RESUMO
Aerobically autoxidized self-charging concept has drawn significant attraction due to its promising chemical charge features without external power supply. Particularly, heteroatom-doped carbon materials with abundant oxidizable sites and good conductivity are expected to be ideal cathode materials. However, there is no well-defined aerobically autoxidized self-charging concept based on heteroatom-doped carbon materials, significantly hindering the design of related carbon cathodes. An aerobically autoxidized self-chargeable concept derived from synergistic effect of pyrrolic nitrogen and catechol configuration in carbon cathode using model single pyrrolic nitrogen and oxygen (N-5, O) co-doped carbon and O-enriched carbon is proposed. First, self-charging of N-5, O co-doped carbon cathode can be achieved by aerobic oxidation of pyrrolic nitrogen and catechol to oxidized pyrrolic nitrogen and ortho-quinone configurations, respectively. Second, introducing a single pyrrolic nitrogen configuration enhanced acidic wettability of N-5, O co-doped carbon facilitating air self-charge/galvanic discharge involving proton removal/introduction. Third, synergistic effect of pyrrolic nitrogen and hydroxyl species with the strong electron-donating ability to conjugated carbon-based backbone endows N-5, O co-doped carbon with a higher highest occupied molecular orbital (HOMO) energy level more susceptible to oxidation charging. The assembled Cu/Carbon batteries can drive a timer after every air-charging run. This promising aerobically autoxidized self-charging concept can inspire exploring high-efficiency self-charging devices.
RESUMO
This study explores the mechanisms enhancing phosphorus (P) release from sludge in anaerobic digestion (AD) with thermal hydrolysis pretreatment (THP) using sequential chemical extraction, X-ray absorption near-edge structure spectroscopy (XANES), 31P NMR, and multiomics. THP-treated sludge notably increased liquid-phase P by 53.8% over 3 days compared to sewage sludge (SS), identifying solid-phase Fe-P as the primary P source. The THP+AD also provided a higher abundance of bacteria that contributed to P release through multiple pathways (MPRPB), whereas SS+AD enriched some microbial species with single P release pathway. Moreover, species co-occurrence network analysis underlined the pivotal role of P-releasing bacteria in THP+AD, with 8 out of 16 keystones being P-releasers. Among the 63 screened genes that were related to P transformations and release, the poly beta-hydroxybutyrate (PHB) synthesis genes associated with polyphosphate bacteria-mediated P release were more abundant in THP+AD than in SS+AD. Furthermore, the upregulation of genes involved in methyl phosphonate metabolism in the THP-treated sludge enhanced the methane production potential of the AD process. These findings suggested that MPRPB were indeed the main contributors to P release, and enrichment in the THP+AD process enhanced their capability for P liberation.
Assuntos
Fósforo , Esgotos , Fósforo/metabolismo , Esgotos/microbiologia , Anaerobiose , HidróliseRESUMO
Zinc oxide nanoparticles (ZnO NPs) expedite the conversion of organic phosphorus (OP) into PO4-P (Pi), facilitating phosphorus (P) absorption by algae. Our study explored the mechanisms of converting OP (2-aminoethylphosphonic acid (AEP) and ß-glycerol phosphate (ß-GP)) into Pi in Chlorella pyrenoidosa under P deficiency with sunscreen and ZnO NPs. Cell density followed the order of K2HPO4 > ß-GP+ZnO > ß-GP > AEP+ZnO > AEP > P-free. ZnO NPs promoted the conversion of ß-GP, containing C-O-P bonds (0.028-0.041 mg/L), into Pi more efficiently than AEP, which possesses C-P bonds (0.022-0.037 mg/L). Transcriptomics revealed Pi transport/metabolism (phoB (3.99-12.01 fold), phoR (2.20-5.50 fold), ppa (4.49-10.40 fold), and ppk (2.50-5.40 fold)) and phospholipid metabolism (SQD1 (1.85-2.79 fold), SQD2 (2.60-6.53 fold), MGD (2.13-3.21 fold), and DGD (4.08-7.56 fold)) were up-regulated compared to K2HPO4. 31P nuclear magnetic resonance spectroscopy identified intracellular P as polyphosphate, orthophosphate, and pyrophosphate. Synchrotron radiation-based X-ray near-edge structure spectroscopy indicated that K2HPO4 and Zn3(PO4)2 in ß-GP+ZnO were increased by 8.09% and 7.28% compared to AEP+ZnO, suggesting superior P storage in ß-GP+ZnO. Overall, ZnO NPs improved photoinduced electron-hole pair separation and charge separation efficiency and amplified the ·OH and ·O2- levels, promoting OP photoconversion into Pi and algae growth.
