Catalytic glycerol dehydration provides a sustainable route to produce acrolein because glycerol is a bioavailable platform chemical. However, in this process catalysts are rapidly deactivated due to coking. This paper examines and discusses recent insights into coking of catalysts during catalytic glycerol dehydration. The nature and location of coke and the rate of coking depend on feedstock, operating conditions, and the acidity and pore structure of the solid catalysts. Several methods have been suggested for inhibiting the coking and slowing the deactivation of catalyst, including (1) cofeeding of oxygen, (2) tuning of the pore size of the solid acid catalysts, (3) doping noble metals (Ru, Pt, Pd) into the solid acid catalysts, and (4) designing new reactors. The present methods for inhibiting coking are still unsatisfactory. The deactivated catalysts can be regenerated by removing coke. Nevertheless, the rapid deactivation of the regenerated catalyst remains problematic. The literature survey indicates that the exact chemical compositions of the coke on the catalyst during glycerol dehydration remain elusive. The thermodynamics, kinetics, and mechanism of coking need to be probed so as to advance the development of a catalyst with high activity, selectivity, and resistance to coking to put the catalytic glycerol dehydration into practice.

Modification of saponite (Sap) by surface engineering and intercalation chemistry introduces guest species into the structure of Sap and enhances the functionalities of the resultant Sap-based hybrids or composites. This review summarizes and evaluates latest scientific advances in the strategies for surface engineering, intercalation and hybridization of Sap, the insights into the relevant mechanisms, and the properties and applications of the resultant Sap-based materials. Studies have indicated that Sap can be inorganically modified by acid activation, inorganic cation exchange, pillaring, and adsorption. The methods of preparing organo-saponite (OSap) hybrids can be categorized as follows: 1) exchanging the inorganic cations in the interlayer space of Sap with organic cations; 2) covalent grafting of organic moieties or groups onto the surface of Sap; 3) intercalating polymer into the interlayer space of Sap by solution intercalation, and melt mixing or in situ polymerization. Organic-inorganic modified Sap can be made through the reactions between organic species and inorganic-modified Sap, or by the combination of inorganic species with organic-modified Sap. Modified Sap exhibits exceptional thermal stability, surface acidity, optical effects and adsorption. As such, the modified Sap can be used for optical materials, adsorbents, catalysts and clay/polymer nanocomposites (CPN). Literature survey suggests that future studies should place emphasis on optimizing and scaling up the modification of Sap, probing the thermodynamics, kinetics and mechanisms of the modification of Sap, endowing Sap with novel functionalities, and accordingly advancing the practical applications of the resultant Sap-based materials.

As a stable and efficient energy storage device, supercapacitor has attracted extensive attention due to its superior power density. However, developing multifunctional supercapacitors with high flexibility and strong environmental adaptability...

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