MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 6
·1-8
·
IF 5.479
Zhang Yu,Xu Mengjiao,Gao Pan,Gao Wenkai,Bian Zhenfeng,Jia Nengqin
A photoelectrochemical (PEC) method was developed for the determination of dopamine. It is making use of a composite prepared from gold nanoparticles and TiO 2 (type P25) and placed on a fluorine-doped tin oxide (FTO) electrode. The composites are used for photoelectrical detection with improved electron transfer efficiency for photoproduction and with improved photoelectrical conversion efficiency. This is due to the excellent electrical conductivity and surface plasmon resonance absorption by gold nanoparticles, and also by the photocatalytic effect of TiO 2 . Dopamine binds easily to the surface of the composites and acts as an electron donor. This electrode gives a strongly enhanced photocurrent which increases linearly in the 0.1 to 100 μM dopamine concentration range and has a 23 nM detection limit (at S/ N = 3). The electrode was operated over 15 cycles of light-on and light-off states every 20 s under visible-light illumination, and the sensor indicates good stability. In addition, it is selective over several possible interferents including uric acid, L-cysteine, glutathione, ascorbic acid and glucose.
A new gold/P25 composite-based photoelectrochemical sensing scheme for dopamine is described. Under visible light irradiation, the photocurrent response is increased with the increasing concentration of dopamine (DA).
研究领域:
分析化学
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生物医学工程
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材料科学
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DOI
PubMed
高影响因子
Nature Communications
·
2022
·Vol. 13
·期 1
·1-12
·
IF 17.694
Guo Yalin,Huang Yike,Zeng Bin,Han Bing,AKRI Mohcin,Shi Ming,Zhao Yue,Li Qinghe,Su Yang,Li Lin,Jiang Qike,Cui Yi-Tao,Li Lei,Li Rengui,Qiao Botao,Zhang Tao
Semi-hydrogenation of acetylene in excess ethylene is a key industrial process for ethylene purification. Supported Pd catalysts have attracted most attention due to their superior intrinsic activity but often suffer from low selectivity. Pd single-atom catalysts (SACs) are promising to significantly improve the selectivity, but the activity needs to be improved and the feasible preparation of Pd SACs remains a grand challenge. Here, we report a simple strategy to construct Pd 1 /TiO 2 SACs by selectively encapsulating the co-existed small amount of Pd nanoclusters/nanoparticles based on their different strong metal-support interaction (SMSI) occurrence conditions. In addition, photo-thermo catalysis has been applied to this process where a much-improved catalytic activity was obtained. Detailed characterization combined with DFT calculation suggests that photo-induced electrons transferred from TiO 2 to the adjacent Pd atoms facilitate the activation of acetylene. This work offers an opportunity to develop highly stable Pd SACs for efficient catalytic semi-hydrogenation process.
研究领域:
化学工程
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催化科学
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产品关联
DOI
PubMed
高影响因子
ChemCatChem
·
2023
·Vol. 15
·期 7
·e202201687
·
IF 4.5
Wenjing Xu,Yingying Cheng,Jing Hou,Peng Kang
Graphical Mesoporous TiO 2 spheres with large specific surface area were synthesized by a simple two-step method for the electrocatalytic reduction of oxalic acid. The maximum Faradaic efficiency for glycolic acid reached 73.9 % at −0.5 V at ambient temperature, exceeding most recently reported results. Reducing oxalic acid to glycolic acid electrochemically remains a significant challenge due to the high overpotential and low selectivity and stability. This study uses mesoporous TiO 2 spheres of anatase phase as catalysts to reduce oxalic acid to glycolic acid with low overpotential. The maximum Faradaic efficiency of glycolic acid reaches 73.9 % at −0.5 V vs RHE. The mesoporous structure not only increases the specific surface area, but also limits the escape of intermediate glyoxalic acid from the catalyst surface due to the space-limiting effect of the mesoporous channel, such that oxalic acid can be deeply reduced to glycolic acid. Moreover, a mechanism for oxalic acid reduction is proposed, and the Ti 3+ /Ti 4+ redox pair plays an important role in the reduction of oxalic acid.
