Nano Energy
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2019
·
IF 15.548
Zhenyu Sun,Rupeng Huo,Changhyeok Choi,Song Hong,Tai-Sing Wu,Jieshan Qiu,Chao Yan,Zishan Han,Yongchao Liu,Yun-Liang Soo,Yousung Jung
Electrochemical ammonia production under ambient conditions remains a grand challenge. Herein, we demonstrate that efficient binding and reduction of N 2 at low overpotentials can be realized over WO 3 with tailored surface oxygen vacancies , as predicted by density functional theory studies and evidenced by an NH 3 yield rate of 4.2 μg NH3 h −1 mg cat. −1 and a faradaic efficiency of 6.8% at −0.12 V ( vs . the reversible hydrogen electrode). A high NH 3 faradaic efficiency of up to 12.8% is obtained at an overpotential of only 80 mV, which can even be further improved by increasing the electrolyte pH to suppress the competing hydrogen evolution reaction . This low-cost metal oxide holds great appeal as one of the most promising electrocatalysts for efficient N 2 fixation.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
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2019
·Vol. 54
·期 17
·11713-11725
·
IF 3.442
Zhang Xinfang,Shao Ziqiang,Zhou Yi,Wei Jie,He Weidong,Wang Shuo,Dai Xiaofu,Ren Jiaying
Because of irreversible agglomeration in the dehydrating process, the wet storage and transport of cellulose nanofibres (CNF) are the serious issues that need to be resolved in the commercialization and application of CNF. In this study, silanized cellulose nanofibres (Si-CNF) were prepared by modifying CNF with phenyltrimethoxysilane (PTS). Moreover, a mixture of redispersed Si-CNF and mineral oil was treated by combining ultrasound and high-pressure homogenizer to prepare Pickering emulsions. Different ratios of CNF/PTS were prepared and redispersed, and their morphological characteristics, thermal performance, rheological properties, zeta potential, and size distribution were analysed to evaluate the changes occurring during modification. The results show that the obtained Si-CNF demonstrates excellent redispersibility in water. The viscosity of the redispersed product exhibits the best suspension stability with the particle distribution uniform at the nanoscale when the addition amount of PTS is 0.18 mmol/g. Rheological and dynamic light scattering results have shown that the Pickering emulsion maintains the best dispersion stability at a concentration of 0.02% and remains stable after 7 days of storage. PTS modified the hydrophobicity of the CNF and provided alternative routes for application of CNF and Pickering emulsions.
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EUROPEAN POLYMER JOURNAL
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2019
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IF 3.621
Yingying Li,Runan Gao,Jian Li
Energy saving materials are economically and environmentally beneficial as they effectively reduce energy consumption and greenhouse gas emissions. In this study, energy saving wood composite was prepared by injecting a methyl methacrylate dispersion containing a mixture of VO 2 (M)@SiO 2 core-shell nanocomposites and thermochromic microcapsules into wood templates. APTS was added to stabilize the suspension. The good compatibility between the injected substances and the wood template benefited from the PMMA and APTS that filled the cell lumen and bonded the substances, leading to energy saving wood composite with excellent dimensional stability, optical properties, and mechanical performance. More importantly, the energy saving wood composite exhibited outstanding temperature regulatory ability by shielding needless infrared radiation, resulting in thermal comfort. The unique properties of the energy saving wood composite could potentially be applied in building, furniture, thermal insulation, energy conversion, energy storage, and conservation.
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NANOTECHNOLOGY
·
2019
·Vol. 30
·期 25
·255703
·
IF 3.399
Ning Li,Xun Cao,Tianci Chang,Shiwei Long,Ping Jin
Pursuing excellent photochromic (PC) properties is still a longstanding challenge for energy-efficient smart coatings. Herein, we have prepared a novel series of self-coated crystalline WO3-amorphous WO3−x homojunctions by a one-step hydrothermal process, in which oxalic acid was used as a capping agent to prevent polycondensation and the crystallization of [WO6]. The as-prepared nanopowders with tight interfaces have a large specific surface area and rich surface electrons, which leads to a dramatic PC property reaching up to ΔTsol = 64.74% at the near-infrared (NIR) range of 1000–2600 nm with high luminous transmittance (Tlum = 94.6% in the virgin state and Tlum = 32.47% in the colored state). Meanwhile, the as-prepared crystalline WO3-amorphous WO3−x homojunction reveals fast reversible PC circulation; most particularly, the self-bleaching rate increases at least three times—the self-bleaching time is less than 8 h. Moreover, as the microstructure of the homojunction is tuned, the solar modulation range can be selective and tuned, so that the solar modulation efficiency is up to the best energy-saving state by controlling the main absorption according to the solar energy distribution.
