Journal of Chemistry
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2019
·
IF 1.727
Shiyun Tang,Jingyu Ran,Junjiang Guo,Anjiang Tang
To obtain high stable and effective TiO2 photocatalyst, nano-N-doped TiO2@SiO2 (TiO2−xNx@SiO2, 0 ≤ x ≤ 2) composite aerogels were synthesized by the sol-gel method combined with supercritical drying and direct oxidation process. The adsorption/photocatalytic degradation efficiency of TiO2−xNx@SiO2 aerogels was evaluated by the degradation of RhB in aqueous solution under visible light irradiation. The physiochemical properties of the aerogels were examined by XRD, FT-IR, TEM, SEM, TG/DTA, and BET methods. It was found that the specific surface areas of all TiO2−xNx@SiO2 samples exceeded 700 m2/g and exhibited a honeycomb porous structure with fine particulate morphology. Photocatalytic activity tests show that the 500-TiO2@SiO2 composite aerogel exhibits the best adsorption/photocatalytic degradation rate for RhB, which obtained about 80% of the degradation rate in 30 min under visible light and over 95% after 120 min. On the one hand, the SiO2 aerogels can significantly inhibit the phase transition of TiO2, and the nano TiO2 can be highly dispersed in the SiO2 aerogels; On the other hand, if the oxidation temperature is selected properly, the N-doped TiO2−xNx@SiO2 aerogel can be obtained by simple TiN@SiO2 aerogel oxidation.
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高影响因子
CELLULOSE
·
2019
·Vol. 27
·期 1
·481-491
·
IF 3.917
Sun Zhuangzhi,Li Zhaoxin,Li Wenzong,Bian Fuguo
Solar steam evaporation is regarded as a green and efficient method to achieve desalination and purification. However, the low-efficiency photothermal conversion of its evaporator is an obstacle to widespread application. Focusing on the interface evaporation method through photothermal conversion, the current bottleneck of the technology is that it is impossible to achieve in-depth interface control of the incident light path to obtain higher water evaporation efficiency. We propose a mesoporous cellulose-based hydrogel for the manufacture of a high-efficiency solar steam evaporator. This type of solar evaporator achieves an enhanced capillary force and optical path extension to increase the photothermal conversion efficiency and evaporation rate. These evaporation performance advantages can all be attributed to the dense mesoporous structure, low thermal conductivity, and high light absorption efficiency. The results showed that under a solar light intensity of 1.5 kW m −2 , the mesoporous structure of the MCNT–TiO 2 –SiO 2 –TiN hydrogel-based evaporator has an excellent evaporation rate (1.853 kg m −2 h −1 ) and high solar energy conversion efficiency (77.39%) due to the low thermal conductivity (0.71997 W m −1 k −1 ), high light absorption efficiency (98.3%, wavelength 190–3000 nm) and good hydrophilic properties (XRD and FT-IR tests). Our results demonstrate a new full-hydrogel solar steam evaporation method by using a simple, easily obtained, reusable, and low-cost solar desalination and purification system based on evaporation can yield fresh water from seawater and sewage. The evaporation technique can be used to produce a simple, easily obtained, reusable, and low-cost solar desalination and purification system for pure freshwater resources from seawater and sewage.
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APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Xue Bai,Jia Jia,Yanyan Du,Xiaoyun Hu,Jianli Li,Enzhou Liu,Jun Fan
This is the first time we report that P-doped anatase titanium oxide (TiO 2 ) nanosheets can be fabricated by red phosphorus (RP) and TiO 2 nanosheets using simply hydrothermal method, accompanying variation in surface species viz. Ti 4+ , O 2− , Ti 3+ , oxygen vacancies ( V o ) and P 5+ . The defect and impurity levels induced by moderate doping could facilitate the formation of charge trap centers or avoid the formation of charge recombination centers, resulting in remarkably enhanced photocatalytic activity . Moreover, the enhanced optical absorbance and transfer performance of photo-generated carriers were studied using UV–Vis spectroscopy, photoelectric spectrometry and TR-PL. Importantly, the formation of Ti-O-P bands may accelerated transmission of electrons, giving rise to the effective separation of photo-generated carriers. To the best of our knowledge, the Cr (VI) reduction and RhB removal rate obtained by this hybrid show comparatively competitive among other reports so far. It is believed that this work provide a promising approach for building a novel pathway for electron transport and more photocatalytic reaction centers on photocatalysts.
