scispace - formally typeset
Search or ask a question
Author

Xiumin Huang

Bio: Xiumin Huang is an academic researcher from Dalian Institute of Chemical Physics. The author has contributed to research in topics: Catalysis & Dimethyl ether. The author has an hindex of 18, co-authored 28 publications receiving 1646 citations.

Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, the effect of calcination temperature on the structural features and catalytic behavior of the MnO x -CeO 2 mixed oxides prepared by modified coprecipitation was further examined, and the catalyst calcined at 773 K showed 100% formaldehyde conversion at a temperature as low as 373 K.
Abstract: MnO x –CeO 2 mixed oxides prepared by sol–gel method, coprecipitation method and modified coprecipitation method were investigated for the complete oxidation of formaldehyde. Structure analysis by H 2 -TPR and XPS revealed that there were more Mn 4+ species and richer lattice oxygen on the surface of the catalyst prepared by the modified coprecipitation method than those of the catalysts prepared by sol–gel and coprecipitation methods, resulting in much higher catalytic activity toward complete oxidation of formaldehyde. The effect of calcination temperature on the structural features and catalytic behavior of the MnO x –CeO 2 mixed oxides prepared by the modified coprecipitation was further examined, and the catalyst calcined at 773 K showed 100% formaldehyde conversion at a temperature as low as 373 K. For the samples calcined below 773 K, no any diffraction peak corresponding to manganese oxides could be detected by XRD measurement due to the formation of MnO x –CeO 2 solid solution. While the diffraction peaks corresponding to MnO 2 phase in the samples calcined above 773 K were clearly observed, indicating the occurrence of phase segregation between MnO 2 and CeO 2 . Accordingly, it was supposed that the strong interaction between MnO x and CeO 2 , which depends on the preparation route and the calcination temperature, played a crucial role in determining the catalytic activity toward the complete oxidation of formaldehyde.

655 citations

Journal ArticleDOI
TL;DR: In this article, a modified coprecipitation method was used for the complete oxidation of formaldehyde and the MnO x −CeO 2 mixed oxides with a Mn/(Mn+Ce) molar ratio of 0.5 exhibited the highest catalytic activity among the Mn O x -Ce O 2 mixed oxide, while the Pt precursors and reduction temperature greatly affected the catalytic performance.
Abstract: MnO x –CeO 2 mixed oxides with a Mn/(Mn + Ce) molar ratios of 0–1 were prepared by a modified coprecipitation method and investigated for the complete oxidation of formaldehyde. The MnO x –CeO 2 with Mn/(Mn + Ce) molar ratio of 0.5 exhibited the highest catalytic activity among the MnO x –CeO 2 mixed oxides. Structure analysis by X-ray powder diffraction and temperature-programmed reduction of hydrogen revealed that the formation of MnO x –CeO 2 solid solution greatly improved the low-temperature reducibility, resulting in a higher catalytic activity for the oxidation of formaldehyde. Promoting effect of Pt on the MnO x –CeO 2 mixed oxide indicated that both the Pt precursors and the reduction temperature greatly affected the catalytic performance. Pt/MnO x –CeO 2 catalyst prepared from chlorine-free precursor showed extremely high activity and stability after pretreatment with hydrogen at 473 K. 100% conversion of formaldehyde was achieved at ambient temperature and no deactivation was observed for 120 h time-on-stream. The promoting effect of Pt was ascribed to enhance the effective activation of oxygen molecule on the MnO x –CeO 2 support.

300 citations

Journal ArticleDOI
TL;DR: In this article, the authors compared the catalytic stability of dimethyl ether to methyl acetate over H-mordenite (HMOR) and pyridine-modified HMOR.

122 citations

Journal ArticleDOI
TL;DR: In this article, a simple hydrothermal process by oxidizing Mn(NO3)2 with AgMnO4 in aqueous solution was used to synthesize Ag−hollandite nanofibers with diameters of 20−40 nm and lengths of 0.5−4 μm.
Abstract: Ag−hollandite nanofibers were synthesized through a simple hydrothermal process by oxidizing Mn(NO3)2 with AgMnO4 in aqueous solution. The temperature was found to play an essential role in determining both the crystalline structure and the morphology of the Ag−hollandite materials, whereas the AgMnO4/Mn(NO3)2 molar ratio affected only the morphology of the product. Ag−hollandite nanofibers with diameters of 20−40 nm and lengths of 0.5−4 μm were prepared at 160 °C and a 2/3 AgMnO4/Mn(NO3)2 molar ratio. X-ray photoelectron spectroscopy surface analysis revealed that the silver species presented as Ag+ and the average oxidation state of manganese was 3.9. More promisingly, the Ag−hollandite nanofibers showed quite high catalytic performance for ethanol oxidation, with ethanol conversion of 75% and acetaldehyde selectivity of 95% at 230 °C for 200 h time-on-stream. The high activity, selectivity, and stability were attributed to the stable presence of Ag+ species and the unique morphology of the Ag−hollandit...

