JOURNAL OF BIOTECHNOLOGY
·
2024
·
IF 4.1
Bingbing Xia,Zhiwei Li,Jinao Wei,Ganpeng Hu,Jingwen Yang,Hongbin Zhang,Xueqin Hu
Dextranases are hydrolases that exclusively catalyze the disruption of α−1,6 glycosidic bonds . A series of variant enzymes were obtained by comparing the sequences of dextranases from different sources and introducing sequence substitutions. A correlation was found between the number of amino acids in the 397–401 region and the hydrolytic process. When there were no more than 5 amino acids in the 397–401 region, the enzyme first hydrolyzed the dextran T70 to a low molecular weight dextran with a molecular weight of about 5000, then IMOs 1 appeared in the system if the degradation continued, showing a clear sequential relationship. And when there are more than 5 amino acids in the 397–401 region, IMOs were produced at the beginning of hydrolysis and continue to increase throughout the hydrolytic process. At the same time, we investigated the enzymatic properties of the variants and found that the hydrolytic rate of A-Ca was 11 times higher than that of the original enzyme. The proportion of IMOs produced by A-Ca was 80.68%, which was nearly10% higher than the original enzyme, providing a new enzyme for the industrial preparation of IMOs.
研究领域:
生物化学
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酶学
·
分子生物学
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产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2015
·
IF 2.752
Na Zhao,Siwen Li,Xin Zhang,Xinyue Huang,Jinyi Wang,Ruimin Gao,Jianshe Zhao,Junlong Wang
Photocatalytic oxidative desulfurization of dibenzothiophene (DBT) with H 2 O 2 (30%) and Ag/ALa 4 Ti 4 O 15 (A = Ca, Sr and Ba) as the photocatalysts were studied. Ag cocatalyst-loaded ALa 4 Ti 4 O 15 (A = Ca, Sr and Ba) were synthesized by incipient wetness. Reaction time, temperature and the amount of hydrogen peroxide were investigated as the important parameters for optimization of the reaction and a potential removal mechanism of photocatalytic oxidation was proposed. Ag (2 wt%)/CaLa 4 Ti 4 O 15 and Ag (1 wt%)/BaLa 4 Ti 4 O 15 were found to give remarkable catalytic activity and high selectivity for catalytic experiments. Actually, 99.0% and 98.0% of DBT were converted respectively according to the desulfurization tests. Moreover, these two catalysts were characterized by infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray photoelectron spectrum (XPS).
研究领域:
环境科学
·
材料科学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Wenjia Yang,Wen Cui,Lin Yang,Guo Zhang,Xiaofang Li,Yu Shen,Fan Dong,Yanjuan Sun
Considering that the structural differences could dictate the photocatalytic efficiency, the cubic SrTiO 3 (STO) and tetragonal CaTiO 3 (CTO) were developed to illustrate the structure–activity relationship. The STO with cubic structure demonstrates much higher photocatalytic toluene removal efficiency ( ca. 80.0%) than that of CTO ( ca. 20.0%), which can be ascribed to boosted formation of reactive oxygen species (ROS), increased selectivity of intermediates, and promoted ring-opening and mineralization rate. Combining theoretical simulation and experimental characterization, the results reveal that the O 2 and H 2 O molecules tend to be adsorbed on the cubic STO, which boosts the formation of ROS. Also, highly selective formation of intermediate (benzoic acid) has been realized to accelerate ring-open and mineralization process as evidenced by the smooth conversion of STO as indicated by Gibbs free energy. This work provides new perspectives on the understanding of relationship between intrinsic structure and photocatalytic performance.
