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1.
Angew Chem Int Ed Engl ; 63(6): e202316858, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38095801

RESUMO

Nanocatalytic tumor therapy based on Fenton nanocatalysts has attracted considerable attention because of its therapeutic specificity, enhanced outcomes, and high biocompatibility. Nevertheless, the rate-determining step in Fenton chemistry, which involves the transition of a high-valence metallic center (FeIII ) to a Fenton-active low-valence metallic center (FeII ), has hindered advances in nanocatalyst-based therapeutics. In this study, we constructed mesoporous single iron atomic nanocatalysts (mSAFe NCs) by employing catechols from dopamine to coordinate and isolate single iron atoms. The catechols also serve as reductive ligands, generating a field-effect-based cocatalytic system that instantly reduces FeIII species to FeII species within the mSAFe NCs. This self-motivated cocatalytic strategy enabled by mSAFe NCs accelerates the kinetics of the Fenton catalytic reaction, resulting in remarkable performance for nanocatalytic tumor therapy both in vitro and in vivo.


Assuntos
Compostos Férricos , Neoplasias , Humanos , Ferro , Neoplasias/tratamento farmacológico , Compostos Ferrosos , Catecóis , Peróxido de Hidrogênio , Catálise
2.
J Microsc ; 293(1): 3-19, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37874017

RESUMO

Thirty-three porcelain shards (28 Ru ware and 5 Ru-type ware) unearthed from Qinglingsi kiln and 31 celadon fragments from Zhanggongxiang kiln were studied systematically for tracing their correlation and difference in glaze and body characteristics through a variety of characterisation methods. Samples without HF corrosion were applied to achieve the microstructure and composition details by SEM and TEM. Results exhibited that there were certain similarities between Ru ware, Ru-type ware and Zhanggongxiang kiln celadon in glaze colour and thickness, body features, fracture structure; however, they showed obvious differences in body thickness, chemical composition of glaze and body, phase constituents and microstructure of glaze. Plentiful needle-like diopside were widely distributed in Zhanggongxiang kiln celadon glazes, while this type of crystals was only existed in few Ru and Ru-type ware glazes with small content. Besides, a large amount of residual quartz was present over the Ru ware glazes, which could have relation to the incorporation of agate. The liquid-liquid phase separation structure (Ca-rich droplets and Si-rich matrix) was generated within the interspaces of anorthite clusters or around the brims of anorthite needles or columns. The occurrence of phase separation was generally accompanied by Al2 O3 consumption, but suppressed in the areas far from anorthite due to the rise of Al2 O3 content, indicating that Al2 O3 was the most sensitive constituent for this glaze behaviour. The distinguished size, shape and distribution of phase-separated droplets or interconnected structures were closely associated with the scale and crowding level of anorthite crystallisation.

3.
Artigo em Inglês | MEDLINE | ID: mdl-37279101

RESUMO

The main role of inert fillers in polymer electrolytes is to enhance ionic conductivity. However, lithium ions in gel polymer electrolytes (GPEs) conduct in liquid solvent rather than along the polymer chains. So far, the main role of inert fillers in improving the electrochemical performance of GPEs is still unclear. Here, various low-cost and common inert fillers (Al2O3, SiO2, TiO2, ZrO2) are introduced into GPEs to study their effects on Li-ion polymer batteries. It is found that the addition of inert fillers has different effects on ionic conductivity, mechanical strength, thermal stability, and, dominantly, interfacial properties. Compared with other gel electrolytes containing SiO2, TiO2, or ZrO2 fillers, those with Al2O3 fillers exhibit the most favorable performance. The high performance is ascribed to the interaction between the surface functional groups of Al2O3 and LiNi0.8Co0.1Mn0.1O2, which alleviates the decomposition of the organic solvent by the cathode, resulting in the formation of a high-quality Li+ conductor interfacial layer. This study provides an important reference for the selection of fillers in GPEs, surface modification of separators, and cathode surface coating.

