Molecular Catalysis
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2022
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IF 5.089
Xiaoda Niu,Shuang Liu,Yong Men,Lin Li,Liangmin Xiong,Kailiang Guo,Junzhe Xu,Kunfeng Zhao,Ya Li,Wei An,Jinguo Wang
Hydrogenation of quinones is an efficient way to produce hydroquinone compounds. Typically, 2,3,5-trimethylhydroquinone (TMHQ), the key intermediate of vitamin E, can be produced via hydrogenation of 2,3,5-trimethylbenzoquinone (TMBQ). In order to effectively obtain the target products, the exploration of efficient heterogeneous catalysts is highly desired. In this study, supported Pd nanocluster catalysts (PdN/TiVo) were designed through a deposition-precipitation method over TiO 2 support with surface defects (TiVo) to achieve high atomic utilization efficiency of the noble metal Pd under mild reaction conditions. The characterization showed that oxygen vacancies generated by H 2 reduction on the support TiO 2 acted as specific sites to promote the formation of the coupled eutectic growth structure composed of the active metal Pd and TiVo. The active metal Pd which not only exhibited high dispersion but also formed electron-rich active sites can activate H 2 while the Ti 3+ atoms at oxygen vacancy sites can adsorb the oxygen species from TMBQ, thereby a synergistic catalytic effect can be shown to enhance the adsorption and hydrogenation of C=O bonds. Thus PdN/TiVo revealed a high yield of TMHQ of 96% and TOF of 276 min −1 under a considerably wild condition (45°C, 0.2 MPa, 60 min). By comparison, state-of-the-art carbon based Pd catalysts (PdN/C) acquired only 29% yield and 41 min −1 TOF in the same way. The simultaneous engineering of Pd catalyst and oxygen vacancies on TiO 2 offers a new strategy to develop efficient heterogeneous catalysts for hydrogenation of quinones.
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SENSORS AND ACTUATORS B-CHEMICAL
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2022
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IF 9.221
Dan Zhao,Xianfa Zhang,Wenjing Wang,Lili Sui,Chuanyu Guo,Yingming Xu,Xin Zhou,Xiaoli Cheng,Shan Gao,Lihua Huo
Real-time detection of herbicides has been a challenge for the application of metal oxide gas sensors. In this paper, we report the application of TiO 2 sensors with oxygen vacancies for the detection of isopropylamine . Spherical structure with oxygen vacancies was successfully prepared by a simple one-step hydrothermal method combined with ionic liquid as morphology regulator. The morphology and structure of the materials were analyzed using XRD, SEM and TEM. Further studies reveal that the oxygen vacancies in this material play an important role in the detection of isopropylamine. The sensor exhibits excellent selectivity, moisture resistance and long-term stability. The response is 61.7–100 ppm isopropylamine, along with fast response time of 22 s. It is noteworthy that the lower limit of detection for isopropylamine can reach 0.2 ppm, which is very meaningful to practical application of detecting gas residues. The excellent performance can primarily be attributed to the formation of abundant oxygen vacancies into the material, which increases the adsorption capacity of gas molecules. This new sensing design strategy offers a vital reference to extend the application of non-metallic elements doped metal oxide semiconductors .
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ACS Applied Energy Materials
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2022
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IF 6.959
Yi Jiang,Yile Dai,Qing Wang,Jianfeng Dai
While transparent photoanodes are highly desired for smart energy devices, their performance is still far from expectation. In the present work, a transparent TiO2 film was prepared using a two-step spin-coating method, which served as photoanodes of quantum dot-sensitized solar cells (QDSSCs). A porous TiO2 photoanode prepared by P25 was also fabricated for comparison. Compared with the porous TiO2 photoanode, QDSSCs based on the transparent TiO2 film showed an obviously declined short-circuit current density (Jsc) but greatly improved fill factor (54.3%), resulting in a larger power conversion efficiency (4.32%). The reason is due to the decreased series resistance and increased shunt resistance of solar cells based on the transparent TiO2 photoanode, which is consistent with the requirement of solar cells to load resistance. The present work proves that the transparent TiO2 film has great potential in the field of transparent solar cells.