Assuntos
Chlorella , Nanopartículas , Fósforo , Protetores Solares , Óxido de Zinco , Óxido de Zinco/química , Óxido de Zinco/farmacologia , Chlorella/metabolismo , Nanopartículas/químicaRESUMO
Recently, single-atom catalysts are attracting much attention in sensor field due to their remarkable peroxidase- or oxidase-like activities. Herein, peroxidase-like FeCoZn triple-atom catalyst supported on S- and N-doped carbon derived from ZIF-8 (FeCoZn-TAC/SNC) serves as a proof-of-concept nanozyme. In this paper, a dual-channel nanozyme-based colorimetric sensor array is presented for identifying seven preservatives in food. Further experiments reveal that the peroxidase-like activity of the FeCoZn TAzyme enables it to catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) and o-phenylenediamine (OPD) in the presence of H2 O2 , yielding the blue oxTMB and yellow oxOPD, respectively. However, food preservatives are adsorbed on the nanozyme surface through π-π stacking interaction and hydrogen bond, and the reduction in catalytic activity of FeCoZn TAzyme causes differential colorimetric signal variations, which provide unique "fingerprints" for each food preservative.
Assuntos
Conservantes de Alimentos , Peroxidase , Colorimetria , Nariz Eletrônico , Oxirredutases , Peroxidases , Corantes , Peróxido de HidrogênioRESUMO
The preparation of TiO2 and metal-organic framework (MOF) into composite photocatalysts has been proven to be a mature and effective strategy to achieve stronger catalytic activity. In this work, we focus on exploring the significant effects and mechanisms of the relative positions of decorated titanium oxide nanoparticles and MOFs on the final catalytic activity. We first used a simple in situ method to encapsulate tiny TiO2 nanoparticles into a Zr-MOF (PCN-222), where Zr-Ti bonds were created at the interface of the two components. Thanks to the strong interfacial interaction forces, band bending occurred in TiO2@PCN-222 and a more negative conduction band (Δ = 0.26 V) with better electron transport properties was obtained. The results of photocatalytic CO2 reduction experiments under visible light showed a 78% increase (142 µmol g-1 h-1) in the production rate of HCOO-. Surprisingly, the loading of TiO2 nanoparticles on the MOF surface (TiO2@PCN-222) resulted in a significant decrease of 56% in the catalyst yield activity due to poor adsorption and electron transfer properties. This work demonstrates the possibility of tuning the band structure and catalytic activity of MOFs with the help of changing the position of the dopant and shows the importance of the rational design of MOF-based composites.
RESUMO
Zinc oxide nanoparticles (ZnO NPs), as the highly efficient photocatalysts, could enhance the transformation of biogenic organic phosphorus (OP) to orthophosphate (PO43-) by photodegradation, accelerating eutrophication. Conversely, orthophosphate can also transform ZnO NPs and thus potentially alter their catalytic and chemical properties. Here, we investigated the transformation mechanisms of three biogenic OP compounds and ZnO NPs under ultraviolet light (UV) illumination: inositol phosphates (IHPs), nucleic acids (DNA), and aminoethylphosphonic acid (AEP). The physicochemical characteristics of the resulting products were systematically characterized. Results show that ZnO NPs accelerated the transformation of IHPs, DNA, and AEP to inorganic phosphorus with the direct photolysis efficiencies of 98.14, 87.68, and 51.76%, respectively. The main component of the precipitates remained ZnO NPs, and Zn3(PO4)2 was identified. Zinc phytate was determined in the ZnO NP-IHP system. 31P NMR and FTIR further confirmed that the aquatic phase contained orthophosphate. Photoproduced hydroxyl (·OH) and superoxide (·O2-) were proved to play a dominant role in the OP photomineralization. Furthermore, ZnO NPs significantly enhanced the intensity of ·OH and ·O2- compared to the OP and Zn2+ solution alone. This work explored the light-induced mineralization processes of OP with ZnO NPs indicating that nanophotocatalysts may play a positive role in transformation of OP species in aquatic environments to further contribute to eutrophication.
