CHEMICAL ENGINEERING JOURNAL
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2020
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IF 10.652
Ziqiu Ren,Na Wang,Peicheng Wei,Minghuan Cui,Xin Li,Chaochao Qin
As a classical electron transport layer, the high crystallinity TiO 2 has been widely used in perovskite solar cells (PSCs), however, its high-temperature preparation process elevates the fabrication cost and limits its application. Here, we report an ultraviolet-ozone assisted strategy to modify low-temperature TiO 2 interface for PSCs. In addition to the more appropriate work function and reinforced built-in potential, the lattice strain of perovskite films crystallized on modified TiO 2 has also been released in some degree. Ultrafast transient absorption technique is employed to provide a deep insight into the carrier dynamics, revealing that less non-radiative recombination exists in the modified device. Interestingly, transient surface photovoltage results demonstrate that ultraviolet-ozone modification can efficiently suppress the decomposition of perovskite films under light illumination. Taking advantage of these facts, this device exhibits better efficiency and remarkable stability. This demonstrated low-temperature strategy is a promising way for fabricating low-cost, efficient and stable perovskite device.
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FUEL
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2020
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IF 5.578
Fengfei Chen,Jinbao Liu,Taishun Yang,Suya Yin,Baoting Su,Maiying Xie,Bin Dai,Sheng Han,Yuan Xue
Precipitation of n-alkanes at low temperatures is the main factor that affects the cold flow properties of diesel fuel. In order to improve the clod flow properties of diesel fuel, maleic anhydride-methyl benzyl acrylate copolymer (MA-MB) were synthesized and modified with long-chain fatty amine and long-chain fatty alcohol (RNH 2 and ROH, R = C 14 , C 16 , C 18 ) to obtain a series of aminated copolymers R 1 MA-MB (R 1 = N 14 , N 16 , N 18 ) and esterified copolymers R 2 MA-MB (R 2 = C 14 , C 16 , C 18 ). These copolymers were characterized by gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectroscopy, and proton nuclear magnetic resonance ( 1 H NMR), and the oil affinity and oil solubility were studied by the static contact angle. The influences of them used as pour point depressants (PPDs) on the cold flow properties of diesel fuel were investigated. Results indicate that the esterified copolymers exhibit a better depression effect in depressing the solid point (SP) and cold filter plugging point (CFPP) than that of aminated copolymers. Among that, C 14 MA-MB exhibited the most considerable reduction on the SP and CFPP by 24 and 8 °C at 500 ppm addition, respectively. In addition, the depression mechanism was explored by differential scanning calorimetry, rheological analysis and polarizing optical microscopy. The analysis shows that C 14 MA-MB changed the crystal behaviors by modifying the crystal growth direction, restraining the crystal accumulation, and retarding the formation of large crystals, thus enhancing the cold flow properties of diesel fuel. Therefore, the synthesized copolymers are the highly effective PPDs of diesel fuels.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2020
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IF 16.683
Jingzhen Zhang,Longhui Zheng,Fu Wang,Chao Chen,Haodong Wu,Sajjad Ahmed Khan Leghari,Mingce Long
Isopropanol is frequently employed as the electron donor to facilitate hole transfer and promote photocatalytic H 2 O 2 production. However, the role of alcohols can be more complicated due to the interaction with TiO 2 . According to a comparison of aliphatic, aromatic and aromatic heterocyclic alcohols on photocatalytic H 2 O 2 production on TiO 2 , furfural alcohol (FFA) displays superior capability to others. The presence of alcohols with aromatic structures can significantly accelerate formation and suppress decomposition of H 2 O 2 . Moreover, furfural alcohol tends to form more stable complexes on TiO 2 surface, which can negatively shift the flat band position, induce visible light activity, and boost two-electron reduction of oxygen. The altered electron transfer pathway for H 2 O 2 production was indicated by the Koutecky-Levich plots, the less pH dependence, and the signals of peroxide species in Raman spectra. This study brings insights for modulating the interfacial oxygen reduction and designing highly efficient and selective H 2 O 2 production photocatalytic systems.