4.
Nanomicro Lett ; 14(1): 220, 2022 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-36367591

RESUMO

The low immunogenicity of tumors remains one of the major limitations of cancer immunotherapy. Herein, we report a bacterial metabolism-initiated and photothermal-enhanced nanocatalytic therapy strategy to completely eradicate primary tumor by triggering highly effective antitumor immune responses. Briefly, a microbiotic nanomedicine, designated as Cu2O@ΔSt, has been constructed by conjugating PEGylated Cu2O nanoparticles on the surface of an engineered Salmonella typhimurium strain (ΔSt). Owing to the natural hypoxia tropism of ΔSt, Cu2O@ΔSt could selectively colonize hypoxic solid tumors, thus minimizing the adverse effects of the bacteria on normal tissues. Upon bacterial metabolism within the tumor, Cu2O@ΔSt generates H2S gas and other acidic substances in the tumor microenvironment (TME), which will in situ trigger the sulfidation of Cu2O to form CuS facilitating tumor-specific photothermal therapy (PTT) under local NIR laser irradiation on the one hand. Meanwhile, the dissolved Cu+ ions from Cu2O into the acidified TME enables the nanocatalytic tumor therapy by catalyzing the Fenton-like reaction of decomposing endogenous H2O2 into cytotoxic hydroxyl radicals (·OH) on the other hand. Such a bacterial metabolism-triggered PTT-enhanced nanocatalytic treatment could effectively destroy tumor cells and induce a massive release of tumor antigens and damage-associated molecular patterns, thereby sensitizing tumors to checkpoint blockade (ICB) therapy. The combined nanocatalytic and ICB therapy results in the much-inhibited growth of distant and metastatic tumors, and more importantly, induces a powerful immunological memory effect after the primary tumor ablation.

5.
Small ; 18(48): e2204443, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36257819

RESUMO

Earth-abundant tungsten carbide exhibits potential hydrogen evolution reaction (HER) catalytic activity owing to its Pt-like d-band electronic structure, which, unfortunately, suffers from the relatively strong tungsten-hydrogen binding, deteriorating its HER performance. Herein, a catalyst design concept of incorporating late transition metal into early transition metal carbide is proposed for regulating the metal-H bonding strength and largely enhancing the HER performance, which is employed to synthesize CoW bi-metallic carbide Co6 W6 C by a "disassembly-assembly" approach in a confined environment. Such synthesized Co6 W6 C nanocatalyst features the optimal Gibbs free energy of *H intermediate and dissociation barrier energy of H2 O molecules as well by taking advantage of the electron complementary effect between Co and W species, which endows the electrocatalyst with excellent HER performance in both alkaline and seawater/alkaline electrolytes featuring especially low overpotentials, elevated current densities, and much-enhanced operation durability in comparison to commercial Pt/C catalyst. Moreover, a proof-of-concept Mg/seawater battery equipped with Co6 W6 C-2-600 as cathode offers a peak power density of 9.1 mW cm-2 and an open-circuit voltage of ≈1.71 V, concurrently realizing hydrogen production and electricity output.

6.
ACS Appl Mater Interfaces ; 14(39): 44377-44388, 2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36153976

RESUMO

Long-chain n-alkane hydroisomerization reaction plays a vital role in petrochemical and coal chemical industries, which could produce high-quality hydrocarbon fuels and lubricant base oils for modern transportation and mechanical drive. However, minimizing precious metal usage while maintaining the catalyst performance remains a great challenge. Herein, a novel bifunctional catalyst toward n-alkane hydroisomerization reactions, Pt-Al2O3/SAPO-11 (Pt-A/S11) featuring nanoscale separated metal-acid active centers has been synthesized via a simple two-step procedure. In detail, Pt species was first loaded on the nanometer-sized alumina matrices through an incipient wetness impregnation method and then mixed with SAPO-11 molecular sieve to form the composite catalyst. Importantly, 0.015Pt-A/S11 catalyst with the ever-reported lowest Pt loading amount of 0.015 wt % exhibits an extraordinarily high isomer yield of 85.8% compared to previous published results and the traditional Pt-SAPO-11/Al2O3 (Pt-S11/A) catalyst accompanying with the direct contact between metal and acid sites (65.6%). It has been confirmed that the Pt species in 0.015Pt-A/S11 samples exist in single-atom form, leading to an excellent hydroisomerization performance. The possible reaction processes have been discussed to elucidate the exemplary catalytic performance of the synthesized Pt-A/S11 catalysts with nanoscale intimacy of metal-acid sites.

