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1.
Bioresour Technol ; : 126436, 2021 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-34848331

RESUMO

The conversion of cellulose to platform chemicals has attracted much attention because of its renewability. This work proposed an earth-abundant cobalt disulfide as a heterogeneous catalyst for methyl levulinate production from cellulose. The highest yield of methyl levulinate reached 61 mol% under the tested conditions of 200 °C, 2 MPa initial pressure, 0.45 catalyst/cellulose mass ratio, and 3 h reaction time. The XRD and TEM analyses demonstrated the crystal facet (111) of cobalt disulfide as a robust active site, which was in good agreement with the highest acidity of the crystal facet (111) calculated by the work functions. The XPS characterization showed that the main chemical valence of cobalt disulfide responsible for the methyl levulinate production was the surface Co2+ species. This study is valuable for the development of a recoverable catalyst for the cellulose to methyl levulinate process.

2.
Bioresour Technol ; 346: 126582, 2021 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-34953989

RESUMO

Pyrolysis of the middle layer of a surgical mask (MLM) and inner and outer layers of a surgical mask (IOM) was performed to assess their potential valorization as waste-to-energy feedstocks, and the characteristics of the resulting products were investigated. Pyrolysis of the main organics in waste surgical masks occurred at a very narrow temperature range of 456-466 °C. The main product was carbon-rich and oxygen-deficient liquid oil with a high heating value (HHV) of 43.5 MJ/kg. From the life-cycle perspective, environmental benefits and advantages of this upcycling approach were verified compared with conventional waste management approaches. This study advocated the potential application of waste surgical masks as feedstocks for fuels and energy, which is beneficial to mitigate plastic pollution and achieve sustainable plastic waste-to-energy upcycling, simultaneously.

3.
Artigo em Inglês | MEDLINE | ID: mdl-34734406

RESUMO

INTRODUCTION: Long noncoding RNAs are associated with progressions of lung cancer. LINC00839 has been dysregulated in osteosarcoma, breast cancer and lung cancer (LC). As an upregulated lncRNA, the roles of LINC00839 in lung cancer remain unclear. MATERIAL AND METHODS: RNA expressions of LINC00839, miR-519d-3p and JMJD6 were assessed using RT-qPCR and JMJD6 protein expressions were analyzed through Western blot. Meanwhile, viabilities of A549 and H460 LC cells transfected by siNC, siLINC00839, oeNC, oeLINC00839, NC mimics, miR-519d-3p mimics and oeLINC00839 with siJMJD6 were examined with CCK-8 assay while apoptosis was examined using flow cytometry. Meanwhile, migration and invasiveness were analyzed using transwell assays. Bindings between LINC00839 and miR-519d-3p, miR-519d-3p and JMJD6 were measured by luciferase reporter assays. RESULTS: LINC00839 was upregulated in LC cells and its knockdown resulted in reduced cell viability, migratory ability and invasion but increased cell apoptosis. MiR-519d-3p was the target gene of LINC00839 and its expression was reduced by LINC00839 overexpression. JMJD6 was directly targeted and suppressed at the level of mRNA and protein expression by miR-519d-3p. Moreover, miR-519d-3p overexpression resulted in low LC cell viability, migration, invasiveness but a high apoptosis rate. Furthermore, mRNA and protein expressions of JMJD6 were upregulated by LINC00839 overexpression. LINC00839 competitively sponged miR-519d-3p, increasing JMJD6 expression, LC cell viability, invasion, migratory abilities and decreasing apoptosis rates in A549 and H460 lung cancer cells, which were hindered after JMJD6 knockdown. CONCLUSIONS: LINC00839/miR-519d-3p/JMJD6 axis mediated cell viability, apoptosis, and migration and invasiveness of lung cancer cells.