研究领域:
材料科学
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电化学
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DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Peng Wang,Chengming Yu,Jiale Huang,Zhudan Jiang,Xinyu Jiang,Shanglin Xiang,Dongyu Cai
Developing an efficient photocatalyst with good recyclability is vital for the sustainability and affordability of photocatalytic technology in the treatment of wastewater. This work demonstrates a facile route for realizing robust TiO 2 @Ti 3 C 2 T x fibers with exceptional photocatalytic capability and recyclability. In this route, an alkalization/de-alkalization process was developed to treat a concentrated Ti 3 C 2 T x suspension known as MXene sediment, followed by a wet spinning process. The pretreatment of Ti 3 C 2 T x suspensions promoted the expansion of the d-spacing of stacked Ti 3 C 2 T x layers in the microfibers. It was found that this was beneficial for increasing the population of TiO 2 nanoparticles grown from Ti 3 C 2 T x layers. The calcination of these fibers was systematically investigated to optimize the photocatalytic performance of TiO 2 @Ti 3 C 2 T x fibers. Thanks to the TiO 2 nanoparticles, the resulting fibrous photocatalysts not only enabled the fast degradation of RhB dyes but also exhibited excellent recoverability from water.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Qitong Xue,Jiaying Xing,Jianjun Chen,Jinxing Mi,Jianqiang Shi,Yao Wang,Junhua Li,Zhiming Liu
V 2 O 5 /TiO 2 has been wide used in the selective catalytic reduction of NO x by NH 3 (NH 3 -SCR). However, the poisoning mechanism of thallium (Tl) on the catalytic performance of commercial V 2 O 5 /TiO 2 catalyst has remained unclear. Herein, we have systematically investigated the poisoning effect of Tl based on the different characterizations and DFT calculations. It was found that the strong interaction between V and Tl exists, resulting in the transformation of V from monomeric VO x to polymeric and crystalline VO x , the formation of V-O-Tl species, a decrease in the active V 5+ sites, and the inhibition of the adsorption and activation of NH 3 on both Brønsted and Lewis acid sites. Mechanistic studies further confirmed that inactive nitrate intermediate species gradually accumulated over V 2 O 5 /TiO 2 catalyst surface due to the presence of Tl. A combination of factors ultimately led to the deactivation of the V 2 O 5 /TiO 2 catalyst. This study unveils the poisoning mechanism of Tl on V-based catalysts and shed light on the design of Tl-tolerant NH 3 -SCR catalysts.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2023
·
IF 11.2
Hongxu Liu,Junhao Xie,Ziyi Hu,Jingxuan Zhao,Ruijia Wang,Yuchao Qi,Shulin Sun
This work obtained separation membranes with UV-cleaning performance by adding TiO 2 -g-CS/CNTs photocatalyst to the PVDF . The positively charged chitosan (CS) and negatively charged carboxylic carbon nanotube (CNTs-COOH) can be self-assembled into the bilayer structure on the surface of TiO 2 particles through electrostatic attraction. The presence of many hydrophilic groups in CS and CNTs-COOH significantly improves the hydrophilicity of TiO 2 -g-CS/CNTs-PVDF membrane, and helps TiO 2 to be uniformly dispersed on the upper surface. TiO 2 -g-CS/CNTs promote the change of pore structure and expand the flux of the modified membrane to 4.5 times that of pure PVDF . Zeta potential demonstrates that the TiO 2 -g-CS particles successfully attracted CNTs in the PVDF matrix, and the membrane surface was still positively charged. Thus, the combined effect of the positively charged TiO 2 -g-CS and the highly adsorbed CNTs enhanced the retention of the contaminants. More importantly, there is a charge transfer between the grafted CS and TiO 2 interface to obtain a broader light absorption band. The excitation carriers provided by CNTs significantly contribute to the photocatalytic performance after transfer between TiO 2 and CS; thus, TiO 2 -g-CS/CNTs-PVDF produces higher photocatalytic activity for dye molecules (degradation rate > 97 %).