7.
Adv Healthc Mater ; 11(17): e2200031, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35678310

RESUMO

Developing efficient and highly sensitive diagnostic techniques for early detections of pathogenic viruses such as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is vitally important for preventing its widespread. However, the conventional polymerase chain reaction (PCR)-based detection features high complexity, excessive time-consumption, and labor-intensiveness, while viral protein-based detections suffer from moderate sensitivity and specificity. Here, a non-PCR but ultrasensitive viral RNA detection strategy is reported based on a facile nanoprobe-coupling strategy without enzymatic amplification, wherein PCR-induced bias and other shortcomings are successfully circumvented. This approach endows the viral RNA detection with ultra-low background to maximum signal ratio in the linear signal amplification by using Au nanoparticles as reporters. The present strategy exhibits 100% specificity toward SARS-CoV-2 N gene, and ultrasensitive detection of as low as 52 cp mL-1 of SARS-CoV-2 N gene without pre-PCR amplification. This approach presents a novel ultrasensitive tool for viral RNA detections for fighting against COVID-19 and other types of pathogenic virus-caused diseases.


Assuntos
COVID-19 , Nanopartículas Metálicas , COVID-19/diagnóstico , Teste para COVID-19 , Ouro , Humanos , Técnicas de Amplificação de Ácido Nucleico/métodos , Reação em Cadeia da Polimerase , RNA Viral/genética , SARS-CoV-2/genética , Sensibilidade e Especificidade
8.
Nat Commun ; 13(1): 1988, 2022 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-35418125

RESUMO

Constructing nanomaterials mimicking the coordination environments of natural enzymes may achieve biomimetic catalysis. Here we construct a two-dimensional (2D) metal-organic framework (MOF) nanosheet catalyst as an artificial antioxidase for nanocatalytic rheumatoid arthritis treatment. The 2D MOF periodically assembles numbers of manganese porphyrin molecules, which has a metal coordination geometry analogous to those of two typical antioxidases, human mitochondrial manganese superoxide dismutase (Mn-SOD) and human erythrocyte catalase. The zinc atoms of the 2D MOF regulate the metal-centered redox potential of coordinated manganese porphyrin ligand, endowing the nanosheet with both SOD- and catalase-like activities. Cellular experiments show unique anti-inflammatory and pro-biomineralization performances of the 2D MOF, while in vivo animal model further demonstrates its desirable antiarthritic efficacy. It is expected that such a nanocatalytic antioxidation concept may provide feasible approaches to future anti-inflammatory treatments.


Assuntos
Artrite Reumatoide , Estruturas Metalorgânicas , Porfirinas , Animais , Artrite Reumatoide/tratamento farmacológico , Biocatálise , Catalase , Íons , Manganês , Superóxido Dismutase
9.
Sci Adv ; 8(14): eabl9088, 2022 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-35385309

RESUMO

The devil's staircase, describing step-like function for two competing frequencies, is well known over a wide range of dynamic systems including Huyghens' clocks, Josephson junction, and chemical reaction. In condensed matter physics, the devil's staircase has been observed in spatially modulated structures, such as magnetic ordering. It draws widespread attentions because it plays a crucial role in the fascinating phenomena including phase-locking behaviors, commensurate-incommensurate phase transition, and spin-valve effect. Here, we report the observation of polymorphic phase transitions consisting of several steps in PbZrO3-based system-namely, electric devil's staircase-originated from competing ferroelectric and antiferroelectric interactions. We fully characterize a specific electric dipole configuration by decomposing this competitive interaction in terms of basic structure and modulation function. Of particular interest is that the occurrence of many degenerate electric dipole configurations in devil's staircase enables superior energy storage performance. These observations are of great significance for exploring more substantive magnetic-electric correspondence and engineering practical high-power antiferroelectric capacitors.

