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Dive into the research topics where Hongfan Guo is active.

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Featured researches published by Hongfan Guo.


CrystEngComm | 2014

Facile synthesis of TiO2 hollow spheres composed of high percentage of reactive facets for enhanced photocatalytic activity

Bin Wang; Xiao-Ying Lu; Lawrence K. Yu; Jin Xuan; Michael K.H. Leung; Hongfan Guo

In this study, facile synthesis of hollow TiO2 spheres composed of a high percentage of reactive facets (~85%) is successfully prepared with TiOSO4 and HBF4 by the hydrothermal method. Results reveal that hollow TiO2 spheres of 605 nm to 1.21 μm in size are in the anatase phase with sulfur doping. The variation in shell morphologies (e.g. polyhedron and nanosheet) can be realized by adjusting the reactant concentrations, while the molar ratio of TiOSO4 to HBF4 is maintained at 5 : 3. Based on the time-dependent morphology evolution study, the growth mechanism of hollow structure formation via self-templating and dissolution–recrystallization processes is discussed. The effects of reactant concentrations on TiO2 morphology are investigated to understand the dual roles of HBF4. Results also indicate that hollow TiO2 spheres with nanosheet morphology having 85% (001) facets exhibit 1.4–5 times higher performance than their counterparts in photocatalytic hydrogen production. The enhanced photocatalytic activity is ascribed to the combined effects of their unique hollow structure, high BET specific surface area (139.1 m2 g−1) and high percentage of exposed reactive facets (85%). This study demonstrates a promising strategy for large-scale production of hollow TiO2 spheres using a template- and surfactant-free process for photocatalysis applications.


RSC Advances | 2014

Synthesis and characterization of hierarchical TiO2 microspheres composed of nanorods: effect of reaction conditions on nanorod density

Hongfan Guo; Xiao-Ying Lu; Yansong Pei; Hong Chua; Bin Wang; Kuikui Wang; Yindong Yang; Yunyi Liu

Urchin-like hierarchical TiO2 microspheres consisting of numerous nanorods were successfully synthesized by a facile hydrothermal process. The effects of reaction conditions (such as additives and reactant concentrations) on TiO2 morphology, particularly on rod density, were systematically investigated. The relationship between rod density and rod diameter was discussed. Based on the above results including a morphological evolution study, a possible mechanism was also proposed to elucidate the growth process of hierarchical TiO2 microspheres using nanorods as building units.


RSC Advances | 2016

Thermochemical processing of fuels involving the use of molecular oxygen

Hongfan Guo; Qiuxiang Cheng; Ze Jin; Dan Wang; Guangwen Xu; Yunyi Liu

In a high-temperature (e.g., 1000 °C) atmosphere containing combustibles, it is naturally thought that air/O2 should be kept away for fear of combustion and explosion. However, during thermochemical processing (TCP) of carbonaceous fuels (CFs) its actually not that simple. TCP, the process for recovering CFs or converting problematic CFs into preferred ones, is a key technology for efficiently and relatively cleanly utilizing various CFs that supply the majority of the worldwide energy demand. However, TCP is often subject to some obstacles (e.g., high energy input and thermodynamic constraint). This review on extensive literature demonstrates that not only does introducing a controlled amount of O2 (i.e., molecular oxygen) into TCP overcome its many obstacles, but also this O2-assisted strategy is applicable to all of the main CFs currently known. Despite such a wide applicability to CFs, there lacks a comprehensive consideration of various aerobic TCP processes for understanding the O2-assisted strategy as a kind of universal TCP technology for CFs. In this review, we for the first time summarize and discuss the use of O2 in various TCP processes for all of the main CFs. We hope that this review can inspire more consideration of the various aerobic TCP processes so that these extremely complex processes can be communicated or consulted from each others experience/research findings in order to enlighten, guide or promote their respective development.


RSC Advances | 2015

Morphology and structure of nano MgO prepared by a novel nitrogen-protective pressurization method

Lifeng Chen; Peng Bai; Hongtao Fan; Wei Yu; Hongfan Guo; Wenxiu Li

A new micro stereoscopic structure of nano MgO was prepared by a novel nitrogen-protective pressurization method and characterized by SEM, EDS, and XRD. The nano MgO was formed by spherical units, and under the action of adsorption, the spherical units formed nanosheets by connecting to one another. Moreover, the units and sheets further gathered into laminations of nano MgO. The grain sizes of the nanosheet and laminate nano MgO were 11.8 nm and 367.6 nm, respectively, which were prepared by a novel method. The influence of nano MgO on morphology and structure were revealed by changing the amount of PVA, calcination time, and pressure.


