Nitrogen-Doped Graphene Nanosheets as Metal-Free Catalysts for Aerobic Selective Oxidation of Benzylic Alcohols

详细信息    查看全文

• 作者：Jinlin Long ; Xiuqiang Xie ; Jie Xu ; Quan Gu ; Liming Chen ; Xuxu Wang
• 刊名：ACS Catalysis
• 出版年：2012
• 出版时间：April 6, 2012
• 年：2012
• 卷：2
• 期：4
• 页码：622-631
• 全文大小：598K
• 年卷期：v.2,no.4(April 6, 2012)
• ISSN：2155-5435

文摘

This work demonstrates the molecular engineering of active sites on a graphene scaffold. It was found that the N-doped graphene nanosheets prepared by a high-temperature nitridation procedure represent a novel chemical function of efficiently catalyzing aerobic alcohol oxidation. Among three types of nitrogen species doped into the graphene lattice鈥攑yridinic N, pyrrolic N, and graphitic N鈥攖he graphitic sp² N species were established to be catalytically active centers for the aerobic oxidation reaction based on good linear correlation with the activity results. Kinetic analysis showed that the N-doped graphene-catalyzed aerobic alcohol oxidation proceeds via a Langmuir鈥揌inshelwood pathway and has moderate activation energy (56.1 卤 3.5 kJ路mol^鈥? for the benzyl alcohol oxidation) close to that (51.4 kJ路mol^鈥?) proceeding on the catalyst Ru/Al₂O₃ reported in literature. An adduct mechanism was proposed to be different remarkably from that occurring on the noble metal catalyst. The possible formation of a sp² N鈥揙₂ adduct transition state, which can oxidize alcohols directly to aldehydes without any byproduct, including H₂O₂ and carboxylic acids, may be a key element step. Our results advance graphene chemistry and open a window to study the graphitic sp² nitrogen catalysis.

Keywords:

graphene; nitrogen doping; nonmetal catalysis; selective oxidation; alcohols; aldehydes