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PubMed
高影响因子
BIOELECTROCHEMISTRY
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2019
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IF 4.474
Yiyong Wu,Peihong Deng,Yaling Tian,Ziyu Ding,Guangli Li,Jun Liu,Zavuga Zuberi,Quanguo He
A tryptophan (Trp) molecularly imprinted electrochemical sensor was fabricated by drop-coating an imprinted chitosan film on the surface of a glassy carbon electrode modified with multi-walled carbon nanotubes (MIP-MWCNTs/GCE). The surface morphology and electrochemical properties of the MIP-MWCNTs/GCE were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV), respectively. The formation of hydrogen bonds between the functional polymer and the template molecule was confirmed by infrared spectroscopy . The electrochemical performance of the MIP-MWCNTs/GCE with Trp showed that the signal of the oxidation current of Trp obtained with MIP-MWCNTs/GCE was significantly enhanced relative to that of the uncovered GCE, indicating that the modified electrode can accelerate electron transfer and has strong selectivity for Trp. The experimental conditions were optimized in parallel, and under the optimal conditions, the MIP-MWCNTs/GCE showed a good linear relationship between the Trp oxidation peak current and Trp concentrations in the ranges of 2.0 nM–0.2 μM, 0.2 μM–10 μM and 10 μM–100 μM The limit of detection (LOD) was 1.0 nM (S/N = 3), and the modified electrode had good reproducibility and stability. Finally, the MIP-MWCNTs/GCE was successfully applied to the determination of Trp in the human serum samples.
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PubMed
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
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2019
·Vol. 166
·期 13
·D638
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IF 3.12
Pengfei Xu,Xiaohong He,Junwei Mao,Yongming Tang
In this paper, Ti/SnO2-Sb/Ce-PbO2 anode is electrodeposited from MSA bath, and the effect of Ce3+ concentration in bath on the phase composition and morphology of lead dioxide electrode is elucidated. It is found that with the addition of 2 mM Ce3+ ion to the bath the Ce-PbO2 anode exhibits highest stability in 0.5 M H2SO4, and cerium exists as Ce (IV) in the PbO2 film. The electrocatalytic activity of lead dioxide anode for phenol removal is slightly enhanced by the inclusion of Ce. The significant improvement in electrocatalytic activity can be achieved by the addition of small amount of Bi3+ ion to the bath containing Ce3+ ion. In this study, electrocatalytic activities of various anodes follow the order: Ce,Bi-PbO2 > Ce-PbO2 > undoped PbO2 > Bi-PbO2.
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FUEL PROCESSING TECHNOLOGY
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2018
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IF 3.956
Ting Lu,Yucui Hou,Weize Wu,Muge Niu,Wei Li,Shuhang Ren
Carboxylic acids are considered as an important group of chemicals. Direct conversion of cellulose to formic acid (FA) by vanadium(V(V))-contained catalyst is of significant conceptual and practical interest. A second metal (from Mg(II), Ca(II), Al(III), Cr(III), Mo(VI), Mn(II), Cu(II), or Fe(III)) incorporated into V(V)-contained catalyst system was screened to further improve the oxidation of cellulose by O 2 to yield FA. Fe(III) exhibited the best performance and effects of reaction parameters on the conversion of cellulose in NaVO 3 -FeCl 3 -H 2 SO 4 aqueous solution were investigated. Cellulose could be rapidly converted, and the yield of FA (66.8%) was higher than that obtained by the single use of FeCl 3 (48.4%) or NaVO 3 (57.6%). The conversion of cellulose in another V(V)-contained catalyst system (H 5 PV 2 Mo 10 O 40 ) was explored to verify the universal enhancement of FeCl 3 . Influences of the second metal Fe(III) on the V(V)-contained catalyst system and mechanism of cellulose oxidation in the V(V)-Fe(III)-H 2 SO 4 system were studied. Compared with single use of V(V), the employment of Fe(III) alone is not active enough in the oxidative C C bond cleavage . V(V) other than Fe(III) is the main active species for selective oxidation of substrates. The incorporation of Fe(III) and V(V) shows both synergistic and competitive relationships. Both the synergistic and competitive effects are beneficial to increase FA yield, as they promote the oxidation of V(IV) to V(V), increase oxidative ability, and inhibit the overoxidation to by-product CO 2 . The catalyst system was reused four times without decline in activity.
