The synergistic catalysis on Co nanoparticles and CoNx sites of aniline-modified ZIF derived Co@NCs for oxidative esterification of HMF

• Published in: Chinese chemical letters Vol. 32; no. 2; pp. 685 - 690
• Main Authors: Rui, Tao, Lu, Guo-Ping, Zhao, Xin, Cao, Xun, Chen, Zhong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2021; School of Chemical Engineering, Nanjing University of Science & Technology, Nanjing 210094, China%School of Chemical Engineering, Nanjing University of Science & Technology, Nanjing 210094, China; School of Materials Science & Engineering, Nanyang Technological University, Singapore 639798, Singapore%School of Materials Science & Engineering, Nanyang Technological University, Singapore 639798, Singapore
• Subjects: 5-Hydroxymethylfurfural; Aniline-modified ZIF; Oxidative esterification; Porous cobalt/nitrogen co-doped carbon; Synergistic catalysis on CoNx sites and Co nanoparticles; 5-Hydroxymethylfurfural; Aniline-modified ZIF; Porous cobalt/nitrogen co-doped carbon; Synergistic catalysis on CoNx sites and Co nanoparticles; Oxidative esterification; Synergistic catalysis on CoNx sites and Co; nanoparticles
• ISSN: 1001-8417; 1878-5964
• DOI: 10.1016/j.cclet.2020.06.027

Aniline-modified ZIF derived Co/N codoped carbon: Co@NC-PhA-3 can achieve base-free oxidative esterification of HMF under ambient conditions due to its higher specific surface area, the protective carbon shell of smaller Co NPs and higher N content. Furthermore, a synergistic catalytic effect between CoNx sites and Co NPs has also been disclosed. [Display omitted] An efficient, sustainable and scalable strategy for the synthesis of porous cobalt/nitrogen co-doped carbons (Co@NCs) via pyrolysis of aniline-modified ZIFs, has been demonstrated. Aniline can coordinate and absorb on the surface of ZIF (ZIF-CoZn3-PhA), accelerate the precipitation of ZIFs, thus resulting in smaller ZIF particle size. Meanwhile, the aniline on the surface of ZIF-CoZn3-PhA promotes the formation of the protective carbon shell and smaller Co nanoparticles, and increases nitrogen content of the catalyst. Because of these properties of Co@NC-PhA-3, the oxidative esterification of 5-hydroxymethylfurfural can be carried out under ambient conditions. According to our experimental and computational results, a synergistic catalytic effect between CoNx sites and Co nanoparticles has been established, in which both Co nanoparticles and CoNx can activate O2 while Co nanoparticles bind and oxidize HMF. Moreover, the formation and release of active oxygen species in CoNx sites are reinforced by the electronic interaction between Co nanoparticles and CoNx.