Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 52
Filtrar
1.
Proc Natl Acad Sci U S A ; 121(20): e2318384121, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38713627

RESUMO

The reaction kinetics of photocatalytic CO2 reduction is highly dependent on the transfer rate of electrons and protons to the CO2 molecules adsorbed on catalytic centers. Studies on uncovering the proton effect in catalysts on photocatalytic activity of CO2 reduction are significant but rarely reported. In this paper, we, from the molecular level, revealed that the photocatalytic activity of CO2 reduction is closely related to the proton availability in catalysts. Specifically, four dinuclear Co(II) complexes based on Robson-type ligands with different number of carboxylic groups (-nCOOH; n = 0, 2, 4, 6) were designed and synthesized. All these complexes show photocatalytic activity for CO2 reduction to CO in a water-containing system upon visible-light illumination. Interestingly, the CO yields increase positively with the increase of the carboxylic-group number in dinuclear Co(II) complexes. The one containing -6COOH shows the best photocatalytic activity for CO2 reduction to CO, with the TON value reaching as high as 10,294. The value is 1.8, 3.4, and 7.8 times higher than those containing -4COOH, -2COOH, and -0COOH, respectively. The high TON value also makes the dinuclear Co(II) complex with -6COOH outstanding among reported homogeneous molecular catalysts for photocatalytic CO2 reduction. Control experiments and density functional theory calculation indicated that more carboxylic groups in the catalyst endow the catalyst with more proton relays, thus accelerating the proton transfer and boosting the photocatalytic CO2 reduction. This study, at a molecular level, elucidates that more carboxylic groups in catalysts are beneficial for boosting the reaction kinetics of photocatalytic CO2 reduction.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38362697

RESUMO

NADPH oxidase, as a major source of intracellular reactive oxygen species (ROS), assumes an important role in the immune response and oxidative stress response of the body. NADPH 9 oxidase 2 (NOX2) is the first and most representative member of the NADPH oxidase family, and its effects on the development of tumor cells are gaining more and more attention. Our previous study suggested that NCF4 polymorphism in p40phox, a key subunit of NOX2, affected the outcome of diffuse large B-cell lymphoma patients treated with rituximab. It hypothesized that NOX2-mediated ROS could enhance the cytotoxic effects of some anti-tumor drugs in favor of patients with tumors. Several reviews have summarized the role of NOX2 and its congeners-mediated ROS in anti-tumor therapy, but few studies focused on the relationship between the expression of NOX2 and anti-tumor drug resistance. In this article, we systematically introduced the NOX family, represented by NOX2, and a classification of the latest inhibitors and agonists of NOX2. It will help researchers to have a more rational and objective understanding of the dual role of NOX2 in tumor drug resistance and is expected to provide new ideas for oncology treatment and overcoming drug resistance in cancer.

3.
Chemistry ; 30(7): e202303345, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37964711

RESUMO

Homonuclear dual-atomic catalysts showcase unique electronic modulation due to their dual metal centres, providing new direction in development of efficient catalysts for CO2 electroreduction. This article highlights a few cutting-edge homonuclear dual-atomic catalysts, focusing on their inherent advantages in efficient and selective CO2 electroreduction, to spotlight the potential application of dual-atomic catalysts in CO2 electroreduction.

4.
Angew Chem Int Ed Engl ; 63(10): e202318735, 2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38108581

RESUMO

Covalent organic frameworks (COFs) have been widely studied in photocatalytic CO2 reduction reaction (CO2 RR). However, pristine COFs usually exhibit low catalytic efficiency owing to the fast recombination of photogenerated electrons and holes. In this study, we fabricated a stable COF-based composite (GO-COF-366-Co) by covalently anchoring COF-366-Co on the surface of graphene oxide (GO) for the photocatalytic CO2 reduction. Interestingly, in absolute acetonitrile (CH3 CN), GO-COF-366-Co shows a high selectivity of 94.4 % for the photoreduction of CO2 to formate, with a formate yield of 15.8 mmol/g, which is approximately four times higher than that using the pristine COF-366-Co. By contrast, in CH3 CN/H2 O (v : v=4 : 1), the main product for the photocatalytic CO2 reduction over GO-COF-366-Co is CO (96.1 %), with a CO yield as high as 52.2 mmol/g, which is also approximately four times higher than that using the pristine COF-366-Co. Photoelectrochemical experiments demonstrate the covalent bonding of COF-366-Co and GO to form the GO-COF-366-Co composite facilitates charge separation and transfer significantly, thereby accounting for the enhanced catalytic activity. In addition, theoretical calculations and in situ Fourier transform infrared spectroscopy reveal H2 O can stabilize the *COOH intermediate to further form a *CO intermediate via O-H(aq)⋅⋅⋅O(*COOH) hydrogen bonding, thus explaining the regulated photocatalytic performance.

