TY - JOUR
T1 - Conformal coating of Co/N-doped carbon layers into mesoporous silica for highly efficient catalytic dehydrogenation–hydrogenation tandem reactions
AU - Zhang, Zhujun
AU - Wei, Xiangru
AU - Yao, Yan
AU - Chen, Zhi
AU - Zhang, Aijian
AU - Li, Wei
AU - Wu, Winston Duo
AU - Wu, Zhangxiong
AU - Chen, Xiao Dong
AU - Zhao, Dongyuan
PY - 2017/11/13
Y1 - 2017/11/13
N2 - 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 m2 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 NaBH4 with well-matched reaction kinetics, 100% conversion and selectivity, high turnover frequencies, up to ≈6.06 molnitrobenzene molCo −1 min−1, the highest over transition-metal catalysts, and excellent stability and magnetic separability.
AB - 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 m2 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 NaBH4 with well-matched reaction kinetics, 100% conversion and selectivity, high turnover frequencies, up to ≈6.06 molnitrobenzene molCo −1 min−1, the highest over transition-metal catalysts, and excellent stability and magnetic separability.
KW - cobalt catalysts
KW - conformal coating
KW - mesoporous materials
KW - nitrogen-doped carbon
KW - tandem dehydrogenation/hydrogenation
UR - http://www.scopus.com/inward/record.url?scp=85030213987&partnerID=8YFLogxK
U2 - 10.1002/smll.201702243
DO - 10.1002/smll.201702243
M3 - Article
C2 - 28940901
AN - SCOPUS:85030213987
VL - 13
JO - Small
JF - Small
SN - 1613-6810
IS - 42
M1 - 1702243
ER -