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117 results on '"Gu, Xianmo"'

30. Dual modification of TiNb2O7 with nitrogen dopants and oxygen vacancies for selective aerobic oxidation of benzylamine to imine under green light

Author

Yu, Zhuobin, Waclawik, Eric, Wang, Zhijian, Gu, Xianmo, Yuan, Yong, Zheng, Zhanfeng, Yu, Zhuobin, Waclawik, Eric, Wang, Zhijian, Gu, Xianmo, Yuan, Yong, and Zheng, Zhanfeng

Abstract

TiNb2O7 powder was prepared by a simple hydrothermal method and subsequent heat treatment. Vo–N–TiNb2O7 was generated by NH3 and ethanol dual treatments. The NH3 treatment produced a new N 2p orbital band above the O 2p valence band and oxygen vacancy (Vo) levels were formed by the ethanol treatment. The photocatalytic performance of modified Vo–N–TiNb2O7 towards selective aerobic oxidation reactions under green light (475–600 nm, peaked at 525 nm) was measured. It exhibits a high conversion of benzylamine (above 90%) at 80 °C over 24 h with selectivity for N-benzylidenebenzylamine greater than 95% under green light, which is much better than the unmodified and mono-modified TiNb2O7. It is suggested that the dual modification alter the electronic band structure of TiNb2O7 and result in a narrower band gap which should be responsible for the enhanced photocatalytic activity.

Published
2017

32. Plasmon-enhanced furfural hydrogenation catalyzed by stable carbon-coated copper nanoparticles driven from metal–organic frameworksElectronic supplementary information (ESI) available. See DOI: 10.1039/d0cy01162b

Author

WangThese authors contributed equally to this work., Ruiyi, Liu, Huan, Wang, Xiaoyu, Li, Xincheng, Gu, Xianmo, and Zheng, Zhanfeng

Abstract

The selective hydrogenation of furfural (FAL) to furfuryl alcohol (FOL) under mild conditions using a non-noble metal catalyst is highly desirable in biomass conversion. Commercial FOL production over a Cu-based catalyst suffers from harsh reaction conditions and significant deactivation due to catalyst instability. Herein, we report stable Cu nanoparticles encapsulated in a few layers of carbon prepared by the pyrolysis of the metal–organic framework HKUST-1 in H2/Ar, which exhibited excellent catalytic performance and stability in FAL hydrogenation under visible light irradiation. The Cu nanoparticles could absorb visible light and generate photoexcited electrons due to the localized surface plasmon resonance (LSPR) effect, and these electrons transferred the energy to the molecules absorbed on the Cu NP surface, inducing effective dissociation of H2and hydrogenation of FAL. This study provides guidance for designing stable Cu-based LSPR photocatalysts and a mild route for biomass conversion in compliance with green chemistry.

Published
2020
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33. Efficient photocatalytic oxidative deamination of imine and amine to aldehyde over nitrogen-doped KTi3NbO9under purple lightElectronic supplementary information (ESI) available. See DOI: 10.1039/d0cy01338b

Author

Yu, Zhuobin, Gu, Xianmo, Wang, Ruiyi, Wang, Jie, Zhao, Jian, Pei, LinJuan, and Zheng, Zhanfeng

Abstract

KTi3NbO9nanoparticles were fabricated viaa simple hydrothermal method with a post-calcination treatment. The nitrogen doping (N-KTi3NbO9) leads to a narrow band gap, which in turn facilitates efficiently catalysis of imine deamination under purple light that matches its absorption spectra. Furthermore, N-KTi3NbO9exhibits excellent performance in the tandem reaction of photocatalytic imine formation and deamination from various amines. The conversion of benzylamine was up to 100% with >85% benzaldehyde selectivity.