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JOURNAL OF HAZARDOUS MATERIALS
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2022
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IF 14.224
Zhendong Yu,Suhang Xun,Meizan Jing,Haofeng Chen,Weiyu Song,Yanhong Chao,Mohammad Rahmani,Yuxiao Ding,Mingqing Hua,Jian Liu,Wenshuai Zhu
To prevent SO x emission and produce low-sulfur diesel oil, we develop a 3D assembly TiO 2 nanoflower catalyst with controllable oxygen vacancies for oxidative desulfurization (ODS) in diesel oil. The roles of oxygen vacancy (OV) and associated Ti 3+ in TiO 2 are fully discussed: the increased OV and Ti 3+ are beneficial for the promoted chemical adsorption of peroxy groups, from − 0.5 eV to − 1.26 eV; also facile to the reduction of the energy barriers of O-O and O-H bonds cleavage, respectively by 1.38 eV and 1.24 eV, thus greatly boosting the generation of hydroxyl radicals·OH and superoxide radicals·O 2 - . Besides, the ODS reaction undergoes two possible pathways, the mechanism and the kinetics are investigated. Above all, the 100% ODS rate can be obtained in only 30 min under optimal conditions, showing a promising perspective of oxygen vacancy engineering for converting hazardous sulfides into high-value chemicals.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2021
·Vol. 32
·期 20
·24845-24855
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IF 2.478
Chen Peiran
Herein, the mechanically exfoliated ultrathin g-C 3 N 4 nanosheets (NSs) are used to decorate TiO 2 hollow microspheres to obtain composite core–shell photocatalysts. The composite hollow microspheres are analyzed through PXRD, Raman spectroscopy, N 2 adsorption–desorption measurements, SEM, TEM, HRTEM, XPS, UV–Vis diffuse reflectance spectra, UPS measurements, PL spectra, photocurrent curves, and EIS spectra. The obtained results show that the composite microspheres have improved visible-light response and boosted carrier separation. Furthermore, the synthesized samples have excellent photodegradation performance for the antibiotic tetracycline and rhodamine B (RhB) under visible light, and the corresponding photodegradation rates are 94.5 and 96.5% at 60 min. In addition, the synthesized catalysts also maintain excellent stability in multiple cycles of experiments. Based on the experimental results, a possible photodegradation pathway on composite microspheres has also been proposed.
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Catalysts
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2021
·Vol. 11
·期 10
·1186
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IF 4.146
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
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Journal of Environmental Chemical Engineering
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2021
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IF 5.909
Shasha Tang,Jie Yao,Hongyuan Liu,Yan Zhang
Although considered as a promising candidate for photocatalytic bromate reduction, TiO 2 is restricted by its fast recombination of photo-induced charge carriers. In this paper, a series of efficient photocatalysts (TiO 2 /TC) were prepared by coupling commercial titania (P25) with titanium carbide MXene (Ti 3 C 2 ) via a simple hydrothermal method, where Ti 3 C 2 was utilized as a noble-metal-free cocatalyst. Batch experiments of photocatalytic bromate removal by TiO 2 /TC composites were conducted under UV irradiation. Its performance and mechanism were also investigated. The results showed that more than 95% of bromate could be removed by TiO 2 /TC-1 composite (Ti 3 C 2 and P25 in a mass ratio of 1%) in 15 min, and its removal rate was 4.87 times higher than that of pure P25. The photocatalytic reduction of bromate by TiO 2 /TC was an interfacial reaction, and bromide was the main product. The greatly improved activity of TiO 2 /TC composites was attributed to the improved separation efficiency of photogenerated charge carriers and narrower band gap. TiO 2 /TC-1 composite exhibited a longer lifetime (6.05 ns) of electron-hole pairs than pristine P25 (4.31 ns). Moreover, due to its excellent electrical conductivity, Ti 3 C 2 functioned as “an electron sink” to accumulate photoinduced electrons from the excited P25. And the Schottky barrier formed in the tight Ti 3 C 2 -P25 interface provided a unidirectional channel for electron transfer , facilitating the separation of electron-hole pairs. In addition, TiO 2 /TC-1 composite had a good stability in bromate removal. This work highlights the potential of Ti 3 C 2 as a noble-metal-free photocatalytic cocatalyst and explores the possible expansion of the application of MXene.