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LWT-FOOD SCIENCE AND TECHNOLOGY
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2020
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IF 4.006
Dandan Qi,Chengying Ma,Wenwen Wang,Licui Zhang,Jinghong Hao,Jianke Li
The aim of this study is to reveal differences of volatile components of royal jelly (RJ) produced by different honeybee stocks. Volatile components of three RJ samples from high and low RJ production honeybee stocks were extracted by headspace-solid phase micro-extraction and analyzed by gas chromatography-mass spectrometry. Principal component analysis, hierarchical clustering analysis of the volatile components are suggestive of the fact that honeybee stock selected for increasing RJ yields (royal jelly bees) has shaped distinct volatile component profile compared with the unselected Italian bees. In total, 37 components were identified that could distinguish three RJ samples, including 5 aldehydes, 5 esters, 5 alkanes, 14 alcohols and phenols, 4 ketones and 4 other components. Our study provides the first characterization of volatile components in RJs and uncovered the differences among royal jelly secreted by different bee stocks.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2020
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IF 16.683
Jingzhen Zhang,Chunyang Yu,Junyu Lang,Yongfeng Zhou,Baoxue Zhou,Yun Hang Hu,Mingce Long
Photocatalytic H 2 O 2 production (PHOP) on graphitic carbon nitride (GCN) at neutral pHs is limited by the sluggish oxidation of sacrificial alcohols and insufficient protons. In our work, the PHOP over a series of K intercalated triazine (KTCN) or tri-s-triazine units (KTTCN) reached 11–32 folds of GCN in the presence of only 0.5 vol% isopropanol, and a positive correlation between the H 2 O 2 production and the K contents was found. The critical role of K was revealed as that K intercalation creates Lewis acidic sites for isopropanol adsorption and strengthens Lewis basic sites for hydrogen abstraction and proton release. The improved alcohol oxidation and enhanced O 2 chemisorption synergistically result in dramatically accelerated PHOP over KTTCN. The findings provide the understanding of the preliminary active site dependent PHOP mechanism and bring insights for design of carbon nitride polymers with desirable photocatalytic performance.
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JOURNAL OF CATALYSIS
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2021
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IF 7.92
Shuhui Yang,Xi Ke,Qizan Chen,Runda Huang,Weizhe Wang,Kunqiang Wang,Kaixiang Shu,Chen Tu,Zhaoqiang Zheng,Dongxiang Luo,Haowei Huang,Menglong Zhang
Constructing mixed dimensional materials have been regarded as an outstanding approach to maximum the advantages from materials of different dimensions. In this work, we prepared a mixed dimensional photocatalyst based on Formamidinium lead bromide (FAPbBr 3 ) perovskite and 2D materials (2DMs). The aim of this work is to utilize distributions of the active sites in 2DMs, through growing FAPbBr 3 on the different position of 2DMs, the concentration of photogenerated charges is manipulated, thus conducting different reactions. A pre-treatment using HBr to increase the unsaturated bonds in MoS 2 presents significant influence on the FAPbBr 3 growth and its photocatalytic product. The scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) confirm that the perovskite nanoparticles were well loaded on the 2D materials. The photocatalytic process and the heterojunction arrangement are demonstrated by X-ray photoelectron spectroscopy (XPS), time-resolved photoluminescence (TRPL), electron paramagnetic resonance (EPR) and surface photovoltage microscopy (SPVM). By adjusting the weight ratios and growth of FAPbBr 3 on the top of 2DMs, the optimized composite photocatalyst (with 30 wt% of FAPbBr 3 ) exhibits remarkable photoactivity for oxidation of benzyl alcohol into benzaldehyde (30 wt% FAPbBr 3 @WS 2 performed 75.9% conversion in 4 h, approximately 9-fold than the pure 2DMs). Meanwhile, by growing FAPbBr 3 on the edge of 2DMs, benzoic acid is obtained as the product. Although longer reaction time is needed, the photocatalyst performs outstanding activity (30 wt% FAPbBr 3 @MoS 2 reached 84.5% conversion in 5 h).