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高影响因子
ACS Catalysis
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2018
·
IF 11.384
Guoxue Liu,Wei Li,Ran Bi,Christian Atangana Etogo,Xin-Yao Yu,Lei Zhang
Despite the ultrahigh energy density of rechargeable lithium–oxygen (Li-O2) batteries, their practical use is still hindered by the poor performance of electrocatalysts. Recently, porous and hollow nanostructured catalysts have been found to be promising electrocatalysts toward the ORR/OER to improve the performance of Li-O2 batteries. However, the catalytic activities of the catalysts are still insufficient and the nanopores are easily clogged by the insoluble discharge products. Herein, highly porous and hollow TiO2–x nanoboxes (TiO2–x NBs) with large surface areas, increased oxygen vacancies, and high grain boundary density have been developed as an electrocatalyst for Li-O2 batteries via a cation-assisted synthetic approach. The Li-O2 batteries with TiO2–x NBs as the electrocatalyst exhibit a high specific capacity of 8569 mA h g–1, excellent rate capability, and long cycle life up to 200 cycles when the capacity is limited to 1000 mA h g–1. Moreover, this cation-assisted approach for fine-tuning the nanostructure could be an innovative strategy to design efficient electrocatalysts for high-performance Li-O2 batteries.
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高影响因子
Catalysts
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2018
·Vol. 8
·期 1
·37
·
IF 3.465
Yang Zheng,Yangyang Guo,Lei Luo,Tingyu Zhu
The performance of activated carbon (AC) modified by different methods was compared for its catalytic degradation of ortho-chlorophenol (o-CP). For the chemically treated AC, the catalytic effect of AC–NH3·H2O was superior to the other catalysts examined, having ano-CP removal efficiency of 82.2% at 330 °C. For the metal-modified catalysts, AC–V and AC–Co showed similar removal performances of 93.2% at 330 °C. N2adsorption-desorption isotherms, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and gas chromatography—mass spectrometry (GC-MS) analyses were used to characterize the reaction products, and different reaction mechanisms were proposed for both AC–NH3·H2O and AC–V according to the results. Complete oxidative degradation ofo-CP was achieved by AC–V, with AC–NH3·H2O leading to the formation of additional dioxins. It can be deduced that a risk of dioxin synthesis and escape during the regeneration process is possible when nitrogen-modified carbon is used in selective catalytic reduction (SCR) denitrification reactions, especially in the presence of chlorine atoms, benzene rings, and oxygen.Keywords:catalysis;modified carbon;ortho-chlorophenol;degradation mechanism
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2018
·
IF 6.735
Amina,Xiongyuan Si,Kang Wu,Youbin Si,Balal Yousaf
In this study, a modified Fenton system using calcium peroxide (CaO 2 ) powder, as an effective source of hydrogen peroxide (H 2 O 2 ), for the degradation of sulfamethoxazole (SMX) in aqueous solution was investigated. Our results indicated that degradation of SMX in Fe(II)-EDTA catalyzed CaO 2 system was readily more efficient than in Fe(II) catalyzed CaO 2 system. The SMX degradation efficiency was found maximum at pH 6.0 and SMX degradation was suppressed as the initial solution pH was increased. Nevertheless overall removal efficiency in this system was favorable near to neutral pH. In addition, it was observed that the higher bicarbonates (HCO 3 − ) contents had a considerable scavenging ability to SMX degradation while low concentration exhibited auspicious role. The presence of chlorides (Cl − ), nitrates (NO 3 − ), sulfates (SO 4 2− ), and humic acid (HA) could improve SMX removal in this Fenton-like system. Furthermore, chemical probe and radical scavenging activity confirmed the formation of hydroxyl (HO ) and superoxide (O 2 − ) radicals, and also described that the SMX degradation was predominantly