5.
Artigo em Inglês | MEDLINE | ID: mdl-37979015

RESUMO

BACKGROUND: Abdominal aortic aneurysm (AAA) is a chronic vascular disease wherein the inflammation of vascular smooth muscle cells (VSMCs) plays a pivotal role in its development. Effectively mitigating AAA involves inhibiting VSMC inflammation. Agathis dammara (Lamb.) Rich, recognized for its robust anti-inflammatory and antioxidant attributes, has been employed as a traditional medicinal resource. Nonetheless, there is a dearth of information regarding the potential of Agathis dammara extract (AD) in attenuating AAA, specifically by diminishing vascular inflammation, notably VSMC inflammation. Furthermore, the active constituents of AD necessitate identification. AIM OF THE STUDY: This study sought to ascertain the efficacy of AD in reducing AAA, evaluate its impact on VSMC inflammation, and elucidate whether the monomer araucarone (AO) in AD acts as an active component against AAA. MATERIALS AND METHODS: The extraction of AD was conducted and subjected to analysis through High-Performance Liquid Chromatography (HPLC) and mass spectrometry. The isolation of the AO monomer followed, involving the determination of its content and purity. Subsequently, the effects of AD and AO on VSMC inflammation were assessed in vitro, encompassing an examination of inflammatory factors such as IL-6 and IL-18, as well as the activation of matrix metalloproteinase 9 (MMP9) in tumor necrosis factor-alpha (TNF-α)-stimulated VSMCs. To explore the inhibitory effects of AD/AO on AAA, C57BL/6J male mice were subjected to oral gavage (100 mg/kg) or intraperitoneal injection (50 mg/kg) of AD and AO in a porcine pancreatic elastase (PPE)-induced AAA model (14 days). This facilitated the observation of abdominal aorta dilatation, remodeling, elastic fiber disruption, and macrophage infiltration. Additionally, a three-day PPE mouse model was utilized to assess the effects of AD and AO (administered at 100 mg/kg via gavage) on acute inflammation and MMP9 expression in blood vessels. The mechanism by which AD/AO suppresses the inflammatory response was probed through the examination of NF-κB/NLRP3 pathway activation in VSMCs and aortas. RESULTS: Liquid Chromatography-Mass Spectrometry (LC-MS) revealed that AO constituted 15.36% of AD's content, with a purity of 96%. Subsequent pharmacological investigations of AO were conducted in parallel with AD. Both AD and AO exhibited the ability to inhibit TNF-α-induced VSMC inflammation and MMP production in vitro. Furthermore, both substances effectively prevented PPE-induced AAA in mice, whether administered through gavage or intraperitoneal injection, evidenced by decreased vascular diameter dilation, disruption of elastin fiber layers, and infiltration of inflammatory cells. In the three-day PPE mouse model, AD and AO mitigated the heightened expression of inflammatory factors and the elevated expression of MMP9 induced by PPE. The activation of the NF-κB/NLRP3 pathway in both VSMCs and aortas was significantly suppressed by treatment with AD or AO. CONCLUSIONS: Through suppressing NF-κB/NLRP3 pathway activation, AD effectively mitigates the inflammatory response in VSMCs, mitigates inflammation in aortas, prevents extracellular matrix degradation, and consequently impedes the progression of AAA. AO emerges as one of the active compounds in AD responsible for inhibiting VSMC inflammation and inhibiting AAA development.