10.
Nat Commun ; 13(1): 1390, 2022 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35296672

RESUMO

Phase boundary provides a fertile ground for exploring emergent phenomena and understanding order parameters couplings in condensed-matter physics. In Pb(Zr1-xTix)O3, there are two types of composition-dependent phase boundary with both technological and scientific importance, i.e. morphotropic phase boundary (MPB) separating polar regimes into different symmetry and ferroelectric/antiferroelectric (FE/AFE) phase boundary dividing polar and antipolar dipole configurations. In contrast with extensive studies on MPB, FE/AFE phase boundary is far less explored. Here, we apply atomic-scale imaging and Rietveld refinement to directly demonstrate the intermediate phase at FE/AFE phase boundary exhibits a rare multipolar Pb-cations ordering, i.e. coexistence of antipolar or polar displacement, which manifests itself in both periodically gradient lattice spacing and anomalous initial hysteresis loop. In-situ electron/neutron diffraction reveals that the same parent intermediate phase can transform into either FE or AFE state depending on suppression of antipolar or polar displacement, coupling with the evolution of long-/short-range oxygen octahedra tilts. First-principle calculations further show that the transition between AFE and FE phase can occur in a low-energy pathway via the intermediate phase. These findings enrich the structural understanding of FE/AFE phase boundary in perovskite oxides.

11.
Angew Chem Int Ed Engl ; 61(17): e202200480, 2022 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-35143118

RESUMO

Fenton reactions have been recently applied in tumor catalytic therapy, whose efficacy suffers from the unsatisfactory reaction kinetics of Fe3+ to Fe2+ conversion. Here we introduce a co-catalytic concept in tumor catalytic therapy by using a two-dimensional molybdenum disulfide (MoS2 ) nanosheet atomically dispersed with Fe species. The single-atom Fe species act as active sites for triggering Fenton reactions, while the abundant sulfur vacancies generated on the nanosheet favor electron capture by hydrogen peroxide for promoting hydroxyl radical production. Moreover, the 2D MoS2 support also acts as a co-catalyst to accelerate the conversion of Fe3+ to Fe2+ by the oxidation of active Mo4+ sites to Mo6+ , thereby promoting the whole catalytic process. The 2D nanocatalyst exhibits a desirable catalytic performance, as well as a significantly enhanced anticancer efficacy both in vitro and in vivo, which indicates the feasibility for applying such a co-catalytic concept in tumor therapy.


Assuntos
Molibdênio , Neoplasias , Catálise , Humanos , Peróxido de Hidrogênio/química , Neoplasias/tratamento farmacológico , Oxirredução
12.
Angew Chem Int Ed Engl ; 61(15): e202116290, 2022 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-35075773

RESUMO

Fe-N-C electrocatalysts have been demonstrated to be the most promising substitutes for benchmark Pt/C catalysts for the oxygen reduction reaction (ORR). Herein, we report that N-doped carbon materials with trace amounts of iron (0-0.08 wt. %) show excellent ORR activity and durability comparable and even superior to those of Pt/C in both alkaline and acidic media without significant contribution by the metal sites. Such an N-doped carbon (denoted as N-HPCs) features a hollow and hierarchically porous architecture, and more importantly, a noncovalently bonded N-deficient/N-rich heterostructure providing the active sites for oxygen adsorption and activation owing to the efficient electron transfer between the layers. The primary Zn-air battery using N-HPCs as the cathode delivers a much higher power density of 158 mW cm-2 , and the maximum power density in the H2 -O2 fuel cell reaches 486 mW cm-2 , which is comparable to and even better than those using conventional Fe-N-C catalysts at cathodes.

