查找使用阿拉丁产品的科研文献

Batch and Continuous-Flow Preparation of Biomass-Derived Furfural Acetals over a TiO2 Nanoparticle-Exfoliated Montmorillonite Composite Catalyst

Bo Zhou,Fan Song,Xinyue Ma,Lijun Wang

Graphical The batch is back : A scalable green catalyst system based on a TiO 2 nanoparticle–exfoliated montmorillonite composite catalyst with hard Lewis acid sites and abundant accessible Brønsted acid sites is developed for the rapid preparation of furfural acetals, which are a promising biofuel with high octane value, high calorific value, and high oxidation resistance. Furfural acetals with high octane value, high calorific value and high oxidation resistance are considered promising biofuels or fuel precursors with huge potential demand. However, there are few studies on efficient scalable catalyst systems, including continuous-flow catalyst systems, for their preparation. In this work, TiO 2 nanoparticles supported on exfoliated montmorillonite, with strong Lewis acid sites and abundant accessible Brønsted acid sites, is used to catalyze the acetalization reactions of biomass-derived furfural and alcohols. Low dosage of the catalyst made the reaction reach equilibrium in a very short time (TOF=690–1305 min −1 ) at room temperature with the acetal as the only product. In continuous-flow reactions, the catalyst showed a stable product output with conversion close to that for the batch reaction with a short catalyst-reactant contact time of 150 s. Contrast experiments revealed that both Lewis and Brønsted acid sites on the catalyst were indispensable for maximizing the catalytic performance, and simultaneously activating both furfural and alcohol on the adjacent Lewis and Brønsted acid sites was proposed to be responsible for the high catalytic performance.

A photoelectrochemical sensor based on Z-Scheme TiO2@Au@CdS and molecularly imprinted polymer for uric acid detection

Zhao Junhong,Cheng Jing,Sun Yudong,Liu Jiang,Chen Wen,Xu Yi,Yang Jiao,Li Yingchun

A novel photoelectrochemical (PEC) sensor based on “Z-scheme” TiO 2 @Au@CdS and molecularly imprinted polymer (MIP) was developed for the non-invasive detection of uric acid (UA). The “Z-scheme” material, consisting of an electron-transfer system (Au) and two isolated photochemical systems (CdS, TiO 2 ), was synthesized by chemical deposition method and it worked as a substrate for electro-polymerization of MIP. Due to the high photoelectric conversion efficiency provided by TiO 2 @Au@CdS and specific imprinting effect afforded by MIP, the sensor displayed desirable sensing performance with the merits of sensitivity, selectivity, repeatability, and stability. The linear range for UA detection is from 1 nM to 9 μM with the detection limit of 0.3 nM (S/ N  = 3). Moreover, the assay was successfully utilized to measure UA in human tears and offered a reliable result. The incorporation of MIP and “Z-scheme” material into a PEC sensor system is expected to provide a promising strategy for detecting other small molecules. Graphical abstract

Highly efficient purification of emerging pollutants and bacteria in natural water by g-C3N4-sheltered fibers containing TiO2

Qinxue Xiong,Yi Chen,Tiefeng Xu,Zhexin Zhu,Wenxing Chen,Wangyang Lu

In this work, a flexible photocatalytic material (TiO 2 @g-C 3 N 4 -cotton) was obtained using modified graphitic carbon nitride (g-C 3 N 4 -CONH-KH550) for the a connection between the natural cotton supports and titanium dioxide (TiO 2 ) successively. Under the visible light, a valid photocatalytic activity was observed in the degradation of sulfaquinoxaline (SQX) and thiamethoxam. According to the support stability tests and the UV accelerated aging tests, g-C 3 N 4 -CONH-KH550 could shelter the supports with TiO 2 from the oxidation attack by hydroxyl radicals (•OH) generated. The investigation of antibacterial activity showed efficient inactivation of both Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ). Therefore, TiO 2 @g-C 3 N 4 -cotton showed stronger mechanical performance and much longer lifetime compared with TiO 2 @cotton. The degradation products and processes of substrates were investigated. This paper provides a new idea about the construction of an efficient and stable supported photocatalytic material.