6.
Front Pharmacol ; 14: 1265825, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37849728

RESUMO

Ulcerative colitis (UC) is a clinically common, progressive, devastating, chronic inflammatory disease of the intestine that is recurrent and difficult to treat. Nod-like receptor protein 3 (NLRP3) is a protein complex composed of multiple proteins whose formation activates cysteine aspartate protease-1 (caspase-1) to induce the maturation and secretion of inflammatory mediators such as interleukin (IL)-1ß and IL-18, promoting the development of inflammatory responses. Recent studies have shown that NLRP3 is associated with UC susceptibility, and that it maintains a stable intestinal environment by responding to a wide range of pathogenic microorganisms. The mainstay of treatment for UC is to control inflammation and relieve symptoms. Despite a certain curative effect, there are problems such as easy recurrence after drug withdrawal and many side effects associated with long-term medication. NLRP3 serves as a core link in the inflammatory response. If the relationship between NLRP3 and gut microbes and inflammation-associated factors can be analyzed concerning its related inflammatory signaling pathways, its expression status as well as specific mechanism in the course of IBD can be elucidated and further considered for clinical diagnosis and treatment of IBD, it is expected that the development of lead compounds targeting the NLRP3 inflammasome can be developed for the treatment of IBD. Research into the prevention and treatment of UC, which has become a hotbed of research in recent years, has shown that natural products are rich in therapeutic means, and multi-targets, with fewer adverse effects. Natural products have shown promise in treating UC in numerous basic and clinical trials over the past few years. This paper describes the regulatory role of the NLRP3 inflammasome in UC and the mechanism of recent natural products targeting NLRP3 against UC, which provides a reference for the clinical treatment of this disease.

7.
Proc Natl Acad Sci U S A ; 120(45): e2304179120, 2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37903265

RESUMO

The unexpected discovery of hot Jupiters challenged the classical theory of planet formation inspired by our solar system. Until now, the origin and evolution of hot Jupiters are still uncertain. Determining their age distribution and temporal evolution can provide more clues into the mechanism of their formation and subsequent evolution. Using a sample of 383 giant planets around Sun-like stars collected from the kinematic catalogs of the Planets Across Space and Time project, we find that hot Jupiters are preferentially hosted by relatively younger stars in the Galactic thin disk. We subsequently find that the frequency of hot Jupiters declines with age as [Formula: see text]. In contrast, the frequency of warm/cold Jupiters shows no significant dependence on age. Such a trend is expected from the tidal evolution of hot Jupiters' orbits, and our result offers supporting evidence using a large sample. We also perform a joint analysis on the planet frequencies in the stellar age-metallicity plane. The result suggests that the frequencies of hot Jupiters and warm/cold Jupiters, after removing the age dependence are both correlated with stellar metallicities as [Formula: see text] and [Formula: see text], respectively. Moreover, we show that the above correlations can explain the bulk of the discrepancy in hot Jupiter frequencies inferred from the transit and radial velocity (RV) surveys, given that RV targets tend to be more metal-rich and younger than transits.

8.
Inorg Chem ; 62(29): 11611-11617, 2023 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-37428154

RESUMO

The development of hierarchically porous metal-organic frameworks (MOFs) with high stability is desirable to expand their applications but remains challenging. Herein, an anionic sodalite-type microporous MOF (Yb-TTCA; TTCA3- = triphenylene-2,6,10-tricarboxylate) was synthesized, which shows outstanding catalytic activities for the cycloaddition of CO2 into cyclic carbonates. Moreover, the microporous Yb-TTCA can be transformed into a hierarchical micro- and mesoporous Yb-TTCA by water treatment with the mesopore sizes of 2 to 12 nm. The hierarchically porous Yb-TTCA (HP-Yb-TTCA) not only exhibits a high thermal stability up to 500 °C but also shows a high chemical stability in aqueous solutions with pH values ranging from 2 to 12. In addition, the HP-Yb-TTCA displays enhanced performance for the removal of organic dyes in comparison with microporous Yb-TTCA. This work provides a facile way to construct hierarchically porous MOF materials.

9.
Chem Soc Rev ; 52(9): 3170-3214, 2023 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-37070676

RESUMO

Catalysts featuring dinuclear metal sites are regarded as superior systems compared with their counterparts with mononuclear metal sites. The dinuclear metal sites in catalysts with appropriate spatial separations and geometric configurations can confer the dinuclear metal synergistic catalysis (DMSC) effect, and thus boost the catalytic performance, in particular for reactions involving multiple reactants, intermediates and products. In this review, we summarize the related reports on the design and synthesis of both homogeneous and heterogeneous dinuclear metal catalysts, and their applications in energy conversion reactions, including photo-/electro-catalytic hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), CO2 reduction reaction (CO2RR), and N2 reduction reaction (N2RR). Particularly, we focus on the analysis of the relationship between the catalyst structure and catalytic performances, where the design principles are presented. Finally, we discuss the challenges in the design and preparation of dinuclear metal catalysts with the DMSC effect and present a perspective on the future development of dinuclear metal catalysts in energy conversion. This review aims to comprehensively summarize the up-to-date research progress on the synthesis and energy-related application of dinuclear metal catalysts and provide guidance for designing energy-conversion catalysts with superior performances.