研究领域:
材料科学
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环境科学
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催化
·
化学工程
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DOI
高影响因子
Inorganic Chemistry Frontiers
·
2022
·Vol. 10
·期 4
·1112-1118
·
IF 7.779
Ming-Shu Zhang,Bin-Wen Liu,Xiao-Ming Jiang,Guo-Cong Guo
Two quaternary phosphides AIn3Si4P9 (A = Ca, 1; Sr, 2) belonging to the non-centrosymmetric space group P41212 are discovered and synthesized through the solid-state method for the first time. They present extraordinary double-helix frameworks composed of corner-shared tetrahedral [InP4] and [SiP4] units. Although compounds 1 and 2 have undesirable band gaps (1.25 and 1.15 eV), their extremely low thermal expansion coefficients (∼10−6) result in high laser-induced damage thresholds approximately seven times that of benchmark AgGaS2 under a 2050 nm laser. Moreover, both compounds show weak second-harmonic generation intensities primarily caused by Kleinman forbidden nonlinear optical coefficients. Theoretical calculations further reveal that the electron transitions mainly originated from the tetrahedral [InP4] and [SiP4] units.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Lisha Zhang,Yudong Ji,Weidong Li,Bing Zhang,Qiang Ma,Bowen Qin,Yilei Zhang,Dan Yue,Zhenling Wang
Lanthanide ions-doped fluoride nanocrystals have excellent application prospect. However, low photoluminescence quantum yield (PLQY) is usually along with lanthanide ions-doped fluoride nanocrystals owing to their low molar absorptivity and narrow absorption band . In order to increase the absorption cross section of Ln 3+ in fluoride nanocrystals, a facile synthesis strategy to enhance luminescence of AF 2 : Ln 3+ (A = Ca, Sr; Ln = Eu, Tb) by the use of carbon dots (CDs) has been developed in this work. A series of characterizations including TEM , XRD , FTIR and XPS demonstrated that the CDs have been successfully combined with the surface of AF 2 : Ln 3+ nanocrystals. The combination of CDs has little influence on the microstructure and phase structure of AF 2 : Ln 3+ , and CDs@AF 2 : Ln 3+ nanocrystals have uniform and regular shape with cubic phase. CDs are used as a broadband sensitizer and lead to the broadband excitation of Ln 3+ , resulting in the enhancement around 10-fold of Ln 3+ luminescence emission in AF 2 : Ln 3+ nanocrystals after CDs combination. The corresponding PLQY increases almost three times, and the luminescence enhancement mechanism by combining CDs is proposed. In addition, the CDs@AF 2 : Ln 3+ nanocrystals are used to prepare CDs@AF 2 : Ln 3+ /PVA films, which exhibits excellent luminescence properties under the excitation of UV light . This work provides a superior method for enhancing the luminescence properties of lanthanide ions-doped nanocomposites and demonstrates practical potential as promising candidates for light-converting thin films .
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
ACTA MATERIALIA
·
2022
·
IF 9.209
Qian Liu,Ke-Feng Liu,Qi-Qi Wang,Xiao-Cun Liu,Fang Yu,Jian Liu,Yuan-Yuan Su,Sheng-Qing Xia
In this report, for the first time TiNiSi-type Zintl phases with the nominal formulae of ALiSb (A = Ca, Sr, Eu, Yb) were systematically investigated on their thermoelectric properties. The results indicated that ALiSb Zintl phases possessed intrinsically low lattice thermal conductivity despite the simple structure. In combination of thorough crystallographic and theoretical investigation, rattling-like scattering behavior originating from the Li atoms was suggested. As a result, the pristine ALiSb materials featured decent zT values of 0.4–0.7 at 823 K. With the electrical and thermal transport properties further optimized by configuring the solid solutions such as Sr 0.8 Eu 0.2 LiSb, the material approached a maximum zT up to 1.2 at the same temperature. These breakthroughs are distinct from the previous knowledge that low thermal conductivity in Zintl phases is usually realized through complex crystal structures, and for compounds with simple structures such as the TiNiSi type it is common to have poor thermoelectric performance. Owing to such a rattling-like scattering behavior, now light-element containing Zintl phases can be a promising resource for thermoelectric considerations as well. The mechanism is surely interesting and worth of in-depth investigation.
研究领域:
材料科学
·
热电材料
·
固体化学
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晶体学
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能源材料
✓ 已验证
DOI
高影响因子
Advanced Energy Materials
·
2022
·Vol. 12
·期 22
·2200392
·
IF 29.698
Peng Zhong,Kazuaki Toyoura,Lulu Jiang,Lubing Chen,Sara Adeeba Ismail,Naoyuki Hatada,Truls Norby,Donglin Han
A significant hydration and protonic conduction in La 2 NiO 4+ δ -based Ruddlesden–Popper (RP) oxides will enable their use as positrode materials in proton ceramic electrochemical cells (PCECs). Unlike perovskite electrolytes and positrode materials, where protons reside and jump on regular oxide ions, RP oxides such as La 2 NiO 4+ δ may contain oxygen interstitials and offer the possibility that protons locate on and migrate by help of these, suggesting a mechanism by which positrodes may operate by triple conduction. Here, theoretical calculations that support proton migration between interstitial oxide ions in the rock-salt layer via unshared oxide ions in the perovskite layer are reported. Furthermore, water contents of pristine La 2 NiO 4+ δ and La 2- x A x NiO 4+ δ ( A = Ca, Sr, Ba) are reported, showing that hydration increases with the level and basicity of the dopant. Hebb-Wagner blocking electrode measurements show significant partial protonic conductivity in all samples. The effects of doping on hydration and of p H 2 O on the p-type conductivity suggest that protons reside primarily on structural oxide ion, but a role of interstitial oxide ions for dissolution and migration of protons cannot be ruled out in cases with oxygen excess. The results are instructive for further studies and optimization of RP oxides as potential positrode materials for PCECs.