研究领域:
材料科学
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环境工程
·
化学工程
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产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2023
·
IF 7.2
Xiaoyun Ye,Hangyu Zhong,Yumei Zhang,Yuping Wu,Shuguang Cai,Song Chen,Lian Ma,Qianting Wang
In this work, a ternary Ti 3 C 2 /TiO 2 /SrTiO 3 composite with heterogeneous network structure was prepared by two-step in situ hydrothermal synthesis method, which mainly involved the growth of TiO 2 nanosheets and fibrous SrTiO 3 sequentially on the Ti 3 C 2 substrate using the Ti source inherent in Ti 3 C 2 as the reaction site. The Ti 3 C 2 /TiO 2 /SrTiO 3 heterojunction exhibited enhanced photocatalytic hydrogen evolution activity. When the doping amount of SrTiO 3 was 5 wt%, the hydrogen evolution rate of 5MTS under full solar irradiation reached 14322.6 μmol·g −1 ·h −1 , which was 10.6 times the rate of the Ti 3 C 2 /TiO 2 composite without modified SrTiO 3 . Meanwhile, the 5MTS composites showed good stability in the photocatalytic hydrogen evolution cycle test. The enhanced activity and recyclability are mainly attributed to the strong light absorption ability, fast separation of photogenerated electron-hole pairs, and abundant catalytic active sites. In addition, the synthesis method utilizing an intrinsic Ti source also enhances the interfacial contact between Ti 3 C 2 , TiO 2 , and SrTiO 3 . This study provides an effective reference for the construction of perovskite-based or Ti 3 C 2 co-catalyzed heterostructures and their application for the conversion of solar power to hydrogen energy .
研究领域:
材料科学
·
能源科学
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Weichao Wang,Gu Liu,Liuying Wang,Chaoqun Ge,Long Wang,Bin Wang,Jie Huang
The advancement of absorption materials and coating preparation technology is crucial to address the challenges posed by electromagnetic interference and pollution in high-temperature extreme environments. Here, by using a granulation and plasma spraying strategy, we successfully fabricated a series of La 0.8 Sr 0.2 MnO 3 /Al 2 O 3 –13%TiO 2 (LSMO/AT13) high-temperature microwave absorption coatings that have excellent dielectric properties and extremely thermal stability. The results showed that the LSMO/AT13 coatings exhibited remarkable oxidation resistance , withstanding high-temperature aerobic environments of up to 1000 °C. Based on the temperature-dependent permittivity of the coatings, the establishment process of polarization and the transformation of loss mechanism were observed and explained. With the increase of temperature, the main dielectric loss mechanism of the coatings transitions from polarization loss to conductive loss. Thanks to the coordinated effects of impedance and loss, the coatings are capable of effectively absorbing microwave over a wide temperature range. When the LSMO content was 30 wt% and the thickness was 1.9 mm, the effective bandwidth ranged from 1.7 GHz to 2.4 GHz at temperatures below 773 K. This study demonstrates the promising application of LSMO/AT13 microwave absorption coatings for ultra-high temperature environment, and provides a reference for the design and optimization of high-temperature microwave absorption coatings.
研究领域:
材料科学
·
电磁学
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产品关联
DOI
高影响因子
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
·
2024
·
IF 4.7
Li-guo ZHU,Chong-lin BAI,Ling-xin KONG,Bin YANG,Bao-qiang XU
To reduce the production cost of titanium, a new method for direct preparation of low-oxygen titanium powder by the magnesiothermic reduction of TiO 2 with the assistance of a MgCl 2 -HoCl 3 molten salt was proposed. Thermodynamic calculations showed that the magnesiothermic reduction of TiO 2 was feasible. However, hindrance of the reduction reaction by the reduction by-product of MgO resulted in a considerably high O concentration in the titanium powder. The addition of HoCl 3 to the system significantly reduces the activity of MgO to produce low-oxygen titanium powder. Thermochemical deoxidation and reduction experiments were conducted with MgCl 2 -HoCl 3 molten salt in the temperature range of 1023-1273 K. The results showed that titanium powder with oxygen concentration (mass fraction) below 5.00×10 -4 can be prepared at the Mg-MgCl 2 -HoOCl-HoCl 3 equilibrium.
