Zihao Zhang1,2,3, Siyu Yao1, Xiaobing Hu4,5, Francis Okejiri2,3, Kun He4,5, Pingying Liu6, Ziqi Tian6, Vinayak P Dravid4,5, Jie Fu1,7, Xiang Zhu8, Sheng Dai3,2. 1. Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering Zhejiang University Hangzhou 310027 China. 2. Department of Chemistry The University of Tennessee Knoxville TN 37996 USA. 3. Chemical Sciences Division Oak Ridge National Laboratory Oak Ridge TN 37831 USA. 4. Department of Materials Science and Engineering Northwestern University Evanston IL 60208 USA. 5. The NUANCE Center Northwestern University Evanston IL 60208 USA. 6. Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo Zhejiang 315201 China. 7. Institute of Zhejiang University - Quzhou 78 Jiuhua Boulevard North Quzhou 324000 China. 8. State Key Laboratory for Oxo Synthesis and Selective Oxidation, Suzhou Research Institute of Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 China.
Abstract
High-temperature pyrolysis of nitrogen (N)-rich, crystalline porous organic architectures in the presence of a metal precursor is an important chemical process in heterogeneous catalysis for the fabrication of highly porous N-carbon-supported metal catalysts. Herein, covalent triazine framework (CTF) and CTF-I (that is, CTF after charge modulation with iodomethane) are presented as sacrificial templates, for the synthesis of carbon-supported Ru catalysts-Ru-CTF-900 and Ru-CTF-I-900 respectively, following high-temperature pyrolysis at 900 °C under N2 atmosphere. Predictably, the dispersed Ru on pristine CTF carrier suffered severe sintering of the Ru nanoparticles (NPs) during heat treatment at 900 °C. However, the Ru-CTF-I-900 catalyst is composed of ultra-small Ru NPs and abundant Ru single atoms which may have resulted from much stronger Ru-N interactions. Through modification of the micro-environment within the CTF architecture, Ru precursor interacted on charged-modulated CTF framework shows electrostatic repulsion and steric hindrance, thus contributing toward the high density of single Ru atoms and even smaller Ru NPs after pyrolysis. A Ru-Ru coordination number of only 1.3 is observed in the novel Ru-CTF-I-900 catalyst, which exhibits significantly higher catalytic activity than Ru-CTF-900 for transfer hydrogenation of acetophenone.
High-temperature pyrolysis of nitrogen (n class="Chemical">N)-rich, crystalline porous organic architectures in the presence of a metal precursor is an important chemical process in heterogeneous catalysis for the fabrication of highly porous N-carbon-supported metal catalysts. Herein, covalent triazine framework (CTF) and CTF-I (that is, CTF after charge modulation with iodomethane) are presented as sacrificial templates, for the synthesis of carbon-supported Ru catalysts-Ru-CTF-900 and Ru-CTF-I-900 respectively, following high-temperature pyrolysis at 900 °C under N2 atmosphere. Predictably, the dispersed Ru on pristine CTF carrier suffered severe sintering of the Ru nanoparticles (NPs) during heat treatment at 900 °C. However, the Ru-CTF-I-900 catalyst is composed of ultra-small RuNPs and abundant Ru single atoms which may have resulted from much stronger Ru-N interactions. Through modification of the micro-environment within the CTF architecture, Ru precursor interacted on charged-modulated CTF framework shows electrostatic repulsion and steric hindrance, thus contributing toward the high density of single Ru atoms and even smaller RuNPs after pyrolysis. A Ru-Ru coordination number of only 1.3 is observed in the novel Ru-CTF-I-900 catalyst, which exhibits significantly higher catalytic activity than Ru-CTF-900 for transfer hydrogenation of acetophenone.
Authors: Zhigang Geng; Yan Liu; Xiangdong Kong; Pai Li; Kan Li; Zhongyu Liu; Junjie Du; Miao Shu; Rui Si; Jie Zeng Journal: Adv Mater Date: 2018-08-10 Impact factor: 30.849