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Processes
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2021
·Vol. 9
·期 9
·1487
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IF 2.847
Muhammad Faizan,Kifayat Ullah Khan Niazi,Hasnain Nawaz,Niaz Muhammad,Hao Li,Fei Dai,Ruirui Zhang,Ruixia Liu,Suojiang Zhang
In recent work, deep eutectic solvents (DESs) as ionic liquid analogues have been abundantly used in catalysis. Herein, vanadium phosphorus oxide (VPO) catalysts were synthesized from mono-, bi-, and tri- metallic DES of Nb, Zr, and Mo metal dopants as structure-directing agents and electronic promoters for n-butane selective oxidation towards maleic anhydride. Higher MA selectivity and larger n-butane conversion was successfully obtained using the newly developed catalysts, while oxidation by-product COx(CO, CO2) was minimized. Characterization techniques including FTIR, DSC, XRD, TEM, SEM, EDS, Raman spectroscopy, TGA, XPS, and NH3-TPD were employed to fully characterize the DESs, precursors and catalysts. This work led to an increase of 7.8% in MA mass yield with 16% more n-butane conversion as compared to an unpromoted VPO catalyst. Moreover, the utilization of a low-carbon alkane brought in a green impact on the chemical plant as well as the environment.Keywords:deep eutectic solvent;vanadium phosphorus oxide;n-butane selective oxidation;structure directing agent;electronic promoter
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2021
·Vol. 413
·期 23
·5789-5798
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IF 4.157
Zheng Chengyu,Zhou Qinan,Wang Zhenhe,Wang Jun
In recent years, the invasive cypress bark beetle ( Phloeosinus aubei ) has caused extensive damage to Platycladus orientalis plants in China, but its infestation is hard to monitor in the early stages. In this study, gas chromatography-mass spectrometry (GC-MS) was initially employed to investigate the volatile organic compound (VOC) emissions of P. aubei- infested P. orientalis saplings. The emissions of total sesquiterpenes were dominating (84−86% of total VOCs) and increased by 3.09-fold in P. aubei- damaged P. orientalis samples compared to undamaged samples, and the monoterpenes, aromatic compounds, and ketone emissions also had varying degrees of increase between 1.39-fold and 5.65-fold. Based on this variation, gas chromatography-ion mobility spectrometry (GC-IMS) was applied, as an untargeted analytical approach, to discriminate P. orientalis samples with different invasive severity. Two different features derived from GC-IMS data were adopted as the input information for classification and prediction models. Results showed that grid search support vector machine (GS-SVM) combined with multilinear principal component analysis (MPCA) based on spectral fingerprint achieved the best classification performances (> 88.98%), and partial least squares discriminant analysis (PLSR) method can accurately predict the pest numbers ( R 2 > 0.9423 and RMSE < 0.9827). In a word, the VOC profiling-based approach had the potential for evaluating P. aubei invasive severity and pest management.
