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Conformal Coating of Co/N‐Doped Carbon Layers into Mesoporous Silica for Highly Efficient Catalytic Dehydrogenation–Hydrogenation Tandem Reactions
Author(s) -
Zhang Zhujun,
Wei Xiangru,
Yao Yan,
Chen Zhi,
Zhang Aijian,
Li Wei,
Wu Winston Duo,
Wu Zhangxiong,
Chen Xiao Dong,
Zhao Dongyuan
Publication year - 2017
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201702243
Subject(s) - dehydrogenation , catalysis , materials science , mesoporous material , chemical engineering , nitrobenzene , mesoporous silica , coating , carbon fibers , graphene , inorganic chemistry , cobalt , organic chemistry , nanotechnology , chemistry , composite material , composite number , engineering , metallurgy
To maximize the utilizing efficiency of cobalt (Co) and optimize its catalytic activity and stability, engineering of size and interfacial chemical properties, as well as controllable support are of ultimate importance. Here, the concept of coating uniform thin Co/N‐doped carbon layers into the mesopore surfaces of mesoporous silica is proposed for heterogeneous aqueous catalysis. To approach the target, a one‐step solvent‐free melting‐assisted coating process, i.e., heating a mixture of a cobalt salt, an amino acid (AA), and a mesoporous silica, is developed for the synthesis of mesoporous composites with thin Co/N‐doped carbon layers uniformly coated within mesoporous silica, high surface areas (250–630 m 2 g −1 ), ordered mesopores (7.0–8.4 nm), and high water dispersibility. The strong silica/AA adhesive interactions and AA cohesive interactions direct the uniform coating process. The metal/N coordinating, carbon anchoring, and mesopore confining lead to the formation of tiny Co nanoclusters. The carbon intercalation and N coordination optimize the interfacial properties of Co for catalysis. The optimized catalyst exhibits excellent catalytic performance for tandem hydrogenation of nitrobenzene and dehydrogenation of NaBH 4 with well‐matched reaction kinetics, 100% conversion and selectivity, high turnover frequencies, up to ≈6.06 mol nitrobenzene mol Co −1 min −1 , the highest over transition‐metal catalysts, and excellent stability and magnetic separability.