4.
Transpl Immunol ; 69: 101478, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34607003

RESUMO

BACKGROUND: Cisplatin (DDP) is used for lung cancer therapy. MicroRNAs, small non-coding RNAs, may contribute to tumorigenesis as well as to drug resistance. We examined regulatory functions of miR-106a-5p in DDP-resistant lung cancer cells. METHODS: Differentially expressed miRNAs were provided by Gene Expression Omnibus (GEO) datasets and RT-qPCR examined RNA levels of miR-106a-5p and Jumonji domain-containing protein 6 (JMJD6), an enzyme causing lysine hydroxylation and arginine demethylation. Bindings were determined by luciferase reporter assay. Additionally, the half maximal inhibitory concentration (IC50) of DDP was determined through Cell Counting Kit-8 (CCK-8) after treated by DDP (0, 6.25, 12.5, 25, 50 and 75 µM) and apoptosis rates were analyzed using flow cytometry. Besides that, migratory ability and invasiveness were examined by transwell. Western blot was for measuring protein levels of Bcl-2, Bax in apoptosis and E-cadherin, N-cadherin in epithelial-mesenchymal transition (EMT). RESULTS: The IC50 value of DDP-resistant A549 (A549/DDP) cells was higher, so were migration, invasion and N-cadherin in EMT while the apoptosis and E-cadherin in EMT were lower versus the parental A549 cells (no DDP resistance). MiR-106a-5p was low expressed in A549/DDP cells while its overexpression caused decreased migration, invasiveness and EMT but promoted apoptosis. JMJD6 was directly targeted and negatively regulated by miR-106a-5p. Inhibited JMJD6 decreased migratory ability, invasion and EMT but improved apoptosis. Moreover, knockdown of miR-106a-5p induced high level of JMJD6, migration, invasiveness and EMT but low apoptosis rates, which were restrained by JMJD6 suppression. CONCLUSION: MiR-106a-5p/JMJD6 axis accelerated cell apoptosis and suppressed invasiveness, migration and EMT in A549/DDP cells.

5.
ACS Omega ; 6(37): 24051-24061, 2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34568683

RESUMO

To study the effect of H2O2 on the content and properties of humic acids (HAs) in lignites, the experimental conditions including oxidation time, H2O2 concentration, and the solid-liquid ratio were investigated. Under the optimum oxidation conditions, the contents of HAs of YL and HB lignite were 45.4 and 40.9%, respectively. The HAs extracted from oxidized and raw lignites were characterized and compared. The results showed that the HAs extracted from oxidized lignites contain more total acidic groups, carboxyl groups, and aliphatic carbon than that in HAs extracted from raw lignites, and their hydrophilic-hydrophobic index value is higher and thermooxidative stability is better than those in HAs extracted from raw lignites. In addition, the composition of polycyclic aromatic hydrocarbons and fluorophore types in HAs extracted from oxidized lignites are similar to the HAs extracted from raw lignites. The results indicated that the oxidation operation can increase the content of HAs in lignites, and simultaneously increase the content of oxygen-containing functional groups and biological activity of HAs, which provided a reference for the subsequent application of HAs.

7.
Sci Total Environ ; 799: 149354, 2021 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-34364276

RESUMO

Heating rate, an important parameter in pyrolysis, not only impacts distribution of pyrolysis products, but also affects evolution of functionality of biochar and further application of the biochar. In this study, an in situ Diffuse Reflection Infrared Fourier Transform Spectra (DRIFTS) technique was used to probe transformation of functional groups of the biochar derived from pyrolysis of cellulose at varied heating rate of 5, 10, 15 and 20 °C/min, aiming to draw an overall picture for the change of functional groups of the biochar versus the heating rate and pyrolysis temperature. The results showed the abundance of -OH, CH and CO experienced a maximum in 410 to 450 °C, depending on the specific heating rates, and then decreased with further increasing temperature via the conversion routes including dehydration, dehydrogenation and cracking. This led to carbonization of the biochar with monotonous increase of abundance of =C-H and CC functionality. Formation of the =C-H had a very close correlation with the removal of -C-H and -OH, especially the -C-H. Cracking of CO was one of the decisive factors for formation of CC. Nevertheless, cracking of C-O-C was much more difficult to be removed than that of CO and -OH, deterring the carbonization and leading to the retainment oxygen in the biochar.