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Environmental Technology & Innovation
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2021
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IF 5.263
Xuecheng Ping,Yan Zhang,Qian Zhao,Yun Lu,Liang Hao
Flexible TiO 2 nanograss array film was prepared by simple chemical oxidation of Ti wire mesh at a low temperature of 353 K. To improve its visible-light-driven photocatalytic activity, we further carried out a low-temperature chemical reduction to introduce oxygen vacancies in the solution of ethylene glycol (EG) and ammonium fluoride (NH 4 F). The results of XPS and EPR confirmed the formation of surface and bulk oxygen vacancies was confirmed, and their concentrations increased as the reduction time increased. Compared with the as-annealed TiO 2 film, the as-reduced specimens exhibited higher visible-light-driven photocatalytic activity. When reduction time was 48h, the photocatalytic activity was increased by 15.8 times compared to the as-annealed sample. The remarkable improvement in photocatalytic activity should be ascribed to the oxygen vacancies’ introduction. The most excellent photocatalytic performance was obtained when a suitable concentration ratio of surface oxygen vacancies to bulk oxygen vacancies was reached. Low-temperature chemical reduction in the solution of EG + NH 4 F is very efficient and convenient for introducing defects such as oxygen vacancies and Ti 3 + .
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APPLIED CLAY SCIENCE
·
2021
·
IF 5.467
Qiuxiang Wang,Zongxue Yu,Yuchuan Liu,Ximei Zhu,Runxuan Long,Xuyang Li
In this project, the Titanium dioxide nanowire (TiO 2 Nw) and layered double hydroxide (LDH) were introduced into the reduced graphene oxide (RGO) to make a composite material and then were assembled on the cellulose acetate (CA) membrane into photocatalytic composite membrane (RLT) through vacuum filtration with photocatalytic effect. The photocatalytic composite membrane (RLT) with high permeability and high rejection was constructed. Compared with other ratios of RLT membranes, RLT-0.5 composite membrane had a higher water flux of 432.38 L·m −2 h −1 bar −1 , and the rejection rate of dye were above 99%. In the rejection process of 10 cycles, that the rejection rate and flux of RLT-0.5 composite membrane to methylene blue (MB), malachite green (Mg) and Congo red (CR) were more stable regardless of whether there was light or no light. Of course, the rejection effect was better under light conditions, showing its excellent photocatalytic performance. In conclusion, RLT-0.5 composite membrane had excellent water purification ability and photocatalytic efficiency, which made it have a wide application in water treatment.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2021
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IF 5.316
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.
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International Journal of Refrigeration
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2021
·
IF 3.629
Zhenghao Jin,Shuhong Li,Runfa Zhou,Mengkai Xu,Weixue Jiang,Kai Du
The newly NH 3 – H 2 O – LiBr working fluid can decrease the power wasted in the generator, thus improves the COP of the ammonia absorption refrigeration system. But the applying of NH 3 – H 2 O – LiBr working fluid decreases the ammonia absorption efficiency, so the COP of the system is still unsatisfactory. To further enhance the COP of the NH 3 – H 2 O - LiBr absorption refrigeration system, TiO 2 nanoparticles are added to the NH 3 – H 2 O - LiBr working fluid in this study. And the effects of TiO 2 nanoparticles concentration on the performances of the generator, absorber, evaporator, condenser, and solution heat exchanger are tested in an ARS experimental system. The experimental results indicate that the addition of TiO 2 nanoparticles increases the P g , P e , P a , and P c , meaning that the value of ammonia produced in the generator increases. Therefore, the COP and iCOP of the system are improved by adding TiO 2 nanoparticles, and the COP is maximum improved by 18.96% compared with the ammonia-water absorption refrigeration system. When the x TiO2 is increased from 0.3% to 0.5%, the increase rate of the COP decreases because the newly added nanoparticles do not disperse well. So 0.3% is a better choice for the TiO 2 nanoparticles concentration when comprehensively considering the dispersion stability of nanoparticles and the COP.
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CHEMICAL ENGINEERING JOURNAL
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2021
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IF 13.273
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.
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