TiO2@MOF Photocatalyst for the Synergetic Oxidation of Microcystin-LR and Reduction of Cr(VI) in Aqueous Media

Yarui Wang,Wanchao Yu,Fanglan Geng,Lixia Zhao,Yawei Wang

The coexistence of pollutants presents a great challenge to the implementation of photocatalysts. In this work, a novel MIL-101(Fe)/TiO2composite prepared by in situ growth of MIL-101(Fe) on TiO2was developed for the synergetic oxidation of MC-LR and Cr(VI) reduction. The heterojunction material shows elevated photocatalytic behavior under ultraviolet compared with the unary pollutant system. Furthermore, quenching experiments and electron spin resonance confirm that the enhanced photodegradation behavior is related to the synergistic effect between the photocatalytic reduction and oxidation process, in which MC-LR consumes the holes and Cr(VI) captures electrons, followed by efficient charge separation through the conventional double-transfer mechanism between MIL-101(Fe) and TiO2. This investigation provides a deeper understanding of the construction of MOFs/semiconductor heterojunctions for the pollutants removal in multi-component contaminants system.Keywords:TiO2@MOF photocatalyst;Cr(VI);microcystin-LR;synergetic removal

Synergistically boosting sulfamerazine degradation via activation of peroxydisulfate by photocatalysis of Bi2O3-TiO2/PAC under visible light irradiation

Jia-qi Li,Zhi-wei Zhou,Xing Li,Yan-ling Yang,Jing-feng Gao,Rui Yu,Hui-ping Wang,Nan Wang

Photocatalysis-activated sulfate-radical advanced oxidation process (SR-AOP) is an effective approach to remove organic micropollutants from water. Here, we tested a photocatalysis-activated SR-AOP in which peroxydisulfate (PDS) was activated by composites of Bi 2 O 3 -TiO 2 photocatalyst supported onto commercial powdered activated carbon (Bi 2 O 3 -TiO 2 /PAC) under visible light irradiation. This “Vis-Cata-PDS” treatment exhibited outstanding degradation performance (97.96% removal) towards sulfamerazine (SMZ) following optimized reaction conditions of 0.1 g/L Bi 2 O 3 -TiO 2 /PAC and 0.1 g/L PDS at pH of 7. Synergistic effects were observed between the visible-light photocatalytic activation of PDS via direct electron transfer and nonradical PDS activation over pristine PAC within Bi 2 O 3 -TiO 2 /PAC. Both active radicals (SO 4 ·− , h + , ·O 2 − ) and nonradical singlet oxygen ( 1 O 2 ) and the mediated electron transfer of pristine PAC within Bi 2 O 3 -TiO 2 /PAC were contributed to SMZ degradation. Based on intermediates identified by Liquid Chromatograph-Mass Spectrometer (LC-MS) combined with density functional theory (DFT) calculations, three degradation pathways were proposed and that were mostly attributed to SO 2 extrusion/Smiles-type rearrangement and S-N bond cleavage, and toxicity of intermediates were effectively alleviated. An inhibitory effect on SMZ degradation was observed for presence of HCO 3 − , whereas presence of SO 4 2− was less inhibitory and Cl − had no effect. The Bi 2 O 3 -TiO 2 /PAC composite displayed excellent reusability and stability, and it was effective towards a number of tested micropollutants (sulfadiazine, sulfamethoxazole, ciprofloxacin, bisphenol A and methyl orange) and in real water matrixes. This work offers deep insights into the nonradical oxidation mechanism and application of Vis-Cata-PDS over a Bi 2 O 3 -TiO 2 /PAC composite for removal of organic micropollutants.

High-rate and ultralong-life Mg–Li hybrid batteries based on highly pseudocapacitive dual-phase TiO2 nanosheet cathodes

Mewin Vincent,Venkata Sai Avvaru,Miguel Castillo Rodríguez,Maciej Haranczyk,Vinodkumar Etacheri

Although Mg–Li hybrid batteries are proposed as an alternative to Mg-batteries, the lack of dual-ion compatible cathodes are limiting their practical application. Herein, we report a high-rate and ultralong-life Mg–Li hybrid battery based on a dual-phase TiO 2 cathode. Highly pseudocapacitive hierarchical two-dimensional TiO 2 consists of anatase (60%) and bronze (40%) nanocrystallites forming interfaces due to crystal structure mismatch. This dual-phase hierarchical cathode exhibits excellent pseudocapacitance (up to 92%), specific capacities (235 mAh/g @ 25 mA/g), rate performance (120 mAh/g @ 1A/g) cycling stability (~87% after 3000 cycles @ 1A/g) and coulombic efficiency (~100%). These results are vastly superior to the previously reported values for TiO 2 based Mg–Li hybrid battery cathodes. Only minimal structural changes are observed during the charge-discharge of two-dimensional TiO 2 electrode. Outstanding electrochemical performance of dual-phase TiO 2 nanosheet cathode is attributed to the superior pseudocapacitive Mg/Li-ion diffusion through nanointerfaces between anatase and bronze crystallites . While other structural features such as 2D-morphology, ultrathin nature, mesoporosity, and high surface area act as secondary factors. The demonstrated approach for efficient pseudocapacitive Mg/Li-ion intercalation enhanced by nanointerfaces can be further exploited in the development of other high performance electrodes for advanced Mg–Li hybrid batteries.