Catalysis Science & Technology | 2018

Greatly changed performance of a metal Pd catalyst by a rather easily formed and removed species–PdHx

Hongxu Yan; Yunyi Liu; Tao Zhang; Ze Jin; Ming Wang; Ying Peng Xie; Hongfan Guo

Pd catalysts, which are often prepared by reducing Pd salts with NaBH4, have been intensely studied in HCOOH dehydrogenation (FAD) for H2 production. FAD can also be used to hydrogenate or reduce various chemicals by using its in situ generated hydrogen, which exhibits superiority over the direct use of H2 gas. Herein, by using FAD to reduce Cr(VI) as a room-temperature probe reaction, we show that some Pd atoms in the catalyst form PdHx under normal conditions during both catalyst preparation and catalytic reaction (NaBH4 or HCOOH as a hydrogen donor). PdHx greatly hinders Cr(VI) reduction and, interestingly, boosts H2 generation. That is to say, PdHx can be negative or positive species, depending on the focused product. The reason for this phenomenon was also analyzed. Heat treatment for only 10 min can destroy PdHx species and thus, improve the activity for Cr(VI) reduction by up to ∼3 times, which is effective in each catalyst reuse. These findings are critical for controlling the design and functioning of Pd catalyst.


Energy Sources Part A-recovery Utilization and Environmental Effects | 2016

The effect of minerals on the pyrolysis and the combustion of oil shale

Hongfan Guo; Qiuxiang Cheng; Ze Jin; Dan Wang; Kuikui Wang; Yang Ding; Hong Zhu; Yunyi Liu

ABSTRACT Oil shale (OS) is a particularly promising alternative fossil fuel source. However, very different from coal, its inorganic mineral content is very high. The organic matters (mainly kerogen) are finely distributed in the inorganic minerals. Therefore, the minerals may affect the processing of OS, whose elucidation is critical to the choice of processing conditions. In this work, different minerals (SiO2, CaCO3, and Al2O3) were added to OS with different mass ratios of OS to mineral, respectively. Then, the thermogravimetric (TG) technique was employed to analyze the reaction behavior of these different OS/mineral mixtures in N2 and in air for studying the influence of minerals on the OS pyrolysis in N2 (i.e., retorting) and on the OS combustion in air. The results show that CaCO3 and Al2O3 have a promoting effect on both pyrolysis and combustion of OS, and they can decrease the reaction activation energy of both kinds of processes. However, SiO2 has an inhibitive effect and can increase the reaction activation energy for both kinds of processes. It is hoped that the present study can further increase the understanding toward the effect of different minerals on the OS reactions.


Catalysis Communications | 2017

Gold nanoparticles on cyanuric acid-based support: A highly active catalyst for the reduction of 4-nitrophenol in water

Hongfan Guo; Yangyang Ren; Qiuxiang Cheng; Dan Wang; Yunyi Liu


Fuel | 2015

Strengthening the applicability of self-heating retorting process to oil shale via co-retorting

Hongfan Guo; Yindong Yang; Kuikui Wang; Yansong Pei; Qicheng Wu; Yunyi Liu


Fuel | 2015

Identifying the reaction mechanism of oil-shale self-heating retorting by thermal analysis techniques

Hongfan Guo; Yansong Pei; Kuikui Wang; Qiuxiang Cheng; Yang Ding; Ze Jin; Yindong Yang; Qicheng Wu; Yunyi Liu


Hydrometallurgy | 2015

Preparation of Mg(OH)2 with caustic calcined magnesia through ammonium acetate circulation

Hongfan Guo; Yansong Pei; Zhuo Wang; Yindong Yang; Kuikui Wang; Jiayang Xie; Yunyi Liu

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Yunyi Liu

Shenyang University of Chemical Technology

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Dan Wang

Shenyang University of Chemical Technology

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Kuikui Wang

Shenyang University of Chemical Technology

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Qiuxiang Cheng

Shenyang University of Chemical Technology

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Yansong Pei

Shenyang University of Chemical Technology

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Ze Jin

Shenyang University of Chemical Technology

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Yang Ding

Shenyang University of Chemical Technology

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Yindong Yang

Shenyang University of Chemical Technology

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Bin Wang

Hong Kong Applied Science and Technology Research Institute

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Hong Zhu

Beijing University of Chemical Technology

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