13.
J Am Chem Soc ; 144(1): 314-330, 2022 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-34881869

RESUMO

Mimicking the coordination geometry of the active metal sites of natural enzymes is an efficient strategy in designing therapeutic chemicals with enzymelike in vivo reaction thermodynamics and kinetics. In this study, this chemical concept has been applied for the in situ synthesis of natural antioxidase mimics for catalytic anti-inflammatory treatment by using rheumatoid arthritis, a common and hardly curable immune-mediated diseases, as an example. Briefly, a composite nanomedicine has been first constructed by loading cationic porphyrin ligands into a manganese-engineered mesoporous silica nanocarrier, which can respond to a mildly acidic environment to concurrently release manganous ions and porphyrin ligands, enabling their subsequent coordination and synthesis of manganese porphyrin with a coordination environment of an active Mn site similar to those of the metal sites in natural superoxide dismutase (SOD) and catalase. Due to the strong metal-ligand exchange coupling enabled by the N-ethylpyridinium-2-yl groups tetrasubstituted in the meso positions of N4-macroheterocycles, such a manganese porphyrin presents the SOD-like activity of disproportionating superoxide anions via outer-sphere proton-coupled one-electron transfer (diaquamanganese(III)/monoaquamanganese(II) cycling), as well as the catalase-like activity of disproportionating hydrogen peroxide via inner-sphere proton-coupled two-electron transfer (diaquamanganese(III)/dioxomanganese(V) cycling). Cellular experiments demonstrated the high antioxidative efficacy of the composite nanomedicine in M1 macrophages by promoting their polarization shift to the anti-inflammatory M2 phenotype. Equally importantly, the silicon-containing oligomers released from the manganese silicate nanocarrier can act as heterogeneous nucleation centers of hydroxyapatite for facilitating biomineralization by bone mesenchymal stem cells. Finally, an in vivo adjuvant-induced arthritis animal model further reveals the high efficacy of the nanomedicine in treating rheumatoid arthritis.


Assuntos
Metaloporfirinas
14.
Small ; 17(42): e2102113, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34524730

RESUMO

Photodynamic therapy (PDT) has attracted tremendous attention due to its advantages such as high safety and effectiveness compared to traditional radiotherapy and chemotherapy. However, the intratumoral hypoxic microenvironment will inevitably compromise the PDT effect of the highly oxygen-dependent type II photosensitizers, implicating the urgent demand for continuous intratumoral oxygenation. Herein, biocompatible photosynthetic cyanobacteria have been modified with inorganic two-dimensional black phosphorus nanosheets (BPNSs) to be a novel bioreactor termed as Cyan@BPNSs. Upon 660 nm laser irradiation, the photosynthetic cyanobacteria generate oxygen continuously in situ through photosynthesis, followed by the photosensitization of BPNSs for activating oxygen into singlet oxygen (1 O2 ), resulting in a large amount of 1 O2 accumulation at the tumor site and the consequent strong tumor cell killing effect both in vitro and in vivo. This work provides an attractive strategy for efficient and biocompatible PDT, meanwhile extends the scope of microbiotic nanomedicine by hybridizing microorganisms with inorganic nanophotosensitizer.


Assuntos
Cianobactérias , Fotoquimioterapia , Linhagem Celular Tumoral , Fósforo , Fármacos Fotossensibilizantes/uso terapêutico , Fotossíntese
15.
Research (Wash D C) ; 2021: 9769867, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34195614