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ACS Catalysis
·
2019
·
IF 12.221
Zhongzhe Wei,Zihao Yao,Qiang Zhou,Guilin Zhuang,Xing Zhong,Shengwei Deng,Xiaonian Li,Jianguo Wang
The reaction/diffusion kinetics are fundamentally determined by the electronic properties of supported Pd catalysts and further govern the catalytic activity and selectivity in the partial hydrogenation of alkynes. However, how the electronic metal–support interactions and the tradeoff between reaction and diffusion affect the catalytic performance still remain elusive. Here, the optimized catalyst Pd supported on carbon decorated with oxygen-deficient TiO2(Pd/TiO2-VO@C) features a remarkable enhancement in performance for semihydrogenation of 2-methyl-3-butyn-2-ol with a TOF 31-fold higher than that of Lindlar catalyst. The improved performance of Pd/TiO2-VO@C benefits from the fact that TiO2-VO@C subtly modulates the electronic properties of Pd, and an appropriate amount of TiO2-VO allows a decrease in the reaction barrier and C promotes the diffusion ability of the catalyst, achieving the balance between reaction and diffusion. By using microkinetic modeling, the reactivity difference of various catalysts is quantitatively predicted and the calculated turnover frequency volcano curve is rationalized as a function of reaction barrier and diffusion ability, which agrees well with the experimental results. The quantitative regulation of catalytic performance by tuning the support properties is a general strategy, which provides a basis to design robust catalysts for diverse reactions.
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ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Lunlun Gong,Heng Yin,Chengming Nie,Xuran Sun,Xiuli Wang,Mei Wang
Although hybrid photocathodes built by immobilizing molecular catalysts to the surface of semiconductors through chemical linkages have been reported in recent years, systematic and comparative studies remain scarce about the impact of various anchoring groups on the performance, stability, and charge-transfer kinetics of molecular catalyst-decorated hybrid photocathodes for photoelectrochemical (PEC) H2 production. In this study, the molecular cobaloxime catalysts, CoPy-4-X (Py = pyridine, X = PO3H2, COOH, and CONH(OH)), bearing different anchoring groups were synthesized and covalently immobilized to the surface of the porous TiO2 layer coated on a p-Si plate or a fluorine-doped tin oxide glass. The influence of the anchoring groups on the performance of p-Si/TiO2/CoPy-4-X photocathodes was comparatively studied for PEC H2 evolution. Among the tested hybrid photocathodes, the one with a hydroxamate as an anchoring group displayed higher activity and lower charge-transfer resistance than that observed for the electrode with a carboxylate or a phosphonate as the anchoring group. Notably, the catalytic current of p-Si/TiO2/CoPy-4-CONH(OH) was attenuated only by 2.9% in the controlled potential photoelectrolysis tests in borate buffer solution at pH 9 at 0 V versus a reversible hydrogen electrode over 6 h. Moreover, the influence of anchoring groups on the interfacial electron transfer from the TiO2 layer to the immobilized cobaloxime catalyst and electron–hole recombination was studied by transient absorption spectroscopy. These results revealed that the hydroxamate as an anchoring group is superior to the carboxylate and phosphonate groups for speeding up the interfacial electron transfer and firmly immobilizing the molecular catalysts to the metal oxide semiconductors to build efficient and stable hybrid photoelectrodes.
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PubMed
高影响因子
Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 24
·14613-14619
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IF 10.733
Qian Wang,Huaiyan Ren,Yingqiang Zhao,Xinyuan Xia,Fang Huang,Guanwei Cui,Bohui Dong,Bo Tang
The phase junction of nano-TiO2 plays an important role in enhancing its photocatalytic activity. However, the achievement of the green, mild and controllable synthesis of phase-junction nano-TiO2 still remains a big challenge for the large-scale preparation and application. Deep eutectic solvents (DESs) show many advantages in the green and mild preparation of highly active nanomaterials due to their low cost, high environmental friendliness, easy large-scale preparation, tailored structures and tunable properties. In this study, by sharing two H-bond acceptors with one H-bond donor, we successfully used DES as a solvent, template, inhibitor and crystalline phase control agent simultaneously to controllably synthesize heterophase-junction nano-TiO2 with different phase ratios under green and mild reaction conditions (at 180 °C for 18 h). The H2 production rate of photocatalytic water splitting with this catalyst reached up to 14.51 mmol h−1 g−1, which was 20-fold greater than that of commercial P25 TiO2 and also much higher than those of other TiO2 nanostructures. To the best of our knowledge, this rate is the highest value reported so far for photocatalytic H2 production catalyzed by sole TiO2. This higher activity was mainly attributed to the phase junctions and defects. This study will provide a new way for the green, mild, easily controllable and versatile preparation of phase-junction photocatalysts with high efficiency.