研究领域:
材料科学
·
电化学
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2017
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IF 3.582
Lingwei Lu,Shuang Ni,Gang Liu,Xiaoxiang Xu
The crystal structure of a photocatalyst generally plays a pivotal role in its electronic structure and catalytic properties . In this work, we synthesized a series of La/Cr co-doped perovskite compounds ATiO 3 (M = Ca, Sr and Ba) via a hydrothermal method . Their optical properties and photocatalytic activities were systematically explored from the viewpoint of their dependence on structural variations, i.e. impact of bond length and bond angles. Our results show that although La/Cr co-doping helps to improve the visible light absorption and photocatalytic activity of these wide band gap semiconductors , their light absorbance and catalytic performance are strongly governed by the Ti O bond length and Ti O Ti bond angle. A long Ti O bond and deviation of Ti O Ti bond angle away from 180° deteriorate the visible light absorption and photocatalytic activity. The best photocatalytic activity belongs to Sr 0.9 La 0.1 Ti 0.9 Cr 0.1 O 3 with an average hydrogen production rate ∼2.88 μmol/h under visible light illumination (λ ≥ 400 nm), corresponding to apparent quantum efficiency ∼ 0.07%. This study highlights an effective way in tailoring the light absorption and photocatalytic properties of perovskite compounds by modifying cations in the A site.
研究领域:
材料科学
·
物理化学
·
能源化学
·
无机化学
·
光催化
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Chenxiao Wang,Kui Liu,Yinghao Wu,Guangjun Zhang,Xuelian Li,Jiaxin Wu,Ruili Sun,Ting Chen,Lang Xu,Shaorong Wang
A-site doping with Ca 2+ , Sr 2+ for the cobalt-free BaFeO 3-δ -based cathode materials for proton-conducting ceramic fuel cells (PCFCs) is studied. The composite Ba 0·8 Ca 0·2 FeO 3-δ (BCF0.2)-BaZr 0.1 Ce 0·7 Y 0.1 Yb 0.1 O 3-δ (BZCYYb) and Ba 0·8 Sr 0·2 FeO 3-δ (BSF0.2)-BZCYYb electrode show polarization resistance (R p ) of 0.156 Ω cm 2 and 0.308 Ω cm 2 at 700 °C, respectively. It is found that the Ca or Sr doping not only benefits oxygen vacancy formation and ion migration but also optimizes the surface oxygen reduction reaction (ORR) process. The density functional theory (DFT) calculations show that the Gibbs energies of *OOH and *OH intermediates are decreased, indicating an enhanced surface ORR. The PCFC with BCF0.2-BZCYYb composite cathode achieves the maximum power density of 299.75 mW cm −2 at 700 °C and shows good stability at 650 °C for 65 h under a constant voltage of 0.75 V. These findings suggest that the BCF0.2-BZCYYb has the potential to serve as cobalt-free cathode materials for PCFCs.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2025
·
IF 6.2
Xiaohua Li,Zhufeng Liu,Shanshan Shao,Yongbo Yu,Weicheng Wang,Tianrui Sun,Shiliang Wu
Steam reforming of bio-oil is a promising technology for the industrial-scale conversion of biomass into hydrogen energy, in which the catalyst plays the crucial role. This study proposes a Ni-Ca-Al-Ce-O catalyst, prepared by CaO loading onto Ni/CeO 2 ·Al 2 O 3 , and tested in the two-stage adsorption-enhanced reforming of biomass pyrolysis oil for hydrogen production. The effects of carrier type and Ni loading on the physicochemical properties of the Ca modified Ni-based reforming catalyst and its reforming performance were investigated, and its reusability was tested finally. The results revealed that more Ni metal active sites are available on CeO 2 ·Al 2 O 3 compared to biochar as carrier. However, side reactions such as ketonization were significantly promoted due to the metal oxides in red mud (RM), resulting in a large amount of methane as a by-product over the Ni/RM catalyst. When Ca additive introduced on the well selected Ni/CeO 2 ·Al 2 O 3 , the selectivity of hydrogen in the reforming gas was enhanced. Meanwhile, more spinel NiAl 2 O 4 was formed due to the interaction between NiO and Al 2 O 3 , which enhanced the stability and activity of the Ni-Ca-Al-Ce-O catalyst. With a Ca/Al ratio of 1:1, Ni was more uniformly dispersed, and the yield and selectivity of hydrogen reached 73.35 % and 76.90 %. In the reusability tests, the yield of hydrogen remained above 60 % after six runs, which was superior to that of similar reforming catalysts, suggesting that the proposed Ni-Ca-Al-Ce-O catalyst is reliable in terms of reusability.