Assuntos
Celulose , Pirólise , Carvão Vegetal , Temperatura
8.
Oxid Med Cell Longev ; 2021: 5529430, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34326916

RESUMO

Accumulating evidence has shown that endothelial progenitor cell-derived exosomes (EPC-Exos) can ameliorate myocardial fibrosis. The purpose of the present study was to investigate the effects of EPC-Exos-derived microRNAs (miRNAs) on myocardial infarction (MI). A miRNA-Seq dataset of miRNAs differentially expressed between EPCs and exosomes was collected. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate the miRNA expression indicated by miRNA-Seq. Immunofluorescence, cell proliferation, and angiogenesis assays were employed to investigate the effects of miRNAs on cardiac fibroblasts (CFs) in vitro. Interactions between miRNAs and their respective targets were examined via immunoblotting, qRT-PCR, and luciferase reporter assays. An MI rat model was constructed, and various staining and immunohistochemical assays were performed to explore the mechanisms underlying the miRNA-mediated effects on MI. miR-363-3p and miR-218-5p were enriched in EPC-Exos, and miR-218-5p and miR-363-3p mimic or inhibitor enhanced or suppressed CF proliferation and angiogenesis, respectively. miR-218-5p and miR-363-3p regulated p53 and junction-mediating and regulatory protein (JMY) by binding to the promoter region of p53 and the 3' untranslated region of JMY. Additionally, treatment of CFs with Exo-miR-218-5p or Exo-miR-363-3p upregulated p53 and downregulated JMY expression, promoted mesenchymal-endothelial transition, and inhibited myocardial fibrosis. Administration of exosomes containing miR-218-5p mimic or miR-363-3p mimic ameliorated left coronary artery ligation-induced MI and restored myocardial tissue integrity in the MI model rats. In summary, these results show that the protective ability of EPC-Exos against MI was mediated by the shuttled miR-218-5p or miR-363-3p via targeting of the p53/JMY signaling pathway.

9.
Sci Rep ; 11(1): 15405, 2021 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-34321599

RESUMO

Cystic fibrosis (CF) is a multi-system disease that is characterized by lung disease due to recurrent airway infection and inflammation. Endocrine complications, such as CF bone disease (CFBD), are increasingly identified as patients are living longer. The cause of CFBD is multifactorial with chronic systemic inflammation theorized to be a contributing factor. Thus, we attempted to identify inflammatory biomarkers that are associated with CFBD. We conducted a retrospective observational study of 56 adult patients with CF with an average percentage predictive forced expiratory volume in one second (ppFEV1) of 73.7% (standard deviation: 30.0) who underwent baseline serum analysis for osteoprotegerin (OPG) and pro-inflammatory biomarkers (IL-1ß, IL-6, IL-8 and TNF-α), and had repeated dual-energy x-ray absorptiometry (DXA) scans separated by at least 2 years to examine correlations between serum biomarkers and bone mineral density (BMD) measurements. Univariate linear regression model analysis demonstrated that serum IL-1ß and IL-8, but not other pro-inflammatory markers, were negatively correlated with baseline BMD results. However, after accounting for confounding variables, only the relationship between IL-8 and left femoral neck BMD remained statistically significant. Additionally, IL-8 level was associated with BMD decline over time. These results suggest that IL-8 might play a unique role in the pathophysiology of CFBD relative to other pro-inflammatory cytokines but further study is warranted before firm conclusions can be made.


