Hydrodeoxygenation of lignin-derived phenolics – a review on the active sites of supported metal catalysts

2020 ◽  
Vol 22 (23) ◽  
pp. 8140-8168
Author(s):  
Xinchao Wang ◽  
Masahiko Arai ◽  
Qifan Wu ◽  
Chao Zhang ◽  
Fengyu Zhao
Keyword(s):  
Phenolic Compounds ◽  
Active Sites ◽  
State Of The Art ◽  
Metal Catalysts ◽  
The State ◽  
Supported Metal Catalysts ◽  
Supported Metal

This article mainly reviews the state-of-the-art achievements of supported metal catalysts and the characteristics and actions of their active sites, working in the reactions involved in HDO of lignin-derived phenolic compounds.

scholarly journals Boosting selective hydrogenation through hydrogen spillover on supported-metal catalysts at room temperature

2021 ◽  
Author(s):  
Sai Zhang ◽  
Zhaoming Xia ◽  
Mingkai Zhang ◽  
Yong Zou ◽  
Xiao Chen ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Active Sites ◽  
Room Temperature ◽  
Metal Catalysts ◽  
Hydrogen Spillover ◽  
Binding Energies ◽  
Supported Metal Catalysts ◽  
High Turnover ◽  
Scaling Relationship ◽  
Supported Metal

Highly efficient hydrogenation of unsaturated substrates with strong absorption on metals at low temperatures is a long-term pursuit. However, due to the scaling relationship of high binding energies on metals, the poor activity and/or selectivity are frequently observed. Herein, we described a strategy of hydrogen spillover to break this scaling relationship to enable highly performed hydrogenation at low temperatures by constructing the dual-active site in supported-metal catalysts. Hydrogen and reactants are selectively activated on metal and the second active sites on support, respectively. Hydrogenation sequentially occurs on the second active sites via hydrogen spillover from metal to support. Easy desorption of surface-bounded products substantially re-generates the active sites. Guided by this design, for cinnamaldehyde hydrogenation, PtCo alloys (for H2 dissociation) supported on hydroxyl-abundant CoBOx (for aldehyde activation) delivered a high turnover frequency of 2479 h-1 (two orders of magnitude over PtCo/C) and 94.5% selectivity of cinnamyl alcohol at room temperature.

scholarly journals Identification of active sites on supported metal catalysts with carbon nanotube hydrogen highways

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Nicholas M. Briggs ◽  
Lawrence Barrett ◽  
Evan C. Wegener ◽  
Leidy V. Herrera ◽  
Laura A. Gomez ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Active Sites ◽  
Metal Catalysts ◽  
Supported Metal Catalysts ◽  
Supported Metal

High-Resolution Scanning Electron Microscopy and Microanalysis of Supported Metal Catalysts

1999 ◽  
Vol 589 ◽  
Author(s):  
Jingyue Liu
Keyword(s):  
High Resolution ◽  
Low Voltage ◽  
Supported Catalysts ◽  
Metal Catalysts ◽  
Supported Metal Catalysts ◽  
Surface Sensitivity ◽  
Brightness Field ◽  
Backscattered Electron ◽  
Enhanced Surface ◽  
Supported Metal

AbstractThe use of a high-brightness field emission gun and novel secondary electron detection systems makes it possible to acquire nanometer-resolution surface images of bulk materials, even at low electron beam voltages. The advantages of low-voltage SEM include enhanced surface sensitivity, reduced sample charging on non-conducting materials, and significantly reduced electron range and interaction volume. High-resolution images formed by collecting the backscattered electron signal can give information about the size and spatial distribution of metal nanoparticles in supported catalysts. Low-voltage XEDS can provide compositional information of bulk samples with enhanced surface sensitivity and significantly improved spatial resolution. High-resolution SEM techniques enhance our ability to detect and, subsequently, analyze the composition of nanoparticles in supported metal catalysts. Applications of high-resolution SEM imaging and microanalysis techniques to the study of industrial supported catalysts are discussed.

C-H bond functionalization using Pd and Au supported catalysts with mechanistic insights of the active species

Synthesis ◽  
2021 ◽  
Author(s):  
Tamao Ishida ◽  
Zhenzhong Zhang ◽  
Haruno Murayama ◽  
Eiji Yamamoto ◽  
Makoto Tokunaga
Keyword(s):  
Aromatic Compounds ◽  
Reaction Mechanisms ◽  
Bond Activation ◽  
Supported Catalysts ◽  
Metal Catalysts ◽  
Active Species ◽  
Supported Metal Catalysts ◽  
Bond Functionalization ◽  
Bond Forming ◽  
Supported Metal

The C–H functionalization has been extensively studied as a direct C–C bond forming reaction with high atomic efficiency. The efforts have also been made on the reaction using supported catalysts, which are superior in terms of catalyst separation from the reaction mixture and reusability. In this review, an overview of the C–H functionalization reactions, especially for Pd and Au supported catalysts will be described. In particular, we discuss reaction mechanisms, active species, leaching, reusability, etc. 1 Introduction 2 Types of supported metal catalysts and their active species 3 Modes of C–H bond activation 4 Oxidative C–H C–H coupling of aryl compounds 5 C–H C–H coupling where one side is aromatic 6 C–H acylation of aromatic compounds and related reactions 7 Conclusion

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