RESUMO

The therapeutic outcomes of noninvasive sonodynamic therapy (SDT) are always compromised by tumor hypoxia, as well as inherent protective mechanisms of tumor. Herein, we report a simple cascade enzymatic approach of the concurrent glucose depletion and intratumoral oxygenation for starvation-sensitized and oxygenation-amplified sonodynamic therapy using a dual enzyme and sonosensitizer-loaded nanomedicine designated as GOD/CAT@ZPF-Lips. In particular, glucose oxidase- (GOD-) catalyzed glycolysis would cut off glucose supply within the tumor, resulting in the production of tumor hydrogen peroxide (H2O2) while causing tumor cells starvation. The generated H2O2 could subsequently be decomposed by catalase (CAT) to generate oxygen, which acts as reactants for the abundant singlet oxygen (1O2) production by loaded sonosensitizer hematoporphyrin monomethyl ether (HMME) upon the US irradiation, performing largely elevated therapeutic outcomes of SDT. In the meantime, the severe energy deprivation enabled by GOD-catalyzed glucose depletion would prevent tumor cells from executing protective mechanisms to defend themselves and make the tumor cells sensitized and succumbed to the cytotoxicity of 1O2. Eventually, GOD/CAT@ZPF-Lips demonstrate the excellent tumoral therapeutic effect of SDT in vivo without significant side effect through the cascade enzymatic starvation and oxygenation, and encouragingly, the tumor xenografts have been found completely eradicated in around 4 days by the intravenous injection of the nanomedicine without reoccurrence for as long as 20 days.

16.
Nat Commun ; 12(1): 3393, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34099712

RESUMO

The iron gall ink-triggered chemical corrosion of hand-written documents is a big threat to Western cultural heritages, which was demonstrated to result from the iron gall (GA-Fe) chelate-promoted reactive oxygen species generation. Such a phenomenon has inspired us to apply the pro-oxidative mechanism of GA-Fe to anticancer therapy. In this work, we construct a composite cancer nanomedicine by loading gallate into a Fe-engineered mesoporous silica nanocarrier, which can degrade in acidic tumor to release the doped Fe3+ and the loaded gallate, forming GA-Fe nanocomplex in situ. The nanocomplex with a highly reductive ligand field can promote oxygen reduction reactions generating hydrogen peroxide. Moreover, the resultant two-electron oxidation form of GA-Fe is an excellent Fenton-like agent that can catalyze hydrogen peroxide decomposition into hydroxyl radical, finally triggering severe oxidative damage to tumors. Such a therapeutic approach by intratumoral synthesis of GA-Fe nano-metalchelate may be instructive to future anticancer researches.


Assuntos
Antineoplásicos/administração & dosagem , Ácido Gálico/administração & dosagem , Ferro/administração & dosagem , Nanopartículas Metálicas/administração & dosagem , Neoplasias/tratamento farmacológico , Animais , Antineoplásicos/química , Antineoplásicos/metabolismo , Catálise , Complexos de Coordenação/administração & dosagem , Complexos de Coordenação/química , Complexos de Coordenação/metabolismo , Portadores de Fármacos/química , Feminino , Ácido Gálico/química , Ácido Gálico/metabolismo , Células HeLa , Células Endoteliais da Veia Umbilical Humana , Humanos , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio , Radical Hidroxila/química , Radical Hidroxila/metabolismo , Injeções Intravenosas , Ferro/química , Ferro/metabolismo , Ligantes , Nanopartículas Metálicas/química , Camundongos , Neoplasias/patologia , Oxirredução , Oxigênio/metabolismo , Dióxido de Silício/química , Ensaios Antitumorais Modelo de Xenoenxerto
17.
ChemSusChem ; 14(10): 2247-2254, 2021 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-33783971

RESUMO

The electroreduction of CO2 into the highly value-added fuel formic acid (HCOOH) has been considered an ideal approach to convert renewable energy and mitigate environmental crisis. SnO2 electrode is one of the promising candidates to electrocatalytically convert CO2 to HCOOH, but its poor stability limits its future development and application. In this study, highly stable SnO2 /Bi2 O3 oxide catalysts are obtained by distributing SnO2 nanoparticles on the surface of Bi2 O3 sheets. The XPS spectra revealed an interfacial electronic transportation from Bi2 O3 sheets to SnO2 nanoparticles, which made SnO2 rich of electrons. The strong interfacial interaction protected the active sites of SnO2 from self-reduction in CO2 electroreduction reaction (CO2 RR), stabilizing SnO2 species in the composite catalyst even after long-term usage. Calculations based on density functional theory signified that the presence of Bi2 O3 favored the adsorption of HCOO* intermediate, improved the CO2 conversion into HCOOH on SnO2 /Bi2 O3 interface. As a result, the SnO2 /Bi2 O3 catalyst attained high performance on CO2 RR (the highest FE C 1 value of 90 % at -1.0 V vs. RHE), suppressing H2 evolution reaction (HER) at high potentials. In particular, the selectivity of HCOOH remained above 76 % in a wide potential window (from -1.0 to -1.4 V vs. RHE) and a long duration (12 h).