Assuntos
Densidade Óssea/genética , Fibrose Cística/sangue , Colo do Fêmur/metabolismo , Interleucina-1beta/sangue , Interleucina-8/sangue , Adolescente , Adulto , Remodelação Óssea/genética , Fibrose Cística/genética , Fibrose Cística/patologia , Colo do Fêmur/patologia , Humanos , Inflamação/sangue , Inflamação/genética , Inflamação/patologia , Masculino , Pessoa de Meia-Idade , Osteoporose/sangue , Osteoporose/genética , Osteoporose/patologia , Fator de Necrose Tumoral alfa/sangue , Adulto Jovem
10.
Chin J Cancer Res ; 33(3): 308-322, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34321828

RESUMO

Objective: α-ketoglutarate (α-KG) is the substrate to hydroxylate collagen and hypoxia-inducible factor-1α (HIF-1α), which are important for cancer metastasis. Previous studies have shown that the upregulation of collagen prolyl 4-hydroxylase in breast cancer cells stabilizes the expression of HIF-1α by depleting α-KG levels. We hypothesized that mitochondrial malic enzyme 2 (ME2) might also affect HIF-1α expression via modulating α-KG levels in breast cancer cells. Methods: We evaluated ME2 protein expression in 100 breast cancer patients using immunohistochemistry and correlated with clinicopathological indicators. The effect of ME2 knockout on cancer metastasis was evaluated using an orthotopic breast cancer model. The effect of ME2 knockout or knockdown on the levels of α-KG and HIF-1α proteins in breast cancer cell lines was determined both in vitro and in vivo. Results: ME2 was found to be upregulated in the human breast cancerous tissues compared with the matched precancerous tissues (P<0.001). The elevated expression of ME2 was associated with a poor prognosis (P=0.019). ME2 upregulation was also related to lymph node metastasis (P=0.016), pathological staging (P=0.033), and vascular cancer embolus (P=0.014). Also, ME2 knockout significantly inhibited lung metastasisin vivo. In the tumors formed by ME2 knockout cells, the levels of α-KG were significantly increased and collagen hydroxylation level did not change significantly but HIF-1α protein expression was significantly decreased, compared to the control samples. In cell culture, cells with ME2 knockout or knockdown demonstrated significantly higher α-KG levels but significantly lower HIF-1α protein expression than control cells under hypoxia. Exogenous malate and α-KG exerted similar effect on HIF-1α in breast cancer cells to ME2 knockout or knockdown. Additionally, treatment with malate significantly decreased 4T1 breast cancer lung metastasis. ME2 expression was associated with HIF-1α levels in human breast cancer samples (P=0.008). Conclusions: Our results provide evidence that upregulation of ME2 is associated with a poor prognosis of breast cancer patients and propose a mechanistic understanding of a link between ME2 and breast cancer metastasis.

11.
Redox Biol ; 46: 102065, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34293554

RESUMO

Although glucose, through pentose phosphate pathway (PPP), is the main source to generate NADPH, solid tumors are often deprived of glucose, hence alternative metabolic pathways to maintain NADPH homeostasis in cancer cells are required. Here, we report that lactate and glutamine support NADPH production via isocitrate dehydrogenase 1 (IDH1) and malic enzyme 1 (ME1), respectively, under glucose-deprived conditions. Isotopic tracing demonstrates that lactate participates in the formation of isocitrate. Malate derived from glutamine in mitochondria shuttles to cytosol to produce NADPH. In cells cultured in the absence of glucose, knockout of IDH1 and ME1 decreases NADPH/NADP+ and GSH/GSSG, increases ROS level and facilitates cell necrosis. In 4T1 murine breast tumors, knockout of ME1 retards tumor growth in vivo, with combined ME1/IDH1 knockout more strongly suppressing tumor growth. Our findings reveal two alternative NADPH-producing pathways that cancer cells use to resist glucose starvation, reflecting the metabolic plasticity and flexibility of cancer cells adapting to nutrition stress.