Assuntos
Nanopartículas Metálicas , Nanopartículas , Óxido de Zinco , Fósforo/química , Nanopartículas/química , Fosfatos , ZincoRESUMO
Ruthenium-based materials are considered great promising candidates to replace Pt-based catalysts for hydrogen production in alkaline conditions. Herein, we adopt a facile method to rationally design a neoteric Schottky catalyst in which uniform ultrafine ruthenium nanoparticles featuring lattice compressive stress are supported on nitrogen-modified carbon nanosheets (Ru NPs/NC) for efficient hydrogen evolution reaction (HER). Lattice strain and Schottky junction dual regulation ensures that the Ru NPs/NC catalyst with an appropriate nitrogen content displays superb H2 evolution in alkaline media. Particularly, Ru NPs/NC-900 with 1.3% lattice compressive strain displays attractive activity and durability for the HER with a low overpotential of 19 mV at 10 mA cm-2 in 1.0 M KOH electrolyte. The in situ X-ray absorption fine structure measurements indicate that the low-valence Ru nanoparticle with shrinking Ru-Ru bond acts as catalytic active site during the HER process. Furthermore, multiple spectroscopy analysis and density functional theory calculations demonstrate that the lattice strain and Schottky junction dual regulation tunes the electron density and hydrogen adsorption of the active center, thus enhancing the HER activity. This strategy provides a novel concept for the design of advanced electrocatalysts for H2 production.
RESUMO
Natural enzymes are efficient and versatile biocatalysts but suffer in their environmental tolerance and catalytic stability. As artificial enzymes, nanozymes can improve the catalytic stability, but it is still a challenge to achieve high catalytic activity. Here, we employed atomic engineering to build the artificial enzyme named Au24Ag1 clusterzyme that hosts an ultrahigh catalytic activity as well as strong physiological stability via atom manipulation. The designed Au24Ag1 clusterzyme activates the Ag-S active site via lattice expansion in the oligomer atom layer, showing an antioxidant property 72 times higher than that of natural antioxidant Trolox. Enzyme-mimicked studies find that Au24Ag1 clusterzyme exhibits high catalase-like (CAT-like) and glutathione peroxidase-like (GPx-like) activity with a maximum reaction rate of 68.9 and 17.8 µM/min, respectively. Meanwhile, the unique catalytic landscape exhibits distinctive reactions against inflammation by inhibiting the cytokines at an early stage in the brain. Atomic engineering of clusterzymes provides a powerful and attractive platform with satisfactory atomic dispersion for tailoring biocatalysts freely at the atomic level.
Assuntos
Catálise , Catalase/genéticaRESUMO
A zinc-based single-atom catalyst has been recently explored with distinguished stability, of which the fully occupied Zn2+ 3d10 electronic configuration is Fenton-reaction-inactive, but the catalytic activity is thus inferior. Herein, we report an approach to manipulate the s-band by constructing a B,N co-coordinated Zn-B/N-C catalyst. We confirm both experimentally and theoretically that the unique N2 -Zn-B2 configuration is crucial, in which Zn+ (3d10 4s1 ) can hold enough delocalized electrons to generate suitable binding strength for key reaction intermediates and promote the charge transfer between catalytic surface and ORR reactants. This exclusive effect is not found in the other transition-metal counterparts such as M-B/N-C (M=Mn, Fe, Co, Ni and Cu). Consequently, the as-obtained catalyst demonstrates impressive ORR activity, along with remarkable long-term stability in both alkaline and acid media. This work presents a new concept in the further design of electrocatalyst.
RESUMO
In the original article, few equations and units were published incorrectly.
RESUMO
Protein-bound calcium (prCa) constitutes about 40% of serum total calcium, in which albumin is the most dominant protein. Given the chemical interaction between calcium and phosphate (Pi), the increased serum Pi in chronic kidney disease may cause changes in the composition and structure of the prCa fraction. Here, we report the phosphate binding on the protein-bound calcium in uremic rat serum. Using adenine-fed rats as a uremic model, we separated the calcium and phosphate fractions in rat serum by ultrafiltration, and found that the level of protein-bound phosphate (prPi) in the uremic serum was markedly higher than in control. The elevated prPi level was comparable to the prCa level, consistent with the presence of protein-bound calcium phosphate pr(Ca)j-m(CaPi)m. We then confirmed its presence by ex vivo X-ray absorption near-edge structure spectroscopy, revealing the discrete state of the calcium phosphate clusters associated with protein. Finally, in a quantitative investigation using Ca- and Pi-boosted serum, we discovered the threshold concentration for the Pi binding on prCa, and determined the binding constant. The threshold, while preventing Pi from binding to prCa in normal condition, allows the reaction to take place in hyperphosphatemia conditions. The protein-bound calcium phosphate could act as a link between the metabolism of serum proteins and the homeostasis of phosphate and calcium, and it deserves further investigation whether the molar ratio of (prPi/prCa)â 100% may serve as a serum index of the vascular calcification status in chronic kidney disease.
