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Li, Ziwei; Das, Sonali; Hongmanorom, Plaifa; Dewangan, Nikita; Wai, Ming Hui; Kawi, Sibudjing
2018 Catalysis Science & Technology
doi: 10.1039/c8cy00622a
The increasing environmental concern on global warming has triggered intensive research on sustainable utilization of greenhouse gases. CO2 (dry) reforming of methane (DRM) is one of the most effective means since it can transform two major greenhouse gases, CO2 and CH4, together into the more valuable synthesis gas. Silica-based micro- and mesoporous materials turned out to be one promising class of catalysts due to their wide availability, high thermal stability and high specific surface area. In this article, we have overviewed the background and key problems lying in DRM as well as the strength and weakness of silica-based materials used for DRM. Recent developments on these silica-based micro- and mesoporous catalysts including Ni-based catalysts, bimetallic catalysts, perovskite catalysts, Ni-based catalysts doped with promoters and core–shell catalysts for DRM have then been presented by summarizing the synthesis methods and reasons leading to the high catalytic performance and carbon resistance. Finally, key challenges and possible strategies to improve these silica-based catalysts for DRM have been discussed.
Johnson, Chloe; Albrecht, Martin
2018 Catalysis Science & Technology
doi: 10.1039/c8cy00681d
NHC iron(ii) piano-stool complexes catalyse the selective semi-hydrogenation of alkynes to alkenes using silanes as reducing agents. Aromatic terminal alkynes are converted to styrenes without over-reduction to ethylbenzene derivatives. Furthermore, internal aryl alkynes afford cis-alkenes with excellent Z-selectivity.
Xie, Yinjun; Hu, Peng; Bendikov, Tatyana; Milstein, David
2018 Catalysis Science & Technology
doi: 10.1039/c8cy00112j
We report the heterogeneously catalyzed hydrogenation of amides to form alcohols and amines. This C–N bond cleavage reaction is catalyzed by silver on γ-alumina, proceeds smoothly in high yields and 100% selectivity, and is effective for both benzamides and aliphatic amides. This is in contrast to amide hydrogenation catalyzed by heterogeneous catalysts, which generally proceeds via C–O bond cleavage. Recycling experiments show that the catalyst Ag/γ-Al2O3 can be easily recovered and regenerated without decrease in catalytic activity.
Fu, Shurong; Zhang, Beibei; Hu, Hongyan; Zhang, Yajun; Bi, Yingpu
2018 Catalysis Science & Technology
doi: 10.1039/c8cy00656c
Photoelectrochemical (PEC) water splitting is a promising method for storing solar energy in the form of hydrogen fuel. However, the high recombination ratios of electron–hole pairs and the sluggish kinetics of the oxygen evolution reaction (OER) severely restrict the PEC efficiency. Herein, we demonstrate that vertically-oriented PtO nanowires could be highly selectively grown on ZnO nanowire arrays to construct a novel cross-linked heterostructure by a light-controlled growth method. The key to PtO nanowire growth and interactions is based on the use of a photogenerated electric field from ZnO nanowire arrays. More importantly, these PtO nanowires are utilized, for the first time, as highly efficient OER cocatalysts in PEC water splitting systems to produce hydrogen and exhibit much higher activities than other Pt species decorated samples. Systematic studies reveal that the excellent PEC performance should be attributed to the pure PtO crystalline phase and vertically-oriented nanowire structure, which could effectively facilitate the hole trapping/transport and provide more active sites for water oxidation. These results provide a new insight and strategy to construct special structured OER cocatalysts on PEC photoanodes for enhancing water splitting performance.
Li, Tian-Tian; Gao, Xia-Jun; Qi, Shi-Chao; Huang, Li; Peng, Song-Song; Liu, Wei; Liu, Xiao-Qin; Sun, Lin-Bing
2018 Catalysis Science & Technology
doi: 10.1039/c8cy00100f
With the growing demand for green chemistry, mesoporous solid strong bases have attracted increasing attention in view of their tremendous potential as eco-friendly catalysts in diverse reactions. In the present study, K-incorporated mesoporous carbon is successfully prepared through high-temperature chemical activation combined with the hard-templating method. The combined method is proved to be very effective at promoting the formation of stable K species that strongly interact with the carbon support. The obtained solid bases thus have both high activity and enhanced water-resistant stability, which is reflected in their catalysis of the transesterification of ethylene carbonate with methanol to dimethyl carbonate. A much higher turnover frequency (TOF) value (430.4 h−1) and better reusability are thus observed, compared with a series of typical and popular solid bases, such as MgO (TOF, 1.0 h−1) and CaO/SBA-15 (TOF, 6.4 h−1).
Mazonde, Brighton; Cheng, Shilin; Zhang, Guihua; Javed, Mudassar; Gao, Weizhe; Zhang, Yu; Tao, Meng; Lu, Chengxue; Xing, Chuang
2018 Catalysis Science & Technology
doi: 10.1039/c8cy00243f
As a distinctive supportable route, the solvent-free synthesis of zeolites not only minimizes the problems of conversional hydrothermal synthesis, but also greatly increases the product yields with advantageous characteristics, such as reduced waste production and a hierarchical pore structure. Herein, we demonstrate using in situ crystal Co/SiO2 to form a hierarchical catalyst with Co particles entrapped inside the ZSM-5 body via a solvent-free process. Na-type zeolite catalysts enhanced the production of gasoline-range (C5–C11) products, with Co@NaZSM-5 giving a high selectivity of 68% in the Fischer–Tropsch synthesis. Obviously, all characterizations showed that these solvent-free synthesized samples had high crystallization and a high surface area for mass transfer. This hierarchical zeolite has the potential to be applied to other similar materials owing to its convenient synthesis method, features, and outstanding results.
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