Assuntos
Glucose , Neoplasias , Animais , Glutamina , Ácido Láctico , Camundongos , NADP/metabolismo , Neoplasias/genética , Via de Pentose Fosfato
12.
Acta Biochim Pol ; 68(4): 593-602, 2021 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-34270886

RESUMO

Recent reports suggest that histone demethylase KDM5A emerges as a new player in the development of drug resistance and thus increases the challenges of chemotherapy. Here, we explore the role of KDM5A in cell proliferation, epithelial-mesenchymal transition (EMT)and its causal association with paclitaxel resistance in lung adenocarcinoma. Paclitaxel-resistant lung adenocarcinoma PTX-Calu-3 cells showed significantly higher IC50 value (7±0.176 µM) upon paclitaxel treatment than lung adenocarcinoma SK-LI-1 (3.6±0.005 nM), Calu-3 (4.3±0.015 nM), and A549 (4.5±0.106 nM) cells. We found that expression of KDM5A and P-glycoprotein (P-gp), which plays a critical role in the development of paclitaxel resistance, were significantly higher in PTX-Calu-3 cells compared to SK-LI-1, Calu-3, and A549 cells.. We observed a significant increase in the expression of mesenchymal markers N-cadherin and vimentin, and a concomitant decrease in expression of E-cadherin and α-catenin in PTX-Calu-3 compared to SK-LI-1, Calu-3, and A549 lung cancer cell lines. Transwell Boyden chamber and wound healing assays further demonstrated that a significantly higher number of PTX-Calu-3 cells were invasive and motile compared to SK-LI-1, Calu-3, and A549 cells, thus supporting the role of KDM5A in metastasis-associated processes. Additionally, a significantly higher expression of KDM5A was observed in lung adenocarcinoma patients' samples compared with adjacent normal tissues as well as in PTX-Calu-3 cells compared toSK-LI-1, Calu-3, and A549 cells, as shown both with histochemistry and real time-polymerase chain reaction (RT-PCR). In summary, these results suggest that KDM5A plays a key role in lung adenocarcinoma by promoting proliferation, EMT, and drug resistance to paclitaxel treatment.

13.
ACS Nano ; 15(6): 10286-10295, 2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34105939

RESUMO

Hydrazine fuel cells are promising sustainable power sources. However, the high price and limited reserves of noble metal catalysts that promote the sluggish cathodic and anodic electrochemical reactions hinder their practical applications. Reflecting the enhanced diffusion and improved kinetics of nanostructured non-noble metal electrocatalysts, we report an efficient zeolitic-imidazole framework-derived trifunctional electrocatalyst for hydrazine oxidation, oxygen, and hydrogen peroxide reduction. Experimental results and theoretical calculations corroborate that the nanocarbon architecture with abundant Co-N species enhances the electronic interaction and optimizes the energy barriers of anodic hydrazine oxidation and cathodic oxygen reduction. The resulting assembled hydrazine-oxygen fuel cell yields a cell voltage and power density of 0.74 V and 20.5 mW cm-2, respectively. Moreover, benefiting from the liquid-liquid diffusion, the hydrazine-hydrogen peroxide cell shows a boosted cell voltage and power density, corresponding to 1.68 V and 41.0 mW cm-2. This work offers a highly active non-noble metal multifunctional electrocatalyst with a pioneering diffusion philosophy in the liquid electrochemical cells.

14.
Sci Total Environ ; 791: 148134, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34118669

RESUMO

Co-hydrothermal carbonization (HTC) of livestock manure and biomass might improve the fuel properties of the hydrochar due to the high reactivity of the biomass-derived intermediates with the abundant oxygen-containing functionalities. However, the complicated compositions make it difficult to explicit the specific roles of the individual components of biomass played in the co-HTC process. In this study, cellulose was used for co-HTC with swine manure to investigate the influence on the properties of the hydrochar. The yield of hydrochar obtained from co-HTC reduced gradually with the cellulose proportion increased, and the solid yield was lower than the theoretical value. This was because the cellulose-derived intermediates favored the stability of the fragments from hydrolysis of swine manure. The increased temperature resulted in the reduction of the hydrochar yield whereas the prolonged time enhanced the formation of solid product. The interaction of the co-HTC intermediates facilitated the formation of O-containing species, thus making the solid more oxygen- and hydrogen-rich with a higher volatility. In addition, the co-HTC affected the evolution of functionalities like -OH and CO during the thermal treatment of the hydrochar and altered its morphology by stuffing the pores from swine manure-derived solid with the microspheres from HTC of cellulose. The interaction of the varied intermediates also impacted the formation of amines, ketones, carboxylic acids, esters, aromatics and the polymeric products in distinct ways.