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Catalysts
·
2018
·Vol. 8
·期 8
·326
·
IF 3.465
Peng Sun,Jun Zhang,Wenxiu Liu,Qi Wang,Wenbin Cao
In this paper, the Langmuir-Hinshelwood (L-H) model has been used to investigate the kinetics of photodegradation of gaseous benzene by nitrogen-doped TiO2(N-TiO2) at 25 °C under visible light irradiation. Experimental results show that the photoreaction coefficientkpmincreased from 3.992 × 10−6mol·kg−1·s−1to 11.55 × 10−6mol·kg−1·s−1along with increasing illumination intensity. However, the adsorption equilibrium constantKLdecreased from 1139 to 597 m3·mol−1when the illumination intensity increased from 36.7 × 104lx to 75.1 × 104lx, whereas it was 2761 m3·mol−1in the absence of light. This is contrary to the fact thatKLshould be a constant if the temperature was fixed. This phenomenon can be attributed to the breaking of the adsorption-desorption equilibrium by photocatalytically decomposition. To compensate for the disequilibrium of the adsorption-desorption process, photoreaction coefficientkpmwas introduced to the expression ofKLand the compensation form was denoted asKm.KLis an indicator of the adsorption capacity of TiO2whileKmis only an indicator of the coverage ratio of TiO2surface. The modified L-H model has been experimentally verified so it is expected to be used to predict the kinetics of the photocatalytic degradation of gaseous benzene.Keywords:modified L-H model;N-TiO2;photocatalytic degradation;benzene
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高影响因子
TALANTA
·
2018
·
IF 4.244
Chan Gao,Deshuai Zhen,Ni He,Zhengbin An,Qiulan Zhou,Chenyi Li,Craig A. Grimes,Qingyun Cai
High surface area (136 m 2 g −1 ) nanoporous two-dimensional TiO 2 nanoflakes are applied as an adsorbent and meanwhile a matrix for toxic small molecule analysis using positive-ion surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF MS). The TiO 2 nanoflakes enable one-step enrichment and analysis, greatly simplifying the analysis technique. Due to the high enrichment efficiency and low background noise, small molecule organic contaminants at ppt or even sub-ppt concentrations such as malachite green (10 pg/mL), leucomalachite green (10 pg/mL), cetyltrimethylammonium bromide (0.001 pg/mL), rhodamine B (0.001 pg/mL), and crystal violet (0.1 pg/mL) were detected. In addition, malachite green and its metabolite leucomalachite green at ng/mL concentrations were successfully detected from fish blood and fish extracts, and crystal violet and its homologues at ng/cm 2 concentrations were detected from inks on thermal receipt papers obtained from local supermarket.
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PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2018
·
IF 11.698
Yanan Liu,Chenglin Miao,Pengfei Yang,Yufei He,Junting Feng,Dianqing Li
The ultrathin TiO 2 nanosheets (TiO 2 -U) with abundant defects were successfully fabricated as substrates to support well-dispersed Pt nanoparticles with low metal loading by photochemical route (P), with impregnated Pt/TiO 2 -U, Pt/TiO 2 -bulk and photoreduced Pt/TiO 2 -bulk as control samples, to focus on studying the inductive effect of oxygen vacancy-rich ultrathin TiO 2 on highly dispersed Pt nanoparticles, and their synergetic promotional effect for CO 2 photoreduction. As expected, P-Pt/TiO 2 -U exhibited excellent photocatalytic efficiency for the selective conversion of CO 2 into CH 4 and CO. The ultrathin TiO 2 nanosheets with a large number of low coordinative sites and ultralarge surface area promoted the rate of electron-transfer. The ultrafine Pt nanoparticles induced by photochemical strategy facilitated the efficient separation of electron–hole pairs. Furthermore, the synergy of metal and support improved the adsorption ability of CO 2 . These three factors were considered to drive jointly the enhancement of catalytic performance in this system. This work offers deep insights for the design of highly efficient catalysts with coordinatively unsaturated sites for CO 2 photoconversion in the presence of H 2 O.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 54
·期 4
·2975-2989
·
IF 2.993
Zhang Yuheng,Gong Mindong,Liu Xi,Ji Lijun,Yang Zhenglong,Zhu Xiashi
Titanium oxide (TiO 2 ) has been widely investigated as a photocatalytic material for degradation of organic pollutant in waste water. However, nanosized granular TiO 2 nanoparticles are hard to be recycled and re-utilized in water and many cause secondary pollution of water. Hence, we constructed a foam-like photocatalyst, which was composed of carbonaceous support: activated carbon nanotube foams and Ag-doped TiO 2 nanoparticles through a method of a template synthesis and carbonization strategy. The as-prepared photocatalyst evidenced to be hierarchical macroporous and mesoporous and exhibited remarkable photocatalytic performance toward the degradation of unsymmetrical dimethylhydrazine under UV and visible light. The structure characterization and photocatalytic performance investigation confirmed that the enhanced photoresponse was attributed to the high efficiency of charge separation and the surface plasmon resonance effect of metallic Ag. The adsorption synergetic effect of the hierarchical porous structure also played an important role in photodegradation. The as-prepared photocatalyst showed great potential in the treatment of waste water containing organic pollutant.