Bi2MoO6/TiO2 heterojunction modified with Ag quantum dots: a novel photocatalyst for the efficient degradation of tetracycline hydrochloride

Zhuangzhuang Yin,Shihan Qi,Shangkun Deng,Kang Xu,Zhu Liu,Miao Zhang,Zhaoqi Sun

In this study, a Bi 2 MoO 6 /TiO 2 heterojunction photocatalyst modified with Ag quantum dots was successfully synthesized. The results demonstrated that Ag–Bi 2 MoO 6 /TiO 2 exhibited excellent photoelectrochemical performance and photocatalytic activity for the degradation of tetracycline hydrochloride. The catalyst had the best photocurrent density with a maximum value of 103.0 µA/cm 2 , which was 11.7 times higher than that of unmodified TiO 2 nanorods. Ag–Bi 2 MoO 6 /TiO 2 significantly increased the absorption intensity and red-shifted with a bandgap of 1.88 eV, which is substantially narrower than that of TiO 2 . Furthermore, it exhibited extremely high photocatalytic activity for the degradation of tetracycline hydrochloride with a degradation rate of 90.8% at 120 min. A photocatalytic mechanism was proposed to explain the principle of tetracycline hydrochloride degradation using this catalyst.

Cellulose-based porous polymer film with auto-deposited TiO2 as spectrally selective materials for passive daytime radiative cooling

Xi Chen,Man He,Shuangjiang Feng,Zhengjian Xu,Hao Peng,Shengnan Shi,Chenghuan Liu,Yuming Zhou

Passive daytime radiative cooling materials significantly alleviate the current energy shortage and global warming without consuming any energy. However, conventional inorganic nanoparticles can hardly achieve excellent cooling effect during daytime due to their low reflectivity . Broadband super white nanoparticle-based radiators demonstrate excellent solar reflectivity under direct sunlight and low absorption. Accordingly, we introduced TiO 2 nanoparticles with the advantages of high refractive index , high infrared emissivity and low solar absorption into the porous cellulose-based film via a facile phase separation strategy. The cavities were distributed around 5 μm in size due to the limited evaporation of solvents, while the introduction of TiO 2 nanoparticles effectively enhanced the solar reflectance to 0.97. Moreover, the scattering model demonstrated that the high solar reflectivity was mainly produced by the randomly agglomerate effect of nanoparticles and these nano-clusters also contribute to a high mid-infrared emissivity. As a result, the photonic film presented about 10 °C cooling capacity even under the high-density solar radiation (~897 W/m 2 ) according to the out-door measurement. The random nano-clusters filling strategy avoids the complicate process of specific size particles and has a significant potential for propel the polymer-based cooling technology to satisfy the need of large-scale thermal management.

Insights on interfacial charge transfer across MoS2/TiO2-NTAs nanoheterostructures for enhanced photodegradation and biosensing&gas-sensing performance