18.
J Hazard Mater ; 403: 124019, 2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33265045

RESUMO

Photocatalytic CO2 reduction into fuels has been an attractive research topic. Herein, Ag and TiO2 nanoparticles co-loaded zeolite TS-1 (Ag-TiO2/TS-1) were synthesized by the ion-exchange and subsequently in-situ photodeposition method. The obtained Ag-TiO2/TS-1 sample has a high surface area and rich Ti3+-Vo defects and as well as highly dispersed Ag nanoparticles. As expected, the sample Ag-TiO2/TS-1 not only shows high CO2 adsorption capacity, but also improves the separation efficiency of photogenerated electron-hole pairs. As a result, only CO and CH4 can be detected on the sample Ag-TiO2/TS-1 in the photocatalytic CO2 conversion, and the competing H2 evolution can be completely suppressed, suggestive of its high selectivity. The super photocatalytic activity toward CO2 reduction can be ascribed to the synergistic effect among highly dispersed Ag nanoparticle, the support zeolite TS-1 and TiO2 with highly exposed {101} planes.

19.
ChemSusChem ; 13(22): 5896-5900, 2020 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-32940407

RESUMO

Converting CO2 into value-added chemicals or fuels by electrochemical CO2 reduction reaction (CO2 RR) has aroused great interest, whereas designing highly active and selective electrocatalysts is still a challenge. Herein, a novel kind of electrochemical catalyst composed with SnO2 and organic carbon (OC), named as SnO2 /OC, was facilely constructed for CO2 RR. The obtained SnO2 /OC exhibits both high faradaic efficiency for formate (∼75 %) and carbon products (∼95 %) as well as excellent stability. High surface area with hierarchically porous structure and the homogeneous formation of Sn-O-C linkages in SnO2 /OC jointly promote the adsorption and activation of CO2 , as well as fast transport of reactants and products.

20.
Adv Mater ; 32(36): e2002246, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32705751

RESUMO

The oxidation of intracellular biomolecules by reactive oxygen species (ROS) forms the basis for ROS-based tumor therapy. However, the current therapeutic modalities cannot catalyze H2 O2 and O2 concurrently for ROS generation, thereby leading to unsatisfactory therapeutic efficacy. Herein, it is reported a bioinspired hollow N-doped carbon sphere doped with a single-atom copper species (Cu-HNCS) that can directly catalyze the decomposition of both oxygen and hydrogen peroxide to ROS, namely superoxide ion (O2 •- ) and the hydroxyl radical (•OH), respectively, in an acidic tumor microenvironment for the oxidation of intracellular biomolecules without external energy input, thus resulting in an enhanced tumor growth inhibitory effect. Notably, the Fenton reaction turnover frequency of Cu species in Cu-HNCS is ≈5000 times higher than that of Fe in commercial Fe3 O4 nanoparticles. Experimental results and density functional theory calculations reveal that the high catalytic activity of Cu-HNCS originates from the single-atom copper, and the calculation predicts a next-generation Fenton catalyst. This work provides an effective paradigm of tumor parallel catalytic therapy for considerably enhanced therapeutic efficacy.


Assuntos
Materiais Biomiméticos/química , Cobre/química , Materiais Biomiméticos/uso terapêutico , Catálise , Linhagem Celular Tumoral , Teoria da Densidade Funcional , Humanos , Peróxido de Hidrogênio/metabolismo , Modelos Moleculares , Conformação Molecular , Oxirredução
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