Assuntos
Proteínas Sanguíneas/metabolismo , Fosfatos de Cálcio/metabolismo , Uremia/metabolismo , Animais , Homeostase , Ligação Proteica , RatosRESUMO
In multicellular organisms, receptor tyrosine kinases (RTKs) control a variety of cellular processes, including cell proliferation, differentiation, migration, and survival. Sprouty (SPRY) proteins represent an important class of ligand-inducible inhibitors of RTK-dependent signaling pathways. Here, we investigated the role of SPRY1 in cells of the central nervous system (CNS). Expression of SPRY1 was substantially higher in neural stem cells than in cortical neurons and was increased during neuronal differentiation of cortical neurons. We found that SPRY1 was a direct target gene of the CNS-specific microRNA, miR-124 and miR-132. In primary cultures of cortical neurons, the neurotrophic factors brain-derived neurotrophic factor (BDNF) and Basic fibroblast growth factor (FGF2) downregulated SPRY1 expression to positively regulate their own functions. In immature cortical neurons and mouse N2 A cells, we found that overexpression of SPRY1 inhibited neurite development, whereas knockdown of SPRY1 expression promoted neurite development. In mature neurons, overexpression of SPRY1 inhibited the prosurvival effects of both BDNF and FGF2 on glutamate-mediated neuronal cell death. SPRY1 was also upregulated upon glutamate treatment in mature neurons and partially contributed to the cytotoxic effect of glutamate. Together, our results indicate that SPRY1 contributes to the regulation of CNS functions by influencing both neuronal differentiation under normal physiological processes and neuronal survival under pathological conditions.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Sobrevivência Celular/fisiologia , Proteínas de Membrana/metabolismo , MicroRNAs/genética , Neurônios/citologia , Animais , Apoptose/fisiologia , Diferenciação Celular/genética , Proliferação de Células/fisiologia , Células Cultivadas , Camundongos Endogâmicos C57BL , MicroRNAs/metabolismo , Fosfoproteínas/metabolismoRESUMO
BACKGROUND: Wilson's disease (WD) is an autosomal recessive disease of impaired copper metabolism. Previous study demonstrated that WD with corpus callosum abnormalities (WD-CCA) was limited to the posterior part (splenium). This study aimed to compare clinical features between WD-CCA and WD without corpus callosum abnormalities (WD-no-CCA). METHODS: Forty-one WD patients who had markedly neurological dysfunctions were included in this study. We retrospectively reviewed clinical, biochemical characteristics and MRI findings in the 41 WD patients. All patients were assessed using the Unified Wilson's Disease Rating Scale. RESULTS: Nine patients had corpus callosum abnormalities, 4 of 9 patients had abnormal signal in the genu and splenium, 5 of 9 patients had abnormal signal only in the splenium. WD-CCA had longer course (9.9 ± 4.0 years vs. 3.4 ± 3.6 years, p<0.01), more severe neurological dysfunctions (37.6 vs. 65.9, p<0.01) and higher psychiatric symptoms scores (11.2 vs. 22.5, p<0.01) than WD-no-CCA. The MRI findings indicated that WD-CCA had higher ratio than WD-no-CCA in globus pallidus (88.9% vs. 43.8%, p = 0.024) and thalamus (100% vs. 59.4%, p = 0.038). The index of liver function and copper metabolism had no significant in WD-CCA and WD-no-CCA patients. CONCLUSION: Our findings indicate Wilson's disease can involve the posterior as well as the anterior part of CC and patients with CC involvement had more extensive brain lesions, more severe neurological dysfunctions and psychiatric symptoms.