Published
2020
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34. Probing the mechanism of benzaldehyde reduction to chiral hydrobenzoin on the CNT surface under near-UV light irradiation

Author

Wang, Yunwei, Ren, Pengju, Gu, Xianmo, Wen, Xiaodong, Wang, Yingyong, Guo, Xiang-Yun, Waclawik, Eric, Zhu, Huai Yong, Zheng, Zhanfeng, Wang, Yunwei, Ren, Pengju, Gu, Xianmo, Wen, Xiaodong, Wang, Yingyong, Guo, Xiang-Yun, Waclawik, Eric, Zhu, Huai Yong, and Zheng, Zhanfeng

Abstract

Metal-free CNTs exhibit high activity (conversion rate 99.6%, 6 h) towards the synthesis of chiral hydrobenzoin from benzaldehyde under near-UV light irradiation (320–400 nm). The CNT structure before and after the reaction, the interaction between the molecule and the CNT surface, the intermediate products, the substitution effect and the influence of light on the reaction were examined using various techniques. A photo-excited conduction electron transfer (PECET) mechanism for the photocatalytic reduction using CNTs has been proposed. This finding provides a green photocatalytic route for the production of hydrobenzoin and highlights a potential photocatalytic application of CNTs.

Published
2016

36. ZnNb2O6fibre surface as an efficiently product-selective controller for the near-UV-light-induced nitrobenzene reduction reactionElectronic supplementary information (ESI) available: EDS, TEM/HRTEM images, UV-vis absorption spectrum, valence-band XPS spectra, proposed band structure and catalytic stability of ZnNb2O6, kinetic plots, product distribution over modulation of PHA selectivity, FT-IR absorption spectra of the surface of ZnNb2O6, and the optimized (040) surface of ZnNb2O6. See DOI: 10.1039/c9cy01257e

Author

Wang, Jie, Ge, Zhenyu, Pei, Linjuan, Kong, Peng, Wang, Ruiyi, Zhu, Pengqi, Liu, Meixian, Gu, Xianmo, and Zheng, Zhanfeng

Abstract

A high aniline yield was achieved by the combination of near-UV light as the driving force of nitrobenzene reduction and a ZnNb2O6surface as the product-selective controller. Here, a ZnNb2O6fibre, having a wide band gap and both acidic and basic sites, was exploited by a novel ion-exchange method to study the effect of the surface acidity and basicity of catalysts on the product selectivity under near-UV light irradiation without the interference of photo-generated carriers. ZnNb2O6showed the highest aniline yield compared to Nb2O5and ZnO. The results of experimental and theoretical calculations confirmed that the acidic sites on the surface of ZnNb2O6promoted the breakage of the N–O bond in the intermediate phenylhydroxylamine while the basic sites were attached to the dissociated hydrogen of isopropyl alcohol, resulting in high aniline selectivity.

Published
2019
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38. Dual modification of TiNb2O7 with nitrogen dopants and oxygen vacancies for selective aerobic oxidation of benzylamine to imine under green light.

Author

Wang, Zhijian, Gu, Xianmo, Zheng, Zhanfeng, Yu, Zhuobin, Waclawik, Eric R., and Yuan, Yong

Abstract

TiNb2O7 powder was prepared by a simple hydrothermal method and subsequent heat treatment. Vo–N–TiNb2O7 was generated by NH3 and ethanol dual treatments. The NH3 treatment produced a new N 2p orbital band above the O 2p valence band and oxygen vacancy (Vo) levels were formed by the ethanol treatment. The photocatalytic performance of modified Vo–N–TiNb2O7 towards selective aerobic oxidation reactions under green light (475–600 nm, peaked at 525 nm) was measured. It exhibits a high conversion of benzylamine (above 90%) at 80 °C over 24 h with selectivity for N-benzylidenebenzylamine greater than 95% under green light, which is much better than the unmodified and mono-modified TiNb2O7. It is suggested that the dual modification alter the electronic band structure of TiNb2O7 and result in a narrower band gap which should be responsible for the enhanced photocatalytic activity. [ABSTRACT FROM AUTHOR]

Published
2017
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48. Surfactant-free hydrothermal synthesis of sub-10 nm γ-Fe2O3–polymer porous composites with high catalytic activity for reduction of nitroarenes.