due to the HO -induced oxidative destruction. Electron paramagnetic resonance (EPR) studies for different systems, different pH values and different reaction times were carried out to determine the HO radical intensities. EPR results showed that HO intensities were higher in Fe(II)-EDTA catalyzed CaO 2 system, at pH 6.0 and at 90 s reaction time, respectively. Intermediate products of SMX were identified and possible mechanism of SMX degradation was suggested. In conclusion, this work provided comprehensive knowledge for the use of Fe(II)-EDTA catalyzed CaO 2 system for remediation of SMX contaminated sites.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2018
·
IF 11.698
Liping Ren,Wei Zhou,Bojing Sun,Haoze Li,Panzhe Qiao,Yachao Xu,Jiaxing Wu,Kuo Lin,Honggang Fu
Defect-engineered magnetic γ-Fe 2 O 3 ultrathin nanosheets/mesoporous black TiO 2 hollow sphere heterojunctions (γ-Fe 2 O 3 /b-TiO 2 ) are fabricated by a metal-ion intervened hydrothermal technique and high-temperature hydrogenation, which exhibit wide-spectrum response and magnetic separation. The specific surface area, pore size and pore volume of the resultant γ-Fe 2 O 3 /b-TiO 2 with hollow structure are ∼63 m 2 g −1 , 10.5 nm and 0.14 cm 3 g −1 , respectively. After surface hydrogenation, α-Fe 2 O 3 nanosheets are converted to γ-Fe 2 O 3 ultrathin nanosheets (∼6 nm) combined with the formation of surface defects. The ultrathin nanosheet structure facilitates the surface engineering and also favors the diffusion and transportation of photogenerated charge carriers. The apparent rate constant (k) of defect-engineered γ-Fe 2 O 3 /b-TiO 2 photocatalytic degradation biotoxic tetracycline is ∼3 times higher than that of α-Fe 2 O 3 /b-TiO 2 under AM 1.5 irradiation. The enhancement is attributed to the introduction of narrow bandgap unit-cell-thick γ-Fe 2 O 3 nanosheets, the hollow structure and the defect engineering, which are beneficial to solar-light-harvesting and rapid electron transport, and spatial separation of photogenerated charge carriers. The photocatalytic degradation mechanism is also proposed. The novel magnetic γ-Fe 2 O 3 /b-TiO 2 heterojunction is a promising photocatalyst for recovering the domestic sewage in environment.
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高影响因子
ACS Sustainable Chemistry & Engineering
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2018
·
IF 6.14
Muhammad Tariq,Waqas Qamar Zaman,Wei Sun,Zhenhua Zhou,Yiyi Wu,Li-mei Cao,Ji Yang
Minimization of noble metal contents along with enhancement in electrochemical properties with high durability is a major challenge to be overcome for commercializing water electrolyzers and cheap energy storage devices. Sluggish kinetics of the oxygen evolution reaction (OER) within the electrolytic cell and high energy demand to form O═O bonds have attracted more responsiveness to this area. We report the OER beneficial mixed oxide composite of molybdenum and iridium oxides by a facile hydrothermal method. Adhered IrO2 nanoparticles on MoO3 large particles synergistically possessed a robust nature toward harsh acidic water electrolysis as compared to an alkaline environment. Mass specific OER activity of iridium active centers was greatly enhanced by 7-fold, twice the current density, and was attributed to electronic modulation of noble metal. Enhanced surface area and the existence of highly oxidative species in the O(1s) spectrum of IrO2 and two doublet regions in the X-ray photoelectron spectrum of molybdenum metal were found, accountable for the robust performance. Prepared composite possessing only 30% molar fraction of noble metal presented an excellent long-term stability for 40 000 s. Reduction in the Tafel slope from 57 to 77 mV dec–1 for IM-30 and IrO2 respectively was observed. The conducted research will open up new avenues for more applications of molybdenum oxides and their derivatives for water splitting.
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