Assuntos
Corpo Caloso/patologia , Degeneração Hepatolenticular/patologia , Adulto , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Estudos RetrospectivosRESUMO
Submicron-sized iron oxide particles can influence the activity of bacteria, but the exact mechanisms of oxide toxicity toward bacteria remain elusive. By using atomic force microscopy (AFM), soft X-ray tomography (Nano-CT), and Fourier transform infrared (FTIR) spectrometry, we show how the size-dependent interfacial interactions between hematite particles and bacteria in the absence of any ligands contribute to the antimicrobial properties against Gram-positive and Gram-negative bacterial strains. We found that surface adhesion between hematite particles and bacterial cells is initially dominated by Lifshitz van der Waals and electrostatic forces. Subsequently, the rapid formation of P-O-Fe bonds occurs, followed by changes in the structures of membrane proteins in 2 h, resulting in the loss of the structural integrity of the membrane within 10 h. Thus, particles can migrate into the cells. After contact with bacterial cells, reactive oxygen species are generated on the surface of hematite particles, leading to cell permeabilization. G- bacteria appear to be more susceptible to this process than G+ bacteria because the latter exhibit weaker adhesion forces toward hematite and benefit from the protective effects of the peptidoglycan layers. Our work revealed that hematite nanoparticles are more toxic to bacteria than microscaled particles due to their strong interfacial physicochemical interactions with the cells.
Assuntos
Toxinas Bacterianas , Compostos Férricos , Bactérias Gram-Negativas , Microscopia de Força AtômicaRESUMO
Sb-based nanocomposites are attractive anode materials for batteries as they exhibit large theoretical capacity and impressive working voltage. However, tardy potassium ion diffusion characteristics, unstable Sb/electrolyte interphase, and huge volume variation pose a challenge, hindering their practical use for potassium-ion batteries (PIBs). Now, a simple robust strategy is presented for uniformly impregnating ultrasmall Sb nanocrystals within carbon nanofibers containing an array of hollow nanochannels (denoted u-Sb@CNFs), resolving the issues above and yielding high-performance PIBs. u-Sb@CNFs can be directly employed as an anode, thereby dispensing with the need for conductive additives and binders. Such a judiciously crafted u-Sb@CNF-based anode renders a set of intriguing electrochemical properties, representing large charge capacity, unprecedented cycling stability, and outstanding rate performance. A reversible capacity of 225â mAh g-1 is retained after 2000 cycles at 1â A g-1 .
RESUMO
The single-site catalyst (SSC) characteristic of atomically dispersed active centers will not only maximize the catalytic activity, but also provide a promising platform for establishing the structure-activity relationship. However, arbitrary arrangements of active sites in the existed SSCs make it difficult for mechanism understanding and performance optimization. Now, a well-defined ultrathin SSC is fabricated by assembly of metal-porphyrin molecules, which enables the precise identification of the active sites for d-orbital energy engineering. The activity of as-assembled products for electrocatalytic CO2 reduction is significantly promoted via lifting up the energy level of metal d z 2 orbitals, exhibiting a remarkable Faradaic efficiency of 96 % at the overpotential of 500â mV. Furthermore, a turnover frequency of 4.21â s-1 is achieved with negligible decay over 48â h.
RESUMO
The class IIa histone deacetylases (HDACs) play important roles in the central nervous system during diverse biological processes such as synaptic plasticity, axon regeneration, cell apoptosis, and neural differentiation. Although it is known that HDAC5 regulates neuronal differentiation, neither the physiological function nor the regulation of HDAC5 in neuronal differentiation is clear. Here, we identify HDAC5 as an inhibitor of neurite elongation and show that HDAC5 is regulated by the brain enriched microRNA miR-124 and miR-9. We discover that HDAC5 inhibits neurite extension both in differentiated P19 cells and primary neurons. We also show that the neuronal membrane glycoprotein GPM6A (M6a) is a direct target gene of HDAC5 regulated transcriptional factor MEF2C. HDAC5 inhibits neurite elongation, acting at least partially via a MEF2C/M6a signaling pathway. We also confirmed the miR-124/miR-9 regulated HDAC5-MEF2C-M6a pathway regulates neurite development in primary neurons. Thus, HDAC5 emerges as a cellular conductor of MEF2C and M6a activity and is regulated by miR-124 and miR-9 to control neurite development.