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高影响因子
APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Dawei Zhang,Gang Wang,Shudi Zhi,Kaile Xu,Lijing Zhu,Wenwei Li,Zhixiang Zeng,Qunji Xue
To improve the separation efficiency and decrease fouling of the membranes used in oil-in-water emulsions separation, a superhydrophilic and underwater superoleophobic TiO 2 /Al 2 O 3 composite membrane with ultra low oil adhesion was designed. TiO 2 nanorod arrays were prepared on Al 2 O 3 porous ceramic membrane surface by simple magnetron sputtering and hydrothermal oxidation. The microstructure and surface photosensitivity of TiO 2 nanorod array-coated ceramic membrane can effectively increase the efficiency of oil-water separation and reduce the degree of surface fouling. The layer of TiO 2 nanorod arrays not only reduced the pore size of traditional ceramic membrane (enhanced sieving effect of porous structures) but also endowed its superhydrophilicity (enhanced flux) and underwater superoleophobicity (enhanced oil/water selectivity and antifouling). Based on the superhydrophilicity (water contact angle (WCA) of 0°) and underwater superoleophobicity (oil contact angle (OCA) higher than 150°) of ceramic membrane, oil droplets were blocked by the membrane (oil-water separation efficiency 99.1% under gravity) and water will pass (flux is maintained at 41.8 L/(m 2 h) under gravity). It also has excellent anti-fouling ability due to the ultra-low oil adhesion force (0.084 mN) of the TiO 2 nanorod array-coating after UV irradiation. These features, combined with energy-saving, low-cost and easy-to-scale manufacturing schemes will be of great versatility and practicality in environmental rehabilitation and wastewater purification.
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 29
·期 24
·21138-21144
·
IF 2.324
Zhu Wentao,Lv Yanqi,Chen Huanhuan,Yang Jiawei,Zhou Xingfu
TiO 2 nanorod arrays of crystalline Cd, Y-co-doped rutile were synthesized and successfully assembled in perovskite solar cells (PSCs) as the photoanode. In this work, CH 3 NH 3 PbI 3−x Cl x was used as the light absorber and spiro -OMeTAD as hole transport material (HTM). The synthesized TiO 2 nanorod arrays were investigated by field emission-scanning electron microscopy (FE-SEM), X-ray powder diffraction (XRD) and UV–Vis diffused reflectance. FE-SEM images indicate that the co-doped TiO 2 nanorod arrays were slightly sparser and shorter in length than that of un-doped ones. XRD pattern demonstrates that the as-prepared TiO 2 nanorod arrays were rutile phase. The UV–Vis spectrum proves that the co-doped samples possess higher light scattering intensity than the un-doped samples, which may contribute to improve the short current density of PSCs. And the band gap of the TiO 2 nanorod shows a positive shift when doped with cadmium and ytterbium. Furthermore, a negative shift in the flat-band potential (V fb ) was also observed. Finally, the device based on co-doped TiO 2 nanorod arrays has improved open circuit voltage (V oc ) and short circuit current density (J sc ). A higher power conversion efficiency (η) of 9.06% was obtained for the co-doped device while 8.12% for the un-doped TiO 2 nanorod arrays. This paper opens a door to multi-element co-doped 1-D nanostructured materials for the improving the open circuit voltage and short circuit current density of perovskite solar cells.
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