10.
Angew Chem Int Ed Engl ; 62(20): e202300507, 2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-36897282

RESUMO

The mismatched fast-electron-slow-proton process in the electrocatalytic oxygen evolution reaction (OER) severely restricts the catalytic efficiency. To overcome these issues, accelerating the proton transfer and elucidating the kinetic mechanism are highly sought after. Herein, inspired by photosystem II, we develop a family of OER electrocatalysts with FeO6 /NiO6 units and carboxylate anions (TA2- ) in the first and second coordination sphere, respectively. Benefiting from the synergistic effect of the metal units and TA2- , the optimized catalyst delivers superior activity with a low overpotential of 270 mV at 200 mA cm-2 and excellent cycling stability over 300 h. A proton-transfer-promotion mechanism is proposed by in situ Raman, catalytic tests, and theoretical calculations. The TA2- (proton acceptor) can mediate proton transfer pathways by preferentially accepting protons, which optimizes the O-H adsorption/activation process and reduces the kinetic barrier for O-O bond formation.

11.
Angew Chem Int Ed Engl ; 61(51): e202215187, 2022 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-36316808

RESUMO

Dual-atom catalysts (DACs) have emerged as efficient electrocatalysts for CO2 reduction owing to the synergistic effect between the binary metal sites. However, rationally modulating the electronic structure of DACs to optimize the catalytic performance remains a great challenge. Herein, we report the electronic structure modulation of three Ni2 DACs (namely, Ni2 -N7 , Ni2 -N5 C2 and Ni2 -N3 C4 ) by the regulation of the coordination environments around the dual-atom Ni2 centres. As a result, Ni2 -N3 C4 exhibits significantly improved electrocatalytic activity for CO2 reduction, not only better than the corresponding single-atom Ni catalyst (Ni-N2 C2 ), but also higher than Ni2 -N7 and Ni2 -N5 C2 DACs. Density functional theory (DFT) calculations revealed that the high electrocatalytic activity of Ni2 -N3 C4 for CO2 reduction could be attributed to the electronic structure modulation to the Ni centre and the resulted proper binding energies to COOH* and CO* intermediates.

12.
Proc Natl Acad Sci U S A ; 119(35): e2119267119, 2022 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-35998222

RESUMO

A carbazolide-bis(NHC) NiII catalyst (1; NHC, N-heterocyclic carbene) for selective CO2 photoreduction was designed herein by a one-stone-two-birds strategy. The extended π-conjugation and the strong σ/π electron-donation characteristics (two birds) of the carbazolide fragment (one stone) lead to significantly enhanced activity for photoreduction of CO2 to CO. The turnover number (TON) and turnover frequency (TOF) of 1 were ninefold and eightfold higher than those of the reported pyridinol-bis(NHC) NiII complex at the same catalyst concentration using an identical Ir photosensitizer, respectively, with a selectivity of ∼100%. More importantly, an organic dye was applied to displace the Ir photosensitizer to develop a noble-metal-free photocatalytic system, which maintained excellent performance and obtained an outstanding quantum yield of 11.2%. Detailed investigations combining experimental and computational studies revealed the catalytic mechanism, which highlights the potential of the one-stone-two-birds effect.

13.
Pharmaceutics ; 14(6)2022 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-35745830

RESUMO

Hypercholesterolemia is one of the independent risk factors for the development of cardiovascular diseases such as atherosclerosis. The treatment of hypercholesterolemia is of great significance to reduce clinical cardiovascular events and patient mortality. Simvastatin (SIM) and ezetimibe (EZE) are commonly used clinically as cholesterol-lowering drugs; however, their treatment efficacy is severely affected by their poor water solubility and low bioavailability. In this study, SIM and EZE were made into a co-amorphous system to improve their dissolution, oral bioavailability, storage stability, and cholesterol-lowering effects. The SIM-EZE co-amorphous solids (CO) were prepared successfully using the melt-quenched technique, and the physicochemical properties of CO were characterized accordingly, which exhibited improved physical stability and faster dissolution release profiles than their physical mixture (PM). In the pharmacokinetic study, the SIM-EZE CO or PM was given once by oral gavage, and mouse blood samples were collected retro-orbitally at multiple time points to determine the plasma drug concentrations. In the pharmacodynamic study, low-density lipoprotein receptor-deficient (LDLr-/-) mice were fed with a high-fat diet (HFD) for two weeks to establish a mouse model of hypercholesterolemia. Using PM as a control, we investigated the regulation of CO on plasma lipid levels in mice. Furthermore, the mice feces were collected to determine the cholesterol contents. Besides, the effect of EZE on the NPC1L1 mRNA expression level in the mouse intestines was also investigated. The pharmacokinetics results showed that the SIM-EZE CO has improved bioavailability compared to the PM. The pharmacodynamic studies showed that SIM-EZE CO significantly increased the cholesterol-lowering effects of the drugs compared to their PM. The total cholesterol excretion in the mouse feces and inhibitory effect on NCP1L1 gene expression in the mouse intestines after being given the SIM-EZE CO were more dramatic than the PM. Our study shows that the SIM-EZE CO prepared by the melt-quenched method can significantly improve the stability, bioavailability, and cholesterol-lowering efficacy with excellent development potential as a new drug formulation.