Assuntos
Celulose , Esterco , Animais , Biomassa , Carbono , Hidrogênio , Hidrólise , Suínos , Temperatura
15.
Signal Transduct Target Ther ; 6(1): 242, 2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34176927

RESUMO

Previous studies demonstrated that superoxide could initiate and amplify LDH-catalyzed hydrogen peroxide production in aqueous phase, but its physiological relevance is unknown. Here we showed that LDHA and LDHB both exhibited hydrogen peroxide-producing activity, which was significantly enhanced by the superoxide generated from the isolated mitochondria from HeLa cells and patients' cholangiocarcinoma specimen. After LDHA or LDHB were knocked out, hydrogen peroxide produced by Hela or 4T1 cancer cells were significantly reduced. Re-expression of LDHA in LDHA-knockout HeLa cells partially restored hydrogen peroxide production. In HeLa and 4T1 cells, LDHA or LDHB knockout or LDH inhibitor FX11 significantly decreased ROS induction by modulators of the mitochondrial electron transfer chain (antimycin, oligomycin, rotenone), hypoxia, and pharmacological ROS inducers piperlogumine (PL) and phenethyl isothiocyanate (PEITC). Moreover, the tumors formed by LDHA or LDHB knockout HeLa or 4T1 cells exhibited a significantly less oxidative state than those formed by control cells. Collectively, we provide a mechanistic understanding of a link between LDH and cellular hydrogen peroxide production or oxidative stress in cancer cells in vitro and in vivo.

16.
ACS Omega ; 6(15): 10281-10287, 2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-34056182

RESUMO

The molecular structure of Baoqing lignite was analyzed by ultimate analysis, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, 13C solid-state nuclear magnetic resonance, and X-ray photoelectron spectroscopy. The results revealed that the aromaticity of Baoqing lignite is 27.64%, and the aromatic structure mainly contains benzene and naphthalene. The aliphatic structure consists of alkyl side chains and cycloalkyl. Oxygen atoms are present in phenol, ether, carbonyl, and carboxyl groups; nitrogen atoms are chiefly in pyridine and pyrrole; sulfur atoms mainly exist in sulfoxide sulfur. The molecular structure model of Baoqing lignite was constructed based on experimental data, and the molecular formula is C184H199O50N2S. The molecular configuration was optimized by adopting the M06-2X basis set in the framework of density functional theory. Moreover, the simulated FTIR spectrum was in good agreement with the experimental spectra, proving the accuracy of the molecular structure. The molecular model of Baoqing lignite contains a majority of aliphatic structures and aromatic rings with a poor condensation degree. Moreover, the aromatic layers irregularly arrange in space.

17.
Sci Total Environ ; 786: 147381, 2021 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-33975118

RESUMO

Swine and chicken manures are abundant solid wastes that can be converted into carbonaceous materials through hydrothermal carbonization (HTC). Owing to their unique biochemical compositions, co-HTC of these two types of manures may have significant implications for the generated products. We investigated the co-HTC of swine manure and chicken manure to understand the influence of the interaction between contrasting manures on the properties of the derived products. The results indicated that co-HTC treatment enhanced the formation of solid product and improved the C and N contents, heating value, and energy yield of the resulting hydrochar. Regarding the ignition temperature and comprehensive combustion index, the combustion properties of the hydrochar were enhanced owing to the mutual effect of the HTC intermediates. Additionally, the interaction of the intermediates significantly impacted the transfer of nitrogenous species and generation of organic acids and organic polymers with fused-ring structures. Therefore, co-HTC processing of animal manures could potentially provide a sustainable pathway for the conversion of animal waste into solid products with improved characteristics compared to those produced by treating the two feedstocks separately.

