Authors:Bahareh A.T. Mehrabadi; Sonia Eskandari; Umema Khan; Rembert D. White; John R. Regalbuto Pages: 1 - 35 Abstract: Publication date: 2017 Source:Advances in Catalysis, Volume 61 Author(s): Bahareh A.T. Mehrabadi, Sonia Eskandari, Umema Khan, Rembert D. White, John R. Regalbuto To gauge the efficacy of the various methods to synthesize supported metal catalysts, over 1500 literature articles from the past 3 years have been surveyed. Platinum catalysts over silica (SiO2), alumina (Al2O3), titania (TiO2), and carbon (C) supports have been selected as examples. We include our work on the methods of strong electrostatic adsorption (SEA) and a newer version of it, charge-enhanced dry impregnation (CEDI). These methods are compared and contrasted to those most prevalent in the literature. SEA and CEDI yield ultra-small nanoparticles, usually less than 1.5nm average particle size, and are simple and scalable, especially CEDI, which is a simple adaptation of common incipient wetness impregnation. These methods can be extended to the synthesis of supported bimetallic nanoparticles with equally efficacious results.
Authors:Abhijit Shrotri; Hirokazu Kobayashi; Atsushi Fukuoka Pages: 59 - 123 Abstract: Publication date: 2017 Source:Advances in Catalysis, Volume 60 Author(s): Abhijit Shrotri, Hirokazu Kobayashi, Atsushi Fukuoka Lignocellulose and chitin are the two most abundant renewable sources of organic carbon available as alternative for chemical and fuel synthesis. Catalytic conversion of these composite polymers to monomers is a multifaceted challenge. Lignocellulose and chitin are inherently unreactive toward chemical attacks as they serve the function of structural materials in plants and animals. A combination of pretreatment and catalytic reaction is necessary to convert these materials into useful small molecules. These upstream reactions involving depolymerization of polymers are the roadblock for realizing future chemicals production based on biomass. In this chapter, we first discuss the pretreatment technologies currently available for lignocellulose and their relevance for catalytic conversion. Catalytic pathways for depolymerization of cellulose, hemicellulose, and lignin are then discussed, highlighting important reactions and mechanism. An analogy is derived between mechanism of cellulose hydrolysis using enzymes and heterogeneous carbon catalysts containing acidic functional groups. Finally, the use of chitin as a renewable carbon source is discussed. The chemical structure of chitin is described along with its origin from crab shells and availability. Recent advances in conversion of chitin to N-acetylglucosamine and its derivatives are described.
Authors:Kang Cheng; Jincan Kang; David L. King; Vijayanand Subramanian; Cheng Zhou; Qinghong Zhang; Ye Wang Pages: 125 - 208 Abstract: Publication date: 2017 Source:Advances in Catalysis, Volume 60 Author(s): Kang Cheng, Jincan Kang, David L. King, Vijayanand Subramanian, Cheng Zhou, Qinghong Zhang, Ye Wang Syngas, a mixture of CO and H2 (CO/H2), is a key platform for the utilization of nonpetroleum carbon resources such as natural gas or shale gas and coal. Syngas can also be produced from renewable carbon feedstocks such as biomass and even CO2. A variety of products including hydrocarbons and oxygenates, which can be fuels and chemicals, may be produced from syngas. The catalytic transformation of syngas into value-added products is the core of C1 chemistry. This review highlights advances in the past decade in catalytic conversions of syngas into hydrocarbons with an emphasis on selective formations of C5+ hydrocarbons, which are mainly used as liquid fuels, and lower (C2–C4) olefins, key building-block chemicals. Since CO2 is also contained in syngas from some resources, the catalytic hydrogenation of CO2 to hydrocarbons will also be briefly described. Fischer–Tropsch synthesis is a well-established process for syngas to hydrocarbons, but many fundamental aspects remain unclear because of the complexity of the reaction. The products of Fischer–Tropsch synthesis usually follow the Anderson–Schulz–Flory distribution, which is very wide and is nonselective for a target product such as liquid fuels or lower olefins. This article highlights recent advances in understanding the active phase of Fischer–Tropsch catalysts and in designing efficient catalysts using new materials. Furthermore, this article pays particular attention to the breakthrough in the selectivity control, which is the most important challenge for scientific research in syngas chemistry. Besides insights into various factors determining product selectivity as well as activity, we will also discuss emerging methodologies and strategies for the selective conversion of syngas into a specific range of hydrocarbons.
Authors:Shutao Xu; Yuchun Zhi; Jingfeng Han; Wenna Zhang; Xinqiang Wu; Tantan Sun; Yingxu Wei; Zhongmin Liu Abstract: Publication date: Available online 8 November 2017 Source:Advances in Catalysis Author(s): Shutao Xu, Yuchun Zhi, Jingfeng Han, Wenna Zhang, Xinqiang Wu, Tantan Sun, Yingxu Wei, Zhongmin Liu Methanol-to-olefins (MTO) conversion is one of the most important reactions in C1 chemistry, which provides a path for producing basic petrochemicals from nonpetroleum resources such as coal and natural gas. Since the 1970s, the processes of methanol conversion to olefins have been developed, and with the great research efforts in the past 30 years, commercialization of MTO process has been achieved in 2010. Many institutions and companies have made great effort in the research on MTO reaction, and significant progresses have been made with respect to the fundamental principle, catalyst synthesis, and process research and development. The application of shape-selective catalysts, such as ZSM-5 and SAPO-34, realizes the efficient conversion of methanol with high selectivity to light olefins, ethene and propene. This review first gives a brief overview of the MTO catalysts and MTO technology development, including fixed-bed and fluidized-bed technologies. The advances in catalysis for MTO conversion have been summarized, and the proposals of the direct reaction mechanism and the indirect reaction mechanism, the strategy for the control of product selectivity, the complicated reaction network of methanol conversion over zeolite and zeotype catalysts, and deactivation of MTO reaction have been discussed in detail. The reaction mechanism for initial carbon–carbon bond formation in the early stage of MTO reaction, and some new insights into initial methanol conversion are discussed by reviewing the latest literature in this field.
Authors:Rengui Abstract: Publication date: 2017 Source:Advances in Catalysis, Volume 60 Author(s): Rengui Li, Can Li Photocatalytic hydrogen production via solar water splitting is one of the most promising solutions for sustainable energy and environmental remedy issues. In the past few decades, photocatalytic water splitting has attracted increasing attention, and extensive efforts have been made to construct efficient heterogeneous water-splitting systems. In this chapter, we review the fundamental scientific advances in photocatalytic water splitting using semiconductor-based photocatalyst, especially in light-absorbing materials, photogenerated charge separation, dual-cocatalyst, and surface catalytic reactions. The chapter focuses on the advances achieved in particulate photocatalyst systems, Z-scheme photocatalyst systems, and hybrid natural–artificial photosynthesis systems. Additionally, technical and economic evaluation of hydrogen production via solar water splitting for potential applications is also briefly discussed. Finally, we present concluding remarks and future directions of photocatalytic water splitting for solar energy conversion.
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