14.
Small ; 18(20): e2200332, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35451165

RESUMO

2D lamellar materials can offer high surface area and abundant reactive sites, thus showing an appealing prospect in photocatalytic hydrogen evolution. However, it is still difficult to build cost-efficient photocatalytic hydrogen evolution systems based on 2D materials. Herein, an in situ growth method is employed to build 2D/2D heterojunctions, with which 2D Ni-based metal-organic layers (Ni-MOLs) are closely grown on 2D porous CdS (P-CdS) nanosheets, affording traditional P-CdS/Ni-MOL heterojunction materials. Impressively, the optimized P-CdS/Ni-MOL catalyst exhibits superior photocatalytic hydrogen evolution performance, with an H2 yield of 29.81 mmol g-1 h-1 . This value is 7 and 2981 times higher than that of P-CdS and Ni-MOLs, respectively, and comparable to those of reported state of the art catalysts. Photocatalytic mechanism studies reveal that the enhanced photocatalytic performance can be attributed to the 2D/2D intimate interface between P-CdS and Ni-MOLs, which facilitates the fast charge carriers' separation and transfer. This work provides a strategy to develop 2D MOL-based photocatalysts for sustainable energy conversion.

15.
Proc Natl Acad Sci U S A ; 119(11): e2118278119, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35263220

RESUMO

SignificanceThe photosensitizer is one of the important components in the photocatalytic system. Molecular photosensitizers have well-defined structures, which is beneficial in revealing the catalysis mechanism and helpful for further structural design and performance optimization. However, separation and recycling of the molecular photosensitizers is a great problem. Loading them into/on two/three-dimensional supports through covalent bonds, electrostatic interactions, and supramolecular interactions is a method that enhances their separation and recycling capability. Nonetheless, the structures of the resulting composites are unclear. Thus, the development of highly crystalline heterogeneity methods for molecular photosensitizers, albeit greatly challenging, is meaningful and desirable in photocatalysis, through which heterogeneous photosensitizers with well-defined structures, definite catalysis mechanisms, and good catalytic performance would be expected.


Assuntos
Fármacos Fotossensibilizantes , Catálise , Estrutura Molecular , Fármacos Fotossensibilizantes/química
16.
Chem Commun (Camb) ; 58(15): 2512-2515, 2022 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-35094039

RESUMO

To avoid the agglomeration of iron NPs and improve the dispersion of Fe SAs, we employed a mixed-ligand strategy to regulate the iron content in PCN-224(ZnxFey) and PCN-222(ZnxFey). Thanks to the sublimation of Zn and the Kirkendall effect, uniform dispersions of Fe SAs with 1.04-1.06 wt% were obtained in the pyrolysis products Zn0.5Fe0.5-N-C-224 and Zn0.5Fe0.5-N-C-222 with excellent CO2 → CO activity, super-stability, and recyclability.