研究领域:
材料科学
·
冶金工程
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产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2020
·Vol. 150
·期 7
·1890-1897
·
IF 2.482
Zhou Na,Yan Ruiyao,Pan Yanlin,Fang Xue-Qian
The fast recombination of photogenerated electrons and holes in the pure TiO 2 leads to a low photocatalytic efficiency in hydrogen generation or solar energy conversion. Noble metal nanoparticles have been used to combine with TiO 2 for effective photocatalysis. Herein, Au@Ag@TiO 2 nanorods (NRs) with core–shell structure have been prepared by hydrolysis the precursor of titanium in acid environment. UV light–driven H 2 generation rate of Au@Ag@TiO 2 samples demonstrated 14 times enhancement compared to P25 TiO 2 at the same experimental conditions. The improved photocatalytic performance was due to the charge transfer from the conduction band of excited TiO 2 to Au@Ag NRs leading to effective separation of electron–hole pairs. This mechanism has been proved by transient absorption spectroscopy and photo-electrochemical (PEC) measurements. The time resolved photocurrents of P25 TiO 2 NPs is ~ 13 times higher that of Au@Ag@TiO 2 , indicating that a fraction of the photogenerated electrons of TiO 2 driven by UV light transfer to Au@Ag nanocores instead of transporting entirely to the ITO substrates. The ultrafast transient absorption and pump-probe measurements demonstrated a faster decay in Au@Ag@TiO 2 NRs compared to pure TiO 2 system, indicating that the photogenerated electron–hole recombination in TiO 2 is substantially suppressed by Au@Ag@TiO 2 NRs attributed to the effective trapping of the photogenerated electrons by the Au@Ag cores. Graphic Abstract Au@Ag@TiO 2 nanocomposites with core-shell structure have been prepared and its UV light–driven H 2 generation rate has been demonstrated 14 times enhancement compared to P25 TiO 2 at the same experimental conditions. The improved photocatalytic performance was due to the charge transfer, which has been proved by photocurrent measurement and the ultrafast transient absorption and pump-probe measurements.
研究领域:
材料科学
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纳米技术
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光化学
·
催化
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产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Zengsheng Guo,Hao Wu,Ming Li,Tao Tang,Jianfeng Wen,Xinyu Li
Reducing the direct recombination of the photogenerated electron-hole pairs in a photocatalytic system is important to improve the photocatalytic efficiency. Transferring the photogenerated carriers to other adsorbates is a usual way to reduce the direct recombination probability. By synthesizing p-type phosphorus-doped graphene quantum dots (P-GQDs) to form p-n junctions with n-type TiO 2 nanocomposites, the photogenerated holes of TiO 2 can be effectively transferred to P-GQDs, thus the direct carrier recombination of TiO 2 is decreased, resulting in the conspicuous improvement of the Methyl Orange (MO) photodegradation efficiency to 95.5% in 14 min. This work provides a new type of p-n junction in highly efficient photodegradation system.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2016
·Vol. 6
·期 22
·7967-7975
·
IF 5.287
Jie Zhao,Yun Wang,Yingxuan Li,Xiu Yue,Chuanyi Wang
CeO2 is a basic promoter for CO2 photoreduction with H2O over TiO2-based catalysts, but there is still a lack of insight into the interaction of CeO2 with different TiO2 polymorphs and its effect on CO2 photoreduction. In this study, pure anatase, brookite, and rutile TiO2 and their respective hybrids with CeO2 were prepared, and their structural properties, optical properties, interfacial interaction and activity for CO2 photoreduction were systematically studied. The addition of CeO2 improved the activity for CO2 photoreduction under simulated sunlight irradiation, but the improvement depends on the phases of the TiO2. X-ray diffraction, macro-Raman spectroscopic and electron paramagnetic resonance measurements confirm the presence of Ti defects at the CeO2–rutile interfaces, implying a relatively strong interaction between CeO2 and rutile, which is beneficial for the interfacial separation of photogenerated charge carriers. As a result, CeO2/rutile shows the best enhancement of CO2 photoreduction among the studied CeO2/TiO2 systems. Moreover, different paramagnetic species were detected in the three TiO2 polymorphs. The O− radical anion in the anatase lattice could be oxidized to produce Ti3+ under UV-light irradiation, whereas the O2− radical anion on the surface of brookite TiO2 might retard CO production.
研究领域:
材料科学
·
催化化学
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DOI
高影响因子
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