Title

Unzipping MWCNTs for controlled edge- and heteroatom-defects in revealing their roles in gas-phase oxidative dehydrogenation of ethanol to acetaldehyde

Document Type

Journal Article

Publication Title

Chemical Engineering Journal

Volume

446

Publisher

Elsevier

School

School of Science

Funders

Fundamental Research Funds for the Central Universities (Special Project of Civil Aviation University of China, No. 3122021062) / National Natural Science Foundation of China (No. 51425302, 51702062) / Australian Research Council (No. DP190103548), partial support

Grant Number

ARC Number : DP190103548

Grant Link

http://purl.org/au-research/grants/arc/DP190103548

Comments

Yang, Q., Huang, X., Zhang, J., Xiao, Z., Duan, X., Zhou, S., ... & Wang, S. (2022). Unzipping MWCNTs for controlled edge-and heteroatom-defects in revealing their roles in gas-phase oxidative dehydrogenation of ethanol to acetaldehyde. Chemical Engineering Journal, 446, 3, 137150. https://doi.org/10.1016/j.cej.2022.137150

Abstract

Bioethanol is a promising candidate for acetaldehyde production. In this study, we controllably unzipped multi-walled carbon nanotubes into open-edged nanotube/nanoribbon hybrids via a nano-cutting strategy for metal-free oxidative dehydrogenation of ethanol to acetaldehyde and unravelled the catalytic role of edge defects in the reaction. The edge-rich structure of the 1D-nanotube/2D-nanoribbon hybrid can accelerate the catalytic reaction more efficiently than pristine carbon sample. Moreover, edges can further accommodate nitrogen defects to preferentially form edge-doped nitrogen. Through engineering the concentration and speciation of defects, the structure-performance relationship between the defective structure and ethanol conversion rate is intensively investigated. Theoretical calculations unveil that the nitrogen doped at edge sites other than in basal planes can effectively facilitate O2 dissociation and formation of oxygen-containing active centers. Temperature-programmed ethanol desorption and kinetic measurements further supplement the catalytic interplay of edge and nitrogen defects on ethanol adsorption and reaction kinetics. The synergistic edge and nitrogen defects of the engineered hybrid produced a steady ethanol conversion of 47.9% and acetaldehyde selectivity of 90.2% at the gas hourly space velocity of 48,000 mL gcat-1h−1 on stream of 48 h. This work offers more insights to intrinsic properties and mechanism of enriched defective structures for development of effective carbocatalysts in catalytic applications.

DOI

10.1016/j.cej.2022.137150

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