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PubMed
高影响因子
DALTON TRANSACTIONS
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2021
·Vol. 50
·期 30
·10501-10514
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IF 4.39
Xuqiang Hao,Dingzhou Xiang,Zhiliang Jin
Herein, a novel amorphous monodisperse Co3O4 quantum dots/3D hexagonal CdS single crystals (0D/3D Co3O4 QDs/CdS) p–n heterojunction was constructed by a simple hydrothermal and electrostatic self-assembly method. The amorphous monodispersed Co3O4 QDs (≈4.5 nm) are uniformly and tightly attached to the surface of the hexagonal CdS single crystals. The sample, 0.5% CQDs/CdS exhibits outstanding hydrogen evolution activity of 17.5 mmol h−1 g−1 with a turnover number (TON) of 4214, up to 10.3 times higher than that of pure CdS. The enhanced photocatalytic activity can be attributed to the synergistic effect of the p–n heterostructure and the quantum confinement effect of Co3O4 QDs, which significantly promoted the separation efficiency of photo-generated electrons and holes. Additionally, the sulfur vacancy also can act as electron trappers to improve carrier separation and electron transfer. The photoelectrochemical and time-resolved fluorescence (TRPL) results further certify the effective spatial charge separation. This work gives an insight into the design of the 0D/3D Co3O4 QDs/CdS p–n heterostructure for a highly efficient photocatalysis.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2021
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IF 19.503
Zhenfei Yang,Xinnian Xia,Wenwu Yang,Longlu wang,Yutang Liu
The molecular oxygen activation (MOA) process tends to be the rate-limiting step for photocatalytic selective organic transformation such as aromatic alcohol oxidation . Herein, using the plasmonic 0D/2D W 18 O 49 /ZnIn 2 S 4 (WOZ) heterojunctions as a model system, we firstly shed light on the ultra-efficient MOA origin of the synergism of photothermal effect and continuous hot electrons injection through both experimental and DFT calculations. This synergistic action not only enhances the generation rate of •O 2 ¯ and reduces the activation energy barrier, but also significantly increases the adsorption of the O 2 and activates it more easily, thus achieving efficient photocatalytic selective oxidation of benzyl alcohol to benzaldehyde. Meanwhile, the charge separation and transfer processes involved in O 2 activation can be further optimized with the Z-scheme transfer route. This work would provide an exciting opportunity to construct more active photothermal catalysts with ultra-high efficiency of MOA for a wide variety of organic transformations with solar energy.
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MACROMOLECULAR CHEMISTRY AND PHYSICS
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2021
·Vol. 223
·期 12
·2100321
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IF 2.527
Guanchen He,Heng Li,Junpeng Zhao
One-step synthesis of well-defined block copolymer is of great fundamental and practical values. Here, an aromatic-aliphatic block copolyester is one-step synthesized from the mixture of phthalic anhydride (PA), cyclohexene oxide (CHO), and δ -valerolactone ( δ -VL) at room temperature in the presence of a metal-free Lewis pair catalyst consisting of triethylborane and excess phosphazene base. Alcohol-initiated ring-opening alternating copolymerization of PA and CHO occurs first and selectively because of the overwhelmingly higher activity of PA than CHO and δ -VL toward the reaction with base-activated hydroxy species. Only after full conversion of PA is reached can ring-opening polymerization of δ -VL occur from the terminus of the aromatic polyester so that a well-defined (AB) n C m type block copolyester is formed. The two polymerizations are both highly chemoselective without homopolymerization of CHO or extensive transesterification reactions. Owing to the sequence-selective and living characteristics of the terpolymerization, hepta- and undecablock copolyesters with controlled molar mass and low dispersity are obtained through addition of the three-component monomer mixture in batches. Applicability of the method to propylene oxide and ε -caprolactone is also examined.
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Molecular Catalysis
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2021
·
IF 5.062
Wei Luo,Jiagui Hu,Jiapeng Lu,Huili Zhang,Xiaoping Wang,Yuantao Liu,Liqing Dong,Xiaobin Yu
ω-transaminase can mediate the asymmetric synthesis of chiral amines from aldehydes and ketones , which has important value in the synthesis of pharmaceutical intermediates. A novel ω-transaminase derived from Paracoccus pantotrophus ( Pp TA) was obtained and cloned in E. coli BL21(DE3) for expression. The enzyme has high activity for 2-ketobutyric acid and benzylamine , as well as for aromatic compounds with side chains longer than ethyl aliphatic hydrocarbons . Molecular simulation showed that the S-pocket in the active center is larger than those of other ω-transaminases. Thereafter, a whole-cell catalytic system was designed to prepare l -2-aminobutyric acid by cascading Pp TA and other enzymes. By using several strategies (regulation of RBS intensity, by-product decomposition and cofactor self-sufficiency), whole-cell cascade biocatalysis showed a high ee value (> 99%) and high yield (71%) in one pot reaction . This study therefore proposes an efficient biocatalyst for the synthesis of unnatural amino acids with the participation of ω-transaminase.
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