Author

Gu, Xianmo, Sun, Zhenhua, Wu, Shuchang, Qi, Wei, Wang, Haihua, Xu, Xianzhu, and Su, Dangsheng

Subjects
*NITROAROMATIC compounds, *POLYMERS, *CATALYTIC activity, *CATALYSIS, *POROUS materials
Abstract

Porous γ-Fe2O3–polymer composites were synthesized by a novel one-pot surfactant-free hydrothermal approach. The γ-Fe2O3–polymer composites consisting of 3.5 nm γ-Fe2O3 nanoparticles and porous polymers exhibited high catalytic activity and recycling performance in the reduction of nitroarenes. [ABSTRACT FROM AUTHOR]

Published
2013
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49. Construction of nano-TiO2decorated titanosilicate core-shell structure: Highly efficient oxygen activation for the degradation of Rhodamine B under visible light and excellent recycling performance

Author

Pei, Linjuan, Gu, Xianmo, Zhang, Yantao, Wang, Jie, Tan, Hao, Wang, Pengfei, and Zheng, Zhanfeng

Abstract

To improve the photocatalytic performance of TiO2and make it easier to recycle, the titanosilicate@anatase core-shell micro-nanostructure photocatalysts were designed. The titanosilicate@anatase core-shell micro-nanostructure was fabricated by a two-step method: an acid-assisted hydrothermal treatment of the hydrogen-form natisite and a subsequent calcination. In the first step, the dissolution and recrystallization of Ti species led to the formation of TiO2shell over the titanosilicate; in the second step, the calcination not only facilitated the formation of Ti−O−Si bond, but also improved the crystallization of TiO2shell. The rutile TiO2was not detected even at 900 °C, which could be attributed to the strong interaction between TiO2nanocrystals and the titanosilicate core through Ti−O−Si bond at the interface. The formation of Ti−O−Si bond also changed the surface characteristic of the TiO2shell, which facilitated the enrichment of RhB dye molecules around the catalyst and induced the fast production of the O2•−. The collaboration of the core and the shell contributed to the quick degradation of RhB under visible light and the excellent recycling performance. The growth kinetics of the core-shell micro-nanostructure has been studied in detail, which provided a novel and facile synthesis strategy for the fabrication of TiO2micro-nanostructure easy to be recycled.

Published
2021
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50. Multifunctional oxygen vacancies in WO3–x for catalytic alkylation of C–H by alcohols under red-light.

Author

Zhu, Pengqi, Sun, Xichen, Wang, Yunwei, Zhang, Jin, Gu, Xianmo, and Zheng, Zhanfeng

Subjects
*ALKYLATION, *PHOTOCATALYSTS, *CARRIER density, *SURFACE charges, *ALCOHOL, *CHEMICAL energy
Abstract

Plasmonic WO 3– x was firstly applied to photocatalytic alkylation of arenes under 660 nm red light irradiation. Oxygen vacancies in WO 3– x can extend light absorption range and enhance charge separation efficiency and surface oxygen vacancies can promote surface reaction kinetics via promoting chemisorption of alcohols on WO 3– x surface, which ensure the high activity and selectivity of photocatalytic alkylation over WO 3– x. [Display omitted] • WO 3– x shows high photocatalytic activity for alkylation of C–H with alcohols. • Alkylation of C–H is a radical process over WO 3– x under red light irradiation. • Oxygen vacancies promote surface reaction kinetics and light absorption abilities. Surface reaction kinetics and light absorption properties of a photocatalyst are essential demands for efficiently solar to chemical energy converting. In this study, plasmonic WO 3– x was firstly applied to photocatalytic alkylation of arenes under red light irradiation. The oxygen vacancies, both on the surface and in the bulk of WO 3– x , allow abundant free electrons to increase carrier densities and support its LSPR using low energy photons. The surface oxygen vacancies have more functions: they not only release surface tungsten sites which ensure the chemisorption of alcohols due to the coordianation ability but also promote the activation of alcohols via an efficient transport of the holes on the neighbouring O sites to chemisorption alcohol species. In brief, the bulk oxygen vacancies provide abundant charges and the surface vacancies promote the bond adsorption and activation abilities, which ensure the high efficiency of photocatalytic alkylation of C–H. [ABSTRACT FROM AUTHOR]

Published
2021
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