17.
Cardiovasc Drugs Ther ; 36(6): 1109-1119, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34491473

RESUMO

PURPOSE: Abdominal aortic aneurysm (AAA) rupture is one of the most common causes of mortality in cardiovascular diseases, but currently there is no approved drug for AAA treatment or prevention in the clinic. Naringenin (NGN) has been reported to have anti-AAA effects. However, water solubility and in vivo absorption of NGN are not satisfactory, which leads to its low bioavailability, thus affecting its pharmacological effects. In this project, the improving effects of isonicotinamide (INT) co-crystal and hydroxy propyl methyl cellulose (HPMC) or polyvinyl pyrrolidone (PVP) on the solubility, in vivo absorption, and anti-AAA effects of NGN were evaluated. METHODS: In the current study, co-crystals of naringenin-isonicotinamide (NGN-INT) were prepared, and effects of PVP or HPMC on precipitation rate, supersaturation, and bioavailability of NGN were explored. In addition, with or without HPMC supply, the effects of NGN-INT co-crystal on anti-AAA efficacy of NGN were investigated on an elastase-induced AAA mouse model, and the results were compared with the efficacy of the NGN crude drug. RESULTS: Our results demonstrate that NGN-INT formulation, compared to the NGN crude drug, enhanced the dissolution rate of NGN and significantly increased Cmax and AUC(0-∞) of NGN by 18 times and 1.97 times, respectively. Addition of PVP or HPMC in NGN-INT co-crystal further increased bioavailability of NGN in NGN-INT. The in vivo pharmacodynamic study showed that NGN-INT with HPMC significantly improved the inhibitory effects of NGN against AAA. CONCLUSION: NGN-INT significantly improved the absorption and aortic protective effects of NGN. The supersaturation-prolonging effect of HPMC further enhanced bioavailability and anti-AAA effects of NGN-INT.


Assuntos
Aneurisma da Aorta Abdominal , Camundongos , Animais , Aneurisma da Aorta Abdominal/tratamento farmacológico , Aneurisma da Aorta Abdominal/prevenção & controle , Derivados da Hipromelose/química , Solubilidade , Povidona/química
18.
Inorg Chem ; 60(19): 14924-14931, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34529419

RESUMO

The exploitation of highly stable and active catalysts for the conversion of CO2 into valuable fuels is desirable but is a great challenge. Herein, we report that the incorporation of chromophores into metal-organic frameworks (MOFs) could afford robust catalysts for efficient CO2 conversion. Specifically, a porous Nd(III) MOF (Nd-TTCA; TTCA3- = triphenylene-2,6,10-tricarboxylate) was constructed by incorporating one-dimensional Nd(CO2)n chains and TTCA3- ligands, which exhibits a very high stability, retaining its framework not only in the air at 300 °C for 2 h but also in boiling aqueous solutions at pH 1-12 for 7 days. More importantly, Nd-TTCA has achieved a 5-fold improvement in photocatalytic activity for reducing CO2 to HCOOH and a 10-fold improvement in catalytic activity for the cycloaddition of CO2 into cyclic carbonate in comparison to those of H3TTCA itself. This work gives a new strategy to design efficient artificial crystalline catalysts for CO2 conversion.

19.
Angew Chem Int Ed Engl ; 60(1): 409-414, 2021 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-32897636

RESUMO

It is common that different crystal facets in metal and metal oxide nanocrystals display different catalytic performances, whereas such phenomena have been rarely documented in metal-organic frameworks (MOFs). Herein, we demonstrate for the first time that a nickel metal-organic layer (MOL) exposing rich (100) crystal facets (Ni-MOL-100) shows a much higher photocatalytic CO2 -to-CO activity than the one exposing rich (010) crystal facets (Ni-MOL-010) and its bulky counterpart (bulky Ni-MOF), with a catalytic activity up to 2.5 and 4.6 times more active than Ni-MOL-010 and bulky Ni-MOF, respectively. Theoretical studies reveal that the two coordinatively unsaturated NiII ions with a close distance of 3.50 Šon the surface of Ni-MOL-100 enables synergistic catalysis, leading to more favorable energetics in CO2 reduction than that of Ni-MOL-010.

20.
Sci Adv ; 6(2): eaax9976, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31950081

RESUMO

Revealing the contribution of π-π stacking interactions in supramolecular assembly is important for understanding the intrinsic nature of molecular assembly fundamentally. However, because they are much weaker than covalent bonds, π-π stacking interactions are usually ignored in the construction of porous materials. Obtaining stable porous materials that are only dependent on π-π stacking interactions, despite being very challenging, could address this concern. Here, we present a porous supramolecular framework (π-1) stabilized only by intermolecular π-π stacking interactions. π-1 shows good thermal and chemical stability not only in various organic solvents but also in aqueous solution in a broad pH range. Furthermore, featuring one-dimensional channels with dangling thiolate groups, π-1 exhibits excellent Hg2+ removal performance, with adsorption capacity as high as 786.67 mg g-1 and an adsorption ratio as high as 99.998%. In addition, π-1 also shows high adsorption selectivity to Hg2+ in the presence of a series of interfering ions.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA