Generations Yi Ma,† Xiuli Wang,† Yushuai Jia,† Xiaobo Chen,‡ Hongxian Han,*,† and Can Li*,† †State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Dalian National Laboratory for Clean Energy, 457 Zhongshan Road, Dalian 116023, China ‡Department of Chemistry, College of Arts and Sciences, University of Missouri-Kansas City, 5100 Rockhill Road, Kansas City, Missouri 64110, United States

Titanium dioxide-based nanomaterials for photocatalytic fuel generations.

Composite Titanium Dioxide Nanomaterials

Zeolites are versatile and fascinating materials which are vital for a wide range of industries, due to their unique structural and chemical properties, which are the basis of applications in gas separation, ion exchange and catalysis. Given their economic impact, there is a powerful incentive for smart design of new materials with enhanced functionalities to obtain the best material for a given application. Over the last decades, theoretical modeling has matured to a level that model guided design has become within reach. Major hurdles have been overcome to reach this point and almost all contemporary methods in computational materials chemistry are actively used in the field of modeling zeolite chemistry and applications. Integration of complementary modeling approaches is necessary to obtain reliable predictions and rationalizations from theory. A close synergy between experimentalists and theoreticians has led to a deep understanding of the complexity of the system at hand, but also allowed the identification of shortcomings in current theoretical approaches. Inspired by the importance of zeolite characterization which can now be performed at the single atom and single molecule level from experiment, computational spectroscopy has grown in importance in the last decade. In this review most of the currently available modeling tools are introduced and illustrated on the most challenging problems in zeolite science. Directions for future model developments will be given.

https://biblio.ugent.be/publication/6977178/file/8575390.pdf

Advances in theory and their application within the field of zeolite chemistry.

Despite the enormous research efforts in recent years regarding lignin depolymerisation and functionalisation, few commercial products are available. This review provides a summary and viewpoint of extensive research in the lignin-to-product valorisation chain, with an emphasis on downstream processing of lignin derived feedstock into end products. It starts with an introduction of available platform chemicals and polymeric derivatives generated from lignin via existing depolymerisation and functionalisation technologies. Following that, detailed analyses of various strategies for the downstream processing of lignin derived platform chemicals and materials into fuels, valued-added chemicals and functional polymers are provided. A concise techno-economic analysis of various downstream processes is conducted based on the market demand of the end product, economic potential and technological readiness, enabling the identification of processes that are potentially both economically competitive and commercially feasible, and shedding light on processes which deserve further technological development. We wish this review will stimulate further advances in the sustainable production of value-added products from lignin to integrate this invaluable “bio-waste” into the chemical/materials supply chain.

Downstream processing of lignin derived feedstock into end products.

A ball-flower like NiO/g-C3N4 heterojunction composite was synthesized via a hydrothermal deposition method combined with subsequent calcination route. The NiO/g-C3N4 heterojunction exhibited a superior performance in CO2 photoreduction. A maximum CO yields of 4.17 μmol/(h g-cat) had been obtained on 40% NiO/g-C3N4 composite, which was 2.5 and 7.6 times as high as the pure g-C3N4 and NiO respectively. The promotion mechanism could be ascribed to the perfect band matching and efficient internal charge transfer within the p-n junction, which results in high-efficiency separation of photogenerated electron-hole pairs, strong visible-light response and high specific surface area.

Ball-flower like NiO/g-C3N4 heterojunction for efficient visible light photocatalytic CO2 reduction

P–N junction mechanism on improved NiO/TiO2 photocatalyst

Catalytic deoxygenation on transition metal carbide catalysts

High aromatics yield (>90%, benzene and toluene) was obtained from vapor phase hydrodeoxygenation (HDO) of phenolic compound mixtures containing m-cresol, anisole, 1,2-dimethoxybenzene, and guaiacol over molybdenum carbide catalysts (Mo2C) under atmospheric pressure at 533–553 K, even with H2 to phenolic compound molar ratios of ∼3,300. Toluene selectivity increased proportionately (4%–66%) to m-cresol content in HDO of phenolic compound mixtures (molar composition: 0%–70%) at quantitative conversion. Phenol selectivity increased with decreasing conversion, implying that the aryl-methoxyl bond in guaiacol is cleaved first, before the aryl-hydroxyl bond. Low selectivity to cyclohexane and methylcyclohexane (

/pdf/mo2c-catalyzed-vapor-phase-hydrodeoxygenation-of-lignin-2obiskydl7.pdf

Mo2C catalyzed vapor phase hydrodeoxygenation of lignin-derived phenolic compound mixtures to aromatics under ambient pressure

Mesoporous metal carbides are of particular interest as catalysts for a variety of reactions because of their high surface areas, porous networks, nanosized walls, and unique electronic structures. Here, two ordered mesoporous metal carbides, Mo2C and W2C, were synthesized using a nanocasting approach coupled with a simultaneous decomposition/carburization process under a continuous methane flow. The as-synthesized mesoporous Mo2C and W2C have three dimensionally ordered porous structures, large surface areas (70–90 m2 g–1), and crystalline walls. In vapor-phase anisole hydrodeoxygenation (HDO) reactions, they exhibited turnover frequencies of approximately 9 and 2 × 10–4 mol molCO–1 s–1, respectively, at relatively low reaction temperatures (423–443 K) and ambient hydrogen pressures. Notably, the ordered mesoporous W2C catalyst showed a greater than 96% benzene selectivity in anisole HDO, the highest benzene selectivity reported to date.

Ordered Mesoporous Metal Carbides with Enhanced Anisole Hydrodeoxygenation Selectivity

C4–C6 olefin β-scission rate constants were inferred from experimental studies at 773–813 K and <15% conversion by considering every C4–C6 olefin isomer and all available β-scission modes: 2° to 2° (C), 1° to 3° and 3° to 1° (E), 1° to 2° and 2° to 1° (D), and 1° to 1° (F). Group contribution methods were implemented to assess adsorption enthalpies and entropies of C4–C6 olefin isomers on H-ZSM-5 via the development of group correction terms for surface alkoxides; a linear dependence of enthalpy (or entropy) of formation difference between a surface alkoxide and a gas-phase alkane on carbon number was considered. Tertiary alkoxides have the smallest adsorption constants among surface adsorbates, and the resulting low coverage of highly substituted alkoxides restricts their contribution to alkene cracking pathways. Intrinsic β-scission rate constants (kE:kC:kD:kF ratio of 1094:21:8:1 at 783 K) and activation energies (EinE < EinC < EinD < EinF) from experimentally observed effluent compositions of C4–C6 ol...

Cha Jung Chen

Papers

P–N junction mechanism on improved NiO/TiO2 photocatalyst

Catalytic deoxygenation on transition metal carbide catalysts

Mo2C catalyzed vapor phase hydrodeoxygenation of lignin-derived phenolic compound mixtures to aromatics under ambient pressure

Ordered Mesoporous Metal Carbides with Enhanced Anisole Hydrodeoxygenation Selectivity

Kinetics and Thermochemistry of C4–C6 Olefin Cracking on H-ZSM-5