioavailability limits its development. Herein, PU was encapsulated to form RP-PU with star-shaped polymers and red blood cell membranes. Star-shaped polymers show lower solution viscosity, a smaller hydrodynamic radius and a higher drug loading content than linear polymers. RP-PU had a good sustained-release effect and excellent biocompatibility. RP-PU can be efficiently internalized by cells to improve biodistribution. ApoE-/- mice were treated with RP-PU, and the contents of lipids and related metabolic enzymes were effectively reduced. The collagen fibers in the aortic root sections were reduced by RP-PU compared with control and PU. Moreover, RP-PU inhibited foam cell formation, decreased ICAM-1 and MCP-1 expression and delayed lesion formation. Consequently, RP-PU biomimetic nanoparticles can be developed as an anti-atherosclerotic nanotherapeutic.

The induction of inflammation by the cGAS-STING pathway in human dental pulp cells: A laboratory investigation.

AIM: To explore the presence of the cGAS-STING inflammatory pathway in human pulp tissue and human dental pulp cells (HDPCs). METHODOLOGY: Pulp tissue was collected from freshly extracted human healthy third molars or third molars with irreversible pulpitis. Quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunoassay (ELISA) were performed to assess IFN-ß, TNF and IL-6. Human dental pulp cells prepared from healthy human pulp tissues were transfected with interferon stimulatory DNA (ISD), bacterial genomic DNA, bacterial cyclic dinucleotides c-di-AMP, c-di-GMP or host cyclic dinucleotide cGAMP. SiRNA was used to knock down the endogenous cGAS or STING. G140 and H-151 were used to inhibit cGAS and STING respectively. Amlexanox and BAY 11-7082 were used to inhibit TBK1 and NF-κB respectively. qRT-PCR and ELISA were performed to detect the level of IFN-ß, TNF and IL-6. Western blot was performed to evaluate the TBK1, IRF3 and p65 phosphorylation. The Student's t-test and one-way anova were used for statistical analysis. RESULTS: IFN-ß, TNF and IL-6 were up-regulated in the inflamed human dental pulp tissue. CGAS and STING mRNA were increased in the inflamed human dental pulp tissue and detected in HDPCs prepared from healthy human pulp tissues. ISD transfection induced TBK1, IRF3 and p65 phosphorylation as well as IFN-ß, TNF and IL-6 production. IFN-ß, TNF and IL-6 production were also induced by transfection of bacterial and host cyclic dinucleotides or bacteria DNA. ISD or bacteria DNA transfection elevated the intracellular levels of cGAMP. Knock-down of cGAS or STING, as well as using cGAS inhibitor G140 or STING inhibitor H-151 abolished the IFN-ß, TNF and IL-6 production induced by ISD transfection. Knock-down of STING or using STING inhibitor H-151 abolished the IFN-ß, TNF and IL-6 induction by transfection of bacterial and host cyclic dinucleotides. Both Amlexanox and BAY 11-7082 inhibited IFN-ß, TNF and IL-6 production triggered by ISD and cyclic dinucleotides transfection. CONCLUSIONS: Human dental pulp cells expressed an intact cGAS-STING signalling axis. The cGAS-STING signalling axis may play an important role in pulp inflammation and immune defence.

Asymmetric Double Hydroxycarbonylation of Alkynes to Chiral Succinic Acids Enabled by Palladium Relay Catalysis.

A Pd-catalyzed asymmetric double hydroxycarbonylation of terminal alkynes was developed by using relay catalysis, providing a highly efficient route to chiral succinic acids (41 examples, 76-94 %, 94-99 % ee). Key to success was the combinatorial use of a Pd precursor with two distinct phosphine ligands in one pot. The synthetic utilities of this protocol were showcased in the facile synthesis of key intermediates for chiral pharmaceuticals.

The transcription factor ZFHX3 is crucial for the angiogenic function of hypoxia-inducible factor 1α in liver cancer cells.

Angiogenesis is a hallmark of tumorigenesis, and hepatocellular carcinoma (HCC) is hypervascular and therefore very dependent on angiogenesis for tumor development and progression. Findings from previous studies suggest that in HCC cells, hypoxia-induced factor 1α (HIF1A) and zinc finger homeobox 3 (ZFHX3) transcription factors functionally interact in the regulation of genes in HCC cells. Here, we report that hypoxia increases the transcription of the ZFHX3 gene and enhances the binding of HIF1A to the ZFHX3 promoter in the HCC cell lines HepG2 and Huh-7. Moreover, ZFHX3, in turn, physically associated with and was functionally indispensable for HIF1A to exert its angiogenic activity, as indicated by in vitro migration and tube formation assays of human umbilical vein endothelial cells (HUVECs) and microvessel formation in xenograft tumors of HCC cells. Mechanistically, ZFHX3 was required for HIF1A to transcriptionally activate the vascular endothelial growth factor A (VEGFA) gene by binding to its promoter. Functionally, down-regulation of ZFHX3 in HCC cells slowed their tumor growth, and addition of VEGFA to conditioned medium from ZFHX3-silenced HCC cells partially rescued the inhibitory effect of this medium on HUVEC tube formation. In human HCC, ZFHX3 expression was up-regulated, and this up-regulation correlated with both HIF1A up-regulation and worse patient survival, confirming a functional association between ZFHX3 and HIF1A in human HCC. We conclude that ZFHX3 is an angiogenic transcription factor that is integral to the HIF1A/VEGFA signaling axis in HCC cells.

Double-layer capsule of mesoporous ZnO@SnO2 for sensitive detection of triethylamine.

To overcome obstacles such as low response and poor selectivity of pure ZnO and SnO2 gas sensors, the ZnO@SnO2 sensor was synthesized by hydrothermal synthesis. The samples were characterized by XRD, XPS, SEM, HRTEM, N2 adsorption-desorption and other techniques. The results show that ZnO@SnO2 forms an n-n-type heterostructure and presents a double-layer capsule with a size of 0.5-4 µm. The results show that compared with pure ZnO and SnO2, the ZnO@SnO2 sensor exhibits a higher response (138.9) to 50 ppm triethylamine (TEA) at 152°C, which is 19.56 times that of the pure ZnO sensor and 21.7 times that of the SnO2 sensor. It has a short response/recovery time (11/11 s), excellent selectivity and cycling stability. Compared with other volatile organic compounds or gases, it has higher selectivity for TEA detection.