Assuntos
Células-Tronco Embrionárias/enzimologia , Histona Desacetilases/metabolismo , Glicoproteínas de Membrana/metabolismo , MicroRNAs/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Células-Tronco Neurais/enzimologia , Neuritos/enzimologia , Neurogênese , Animais , Regulação para Baixo , Células-Tronco Embrionárias/efeitos dos fármacos , Regulação da Expressão Gênica no Desenvolvimento , Regulação Enzimológica da Expressão Gênica , Idade Gestacional , Células HEK293 , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/genética , Humanos , Fatores de Transcrição MEF2/genética , Fatores de Transcrição MEF2/metabolismo , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , Proteínas do Tecido Nervoso/genética , Células-Tronco Neurais/efeitos dos fármacos , Neuritos/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Transdução de Sinais , TransfecçãoRESUMO
Nitrogen-doped carbons with promising electrochemical performance exhibit a strong dependence on nitrogen configuration. Therefore, accurate control of nitrogen configurations is crucial to clarify their influence. Unfortunately, there is still no well-defined conversion route to finely control nitrogen configuration. Herein, we proposed the concept of 100% conversion from pyridinic to pyrrolic nitrogen in carbon materials through low-temperature pyrolysis and alkali activation of hydroxypyridine-3-halophenol-formaldehyde resins. Their dehalogenation pyrolysis promotes formation of carbon intermediates and conversion of tautomeric pyridone and hydroxypyridine into pyrrolic and pyridinic nitrogen through eliminating carbonyl and hydroxyl functionalities, respectively. Continuous thermal alkali activation introduces hydroxyl groups into carbon materials, converting pyridinic species to intermediate hydroxypyridine and pyridone; subsequently, these configurations transform to pyridinic and pyrrolic nitrogen, respectively, and finally, an excessive alkali ensures 100% conversion from pyridinic to pyrrolic nitrogen. NaOH activation for pyrrolic and pyridinic nitrogen co-doped carbon and KOH activation for model nitrogen-containing compounds including acridine, phenanthridine, and acridone further confirm that alkali activation plays an indispensable role in 100% conversion from pyridinic to pyrrolic units through the tautomeric hydroxypyridine and pyridone intermediates. Low-temperature alkali-induced controllable conversion of nitrogen configuration in carbon materials is suitable modulating nitrogen configurations for almost all nitrogen-doped carbon materials in electrochemical applications.
RESUMO
Implanted neural electrodes have been widely used to treat brain diseases that require high sensitivity and biocompatibility at the tissue-electrode interface. However, currently used clinical electrodes cannot meet both these requirements simultaneously, which hinders the effective recording of electronic signals. Herein, nanozyme-based neural electrodes incorporating bioinspired atomically precise clusters are developed as a general strategy with a heterogeneous design for multiscale and ultrasensitive neural recording via quantum transport and biocatalytic processes. Owing to the dual high-speed electronic and ionic currents at the electrode-tissue interface, the impedance of nanozyme electrodes is 26 times lower than that of state-of-the-art metal electrodes, and the acquisition sensitivity for the local field potential is ≈10 times higher than that of clinical PtIr electrodes, enabling a signal-to-noise ratio (SNR) of up to 14.7 dB for single-neuron recordings in rats. The electrodes provide more than 100-fold higher antioxidant and multi-enzyme-like activities, which effectively decrease 67% of the neuronal injury area by inhibiting glial proliferation and allowing sensitive and stable neural recording. Moreover, nanozyme electrodes can considerably improve the SNR of seizures in acute epileptic rats and are expected to achieve precise localization of seizure foci in clinical settings.
Assuntos
Neurônios , Ratos , Animais , Eletrodos , Eletrodos Implantados , Razão Sinal-Ruído , Neurônios/fisiologia , Impedância Elétrica , MicroeletrodosRESUMO
Conversion of plastic wastes to valuable carbon resources without using noble metal catalysts or external hydrogen remains a challenging task. Here we report a layered self-pillared zeolite that enables the conversion of polyethylene to gasoline with a remarkable selectivity of 99% and yields of >80% in 4 h at 240 °C. The liquid product is primarily composed of branched alkanes (selectivity of 72%), affording a high research octane number of 88.0 that is comparable to commercial gasoline (86.6). In situ inelastic neutron scattering, small-angle neutron scattering, solid-state nuclear magnetic resonance, X-ray absorption spectroscopy and isotope-labelling experiments reveal that the activation of polyethylene is promoted by the open framework tri-coordinated Al sites of the zeolite, followed by ß-scission and isomerization on Brönsted acids sites, accompanied by hydride transfer over open framework tri-coordinated Al sites through a self-supplied hydrogen pathway to yield selectivity to branched alkanes. This study shows the potential of layered zeolite materials in enabling the upcycling of plastic wastes.