18.
ACS Appl Mater Interfaces ; 13(21): 24957-24965, 2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34009938

RESUMO

The size effects of metal catalysts have been widely investigated to optimize their catalytic activity and selectivity. However, the size-controllable synthesis of uniform supported metal nanoparticles without surfactants and/or additives remains a great challenge. Herein, we developed a green, surfactant-free, and universal strategy to tailor the sizes of uniform Pd nanoparticles on metal oxides by an electroless chemical deposition method via defect engineering of supports. The nucleation and growth mechanism suggest a strong electrostatic interaction between the Pd precursor and low-defective CeO2 and a weak reducing capacity for low-defective CeO2, resulting in small Pd nanoparticles. Conversely, large Pd nanoparticles were formed on a highly defective CeO2 surface. Combined with various ex situ and in situ characterizations, a higher intrinsic activity of Pd for the CO2-to-CO hydrogenation was found on large Pd nanoparticles with higher electron density owing to their stronger H2 dissociation ability and H-spillover effects, as well as the larger number of oxygen vacancies generated in situ for CO2 activation under hydrogenation conditions.

19.
J Colloid Interface Sci ; 600: 681-690, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34049023

RESUMO

The application of biomass-based carbon materials in electrode materials are usually subject to their deficient adsorption sites as well as sluggish diffusion of electrolyte ions. Herein, flower-like carbons are obtained from the heavy fraction of bio-oil with the auxiliary of Hydrogen-bonded frameworks (HOFs) crystals. During the co-carbonization of the both, the HOFs crystals are removed on account of its poor stability, which directs the formation of flower-like morphology and generates the penetrable meso/macropores across petal-like carbon nanosheets. In addition, the pyrolysis gases serve as the agents for activation to enrich the active sites without the further activation. The degree of graphitization and the contents of pyridine nitrogen for carbon materials could be flexibly adjusted with the contents of HOFs. Owing to the beneficial 3D flower-like structure, high specific surface area (1076 m2/g), large pore volume (2.59 cm3/g), and rational N species, the assembled Zn//BH-4 hybrid supercapacitor reaches a superior energy density of 117.5 Wh/kg at 890 W/kg and maintains 60.7 Wh/kg even at 16.2 kW/kg.


Assuntos
Carbono , Hidrogênio , Capacitância Elétrica , Íons , Óleos Vegetais , Polifenóis , Zinco
20.
Sci Total Environ ; 778: 146321, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33725606

RESUMO

Heavy organics in bio-oil generally refer to the sugar oligomers and lignin-derivatives. They are important fractions in bio-oil and their effective conversion in hydrotreatment determines carbon yield from biomass or bio-oil to biofuel. Fates of the heavy organics largely determine intrinsic reaction behaviors of bio-oil during hydrotreatment. The heavy organics in bio-oil have high tendency towards polymerization upon thermal treatment, which is one of the main precursors for coke formation and catalyst deactivation. Furthermore, the heavy organics have some other unique characteristics in hydrotreatment such as the steric hindrance for contacting active sites on surface of catalyst. How to effectively convert the heavy organics has been regarded as the bottle-neck issue in hydrotreatment of bio-oil and the key barrier in the roadmap from biomass to biofuels. Thus, this review particularly focuses on the progress in understanding reaction behaviors of the heavy organics in hydrotreatment of bio-oil, a central challenge to be resolved. The results indicated that coke formation from heavy organics in bio-oil remains main obstacle in hydrotreatment and further fundamental studies are required to develop suitable catalyst and process to stabilize the heavy organics in bio-oil. In particular, the mechanism for coke formation from the heavy species of varied chemical family should be clarified and corresponding measures should be developed to tackle high tendency of coking. Techno-economic feasibility should be considered in the first place in development of catalysts or process for tackling the heavy fractions of bio-oil.


Assuntos
Biocombustíveis , Óleos Vegetais , Biocombustíveis/análise , Biomassa , Catálise , Polifenóis
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