Zhufeng Shao,Wenhao Liu,Yufeng Zhang,Xiujuan Yang,Min Zhong

Novel MoS 2 nanobelts (NBs) decorated highly ordered alignment TiO 2 nanotubes arrays (TiO 2 -NTAs) with promoted photoelectrocatalytic (PEC) photodegradation and sensing performance under UV-Visible light irradiation were successfully synthesized via a facile combination of anodization and electrodeposition procedure. Simultaneously, the MoS 2 /TiO 2 -NTAs nanohybrids presented a significantly enhanced for PEC activity tests, which were mainly ascribed to the synergistic effect between MoS 2 NBs and TiO 2 -NTAs for the efficient separation of photogenerated carriers induced by the enlarged staggered band offset associated with sulfur vacancies defects. Furthermore, self-consistent interfacial charge transfer mechanism and convincing quantitative dynamic process (i.e. rate constant of charge transfer) for MoS 2 /TiO 2 -NTAs type-II nanoheterojunctions mediated with the p -type doping effect are proposed, which were evaluated by nanosecond time-resolved transient photoluminescence (NTRT-PL) and time-resolved photoluminescence (TRPL) spectra, respectively. Following this scheme, the photodegradation rate (η) toward degradation of methyl orange for optimum MoS 2 /TiO 2 -NTAs-2 nanocomplex was 96% irradiated by UV-Visible light, which are 1.2 and 1.1 times than that of MoS 2 /TiO 2 -NTAs-1 and MoS 2 /TiO 2 -NTAs-5, respectively. Furthermore, the PEC biosensing analysis of MoS 2 /TiO 2 -NTAs-2 was performed for detecting the glutathione, leading to an excellent detect limit of 1.6 μM and the sensitivity of 930 mA cm -2  M -1 . Additionally, the sensitivity of gas-sensing for MoS 2 /TiO 2 -NTAs-2 is 3.1, which are 1.3 and 1.1 folds than that of MoS 2 /TiO 2 -NTAs with MoS 2 deposited times 1 min and 5 min, respectively. It is distinctly manifested that the gas sensing performance of MoS 2 /TiO 2 -NTAs-2 toward ammonia gas is superior than that of MoS 2 /TiO 2 -NTAs-1 and MoS 2 /TiO 2 -NTAs-5 in terms of higher sensitivity degree and faster response speed.

Fiber-Optic Surface Plasmon Resonance Sensor for Trace Cadmium-Ion Detection Based on Ag-PVA/TiO2 Sensing Membrane

Ting Li,Wenlin Feng

In-situ growth of TiO2 film on carbonized eggshell membrane as 3D electrode for high-performance lithium storage

Xiao Yu,Xinyi Zhang,Yongjian Lai,Donghai Wang,Yong Liu

3D electrodes have shown extraordinary promise for electrochemical energy storage devices in wearable electronics. However, it is still a significant challenge to rationally design 3D electrode that has the characteristics of lightweight, flexibility, low cost, high performance and miniaturization. In this work, we present a novel design of 3D electrode by directly growing the nanocrystalline TiO 2 film on carbonized eggshell membrane. The unique architecture can supply not only a continuous electron transport pathway through an interconnected carbon fibrous network but also an efficient electrolyte flux via an interpenetrating porous network. Besides, nanocrystalline TiO 2 film on carbonized eggshell membrane offers a short ion diffusion path in the solid-phase, leading to a rapid kinetic of electrochemical reaction. When tested as an anode for Li-ion battery, TiO 2 film in 3D electrode demonstrated excellent electrochemical performance with a large reversible capacity, excellent rate capacity and long life cycling property.

Studies on the size effects of nano-TiO2 on Portland cement hydration with different water to solid ratios

Jinfeng Sun,Liang Tian,Zhuqing Yu,Yu Zhang,Chengdong Li,Guihua Hou,Xiaodong Shen

The effects of using different sizes of nano-TiO 2 (NT) on the hydration characteristics of Portland cement with different water to solid ratios (w/s, solid: cement + NT) were investigated in this study. Cement was partially replaced by NT with two sizes, 5 nm and 25 nm, at weight fractions of 0, 0.5%, 1.0%, 1.5% and 2.0%. The compressive strength, hydration products, hydration degree, pore structures and morphologies of the modified cement pastes were systematically evaluated. The experimental results showed that a suitable NT content effectively enhanced the compressive strength of the cement paste, and this enhancement directly depended on the NT particle size. Cement paste mixed with 5-nm NT resulted in a higher compressive strength than 25-nm NT, irrespective of the w/s ratio. The cement paste with a maximum compressive strength at all the curing ages was obtained using a 0.3 w/s ratio and 0.5 wt% of 5-nm NT (which were therefore identified as the optimal NT parameters). The compressive strength of this cement paste increased by 41.4%, 15.9%, 18.7% and 24.35% at 1, 3, 7 and 28 days, respectively, compared to a control sample. For both NT sizes, the w/s ratio and the NT content controlled the compressive strength development of the paste during the early and late ages, respectively. Compared with 25-nm NT, replacing cement by 5-nm NT within the optimum content range was more effective in accelerating cement hydration, increasing the hydration degree, decreasing the crystal size of Ca(OH) 2 , refining the pore structure and densifying the cement paste at the microscale, all of which increased the compressive strength at the macroscale.