研究领域:
能源化学
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2020
·
IF 9.567
Dongjie Liu,Xiaohan Yun,Peipei Dang,Hongzhou Lian,Mengmeng Shang,Guogang Li,Jun Lin
Recently, there has been growing interest in developing Bi3+-activated luminescence materials for optoelectronic applications. Herein, new yellow/orange-emitting ABZn2Ga2O7:Bi3+ (ABZGO, A = Ca, Sr; B = Ba, Sr) phosphors with tunable optical properties are synthesized by an alkaline earth cation substitution. When Sr2+ substitutes Ca2+ and Ba2+, the excitation wavelength has a red shift from 325 to 363 nm, matching well with the n-UV chip based white light-emitting diodes (WLEDs). CaBaZn2Ga2O7:0.01Bi3+ (CBZGO:0.01Bi3+) exhibits two evident emission peaks at 570 and 393 nm originating from the respective occupation of Ca and Ba sites by Bi3+ ions. The optical tuning of the CBZGO:Bi3+ phosphor is achieved by changing the Bi3+ doping content and excitation wavelength based on the selected site occupation. Differently, both SrBaZn2Ga2O7:0.01Bi3+ (SBZGO:0.01Bi3+) and Sr2Zn2Ga2O7:0.01Bi3+ (SZGO:0.01Bi3+) phosphors exhibit a single broad emission band, peaking at 600 and 577 nm, respectively. Two different Bi3+ sites are also verified respectively in SBZGO and SZGO hosts by the Gaussian fitting of the asymmetric PL spectra and lifetime analysis. The different luminescence behaviors of ABZGO:0.01Bi3+ phosphors should be ascribed to the synergistic effect of the centroid shift, crystal-field splitting, and Stokes shift. Moreover, the temperature-dependent PL spectra reveal that cation substitutions of Sr2+ for Ca2+ and Ba2+ can efficiently improve the thermal stability of ABZGO:0.01Bi3+ phosphors. In view of different thermal responses to various temperatures for two emission peaks of the CBZGO:0.01Bi3+ phosphor, an optical thermometer is designed and has a good relative sensitivity (Sr = 1.453% K–1) at 298 K. Finally, a WLED with CRI = 97.9 and CCT = 3932 K is obtained by combining SZGO:0.01Bi3+ and BAM:Eu2+ phosphors with a 370 nm n-UV chip, demonstrating that SZGO:0.01Bi3+ is an excellent yellow-orange-emitting phosphor for n-UV WLED devices. This work stimulates the exploration of optical tuning by cation substitution to obtain remarkable luminescence materials for optical temperature sensing and WLED applications.
研究领域:
材料科学
·
光电子学
·
发光与荧光粉
·
固态照明
·
温度传感
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Jingxin Liu,Wenjuan Zhang,Meng Mei,Teng Wang,Si Chen,Jinping Li
Arsenic (As) contamination in water is an international environmental issue. Biochar adsorption is often considered a promising way for removing As from contaminated water due to its low-cost and environmental friendliness. However, the poor adsorption capacity limits the application of pristine biochar, and various modification methods are proposed to improve this shortcoming, which inevitably brings some new environmental problems. Herein, a pristine Ca-rich biochar with excellent As adsorption performance was prepared through one-step pyrolysis of food waste digestate. The results demonstrated that the biochar obtained at 800 °C (CDBC8) exhibited higher specific surface area and absorption capacity of As than biochars prepared at other temperatures, with the maximum As adsorption capacity of 69.03 mg/g, which was much higher than most previously reported pristine biochars and even some modified biochars. This is attributed to the considerable portions of CaO and carbon in CDBC8. The adsorption process was best modeled by Langmuir model and the pseudo-second-order kinetic model. Furthermore, the removal mechanism of As was discussed in-depth. The complexation, precipitation, oxidation, and electrostatic attraction participated in the adsorption, and their contributions were significantly impacted by the pH of the solution. This work presents the great potential of this Ca-rich biochar for wastewater remediation, and also provides a feasible way for the rational utilization of food waste digestate.
研究领域:
环境科学
·
水处理
·
吸附技术
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废物资源化
·
污染物修复
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）