95 citations

Journal ArticleDOI
TL;DR: In this article, the 12-membered ring channels of mordenite were removed while those in the 8-memered ring channels were retained to improve its stability in dimethyl ether carbonylation.

87 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: A critical appraisal of different synthetic approaches to Cu and Cu-based nanoparticles and copper nanoparticles immobilized into or supported on various support materials (SiO2, magnetic support materials, etc.), along with their applications in catalysis.
Abstract: The applications of copper (Cu) and Cu-based nanoparticles, which are based on the earth-abundant and inexpensive copper metal, have generated a great deal of interest in recent years, especially in the field of catalysis. The possible modification of the chemical and physical properties of these nanoparticles using different synthetic strategies and conditions and/or via postsynthetic chemical treatments has been largely responsible for the rapid growth of interest in these nanomaterials and their applications in catalysis. In addition, the design and development of novel support and/or multimetallic systems (e.g., alloys, etc.) has also made significant contributions to the field. In this comprehensive review, we report different synthetic approaches to Cu and Cu-based nanoparticles (metallic copper, copper oxides, and hybrid copper nanostructures) and copper nanoparticles immobilized into or supported on various support materials (SiO2, magnetic support materials, etc.), along with their applications i...

1,823 citations

Journal ArticleDOI
TL;DR: This review has a wide view on all those aspects related to ceria which promise to produce an important impact on the authors' life, encompassing fundamental knowledge of CeO2 and its properties, characterization toolbox, emerging features, theoretical studies, and all the catalytic applications, organized by their degree of establishment on the market.
Abstract: Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40th anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three-way catalysts (TWCs). Apart from this well-established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2-based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water-gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2-based materials has already been acquired, new characterization techniques and powerful theoretical methods are dee...

1,710 citations

Journal ArticleDOI
TL;DR: This Review systematically documents the progresses and developments made in the understanding and design of heterogeneous catalysts for VOC oxidation over the past two decades and addresses in detail how catalytic performance is often drastically affected by the pollutant sources and reaction conditions.
Abstract: It is well known that urbanization and industrialization have resulted in the rapidly increasing emissions of volatile organic compounds (VOCs), which are a major contributor to the formation of secondary pollutants (e.g., tropospheric ozone, PAN (peroxyacetyl nitrate), and secondary organic aerosols) and photochemical smog. The emission of these pollutants has led to a large decline in air quality in numerous regions around the world, which has ultimately led to concerns regarding their impact on human health and general well-being. Catalytic oxidation is regarded as one of the most promising strategies for VOC removal from industrial waste streams. This Review systematically documents the progresses and developments made in the understanding and design of heterogeneous catalysts for VOC oxidation over the past two decades. It addresses in detail how catalytic performance is often drastically affected by the pollutant sources and reaction conditions. It also highlights the primary routes for catalyst deactivation and discusses protocols for their subsequent reactivation. Kinetic models and proposed oxidation mechanisms for representative VOCs are also provided. Typical catalytic reactors and oxidizers for industrial VOC destruction are further discussed. We believe that this Review will provide a great foundation and reference point for future design and development in this field.

1,074 citations

Journal ArticleDOI
TL;DR: In this article, a review discusses recent developments in catalytic systems for the destruction of volatile organic compounds (VOCs) and their sources of emission, mechanisms of catalytic destruction, the causes of catalyst deactivation, and catalyst regeneration methods.

1,014 citations

Journal ArticleDOI
TL;DR: Unscreened surface charge of LSPC-synthesized colloids is the key to achieving colloidal stability and high affinity to biomolecules as well as support materials, thereby enabling the fabrication of bioconjugates and heterogeneous catalysts.
Abstract: Driven by functionality and purity demand for applications of inorganic nanoparticle colloids in optics, biology, and energy, their surface chemistry has become a topic of intensive research interest. Consequently, ligand-free colloids are ideal reference materials for evaluating the effects of surface adsorbates from the initial state for application-oriented nanointegration purposes. After two decades of development, laser synthesis and processing of colloids (LSPC) has emerged as a convenient and scalable technique for the synthesis of ligand-free nanomaterials in sealed environments. In addition to the high-purity surface of LSPC-generated nanoparticles, other strengths of LSPC include its high throughput, convenience for preparing alloys or series of doped nanomaterials, and its continuous operation mode, suitable for downstream processing. Unscreened surface charge of LSPC-synthesized colloids is the key to achieving colloidal stability and high affinity to biomolecules as well as support materials,...

892 citations