In-situ immobilization and pyrolysis of metal-organic framework supported on biomorphic layered double hydroxides as highly active and stable heterogeneous catalyst

Abstract

Abstract In recent years, the pyrolysis of metal-organic frameworks (MOFs) has been widely employed to prepare advanced heterogeneous catalysts. However, large size or agglomeration caused by pyrolysis severely limits the performance of the catalysts due to the high mass transfer resistance. In this work, MOF crystals (Cu-BTC) in-situ grown on the biomorphic hierarchical layered double hydroxides (LDHs) surface (ZnAl-LDH/Cu-BTC) and it as a pyrolytic precursor to prepare layered double oxides/metal (ZnAl-LDO/Cu) composite catalyst were reported. ZnAl-LDH support induced the uniform distribution of nano-sized Cu-BTC on the nanosheets surface, and this unique method mediated Cu-BTC precursor for the in-situ construction of highly stable Cu nanoparticles under a high-temperature H2 reduction. ZnAl-LDO/Cu exhibited excellent catalytic activity and stability for the reduction 4-nitrophenol (4-NP) in the presence of NaBH4, which could be recycled for fifteen successive cycles with a high reduction efficiency (over 93%). Meanwhile, the ZnAl-LDO/Cu demonstrated high catalytic efficiencies on rhodamine B, congo red, methyl orange and methylene blue dyes. Hence, the concept presented in this work can be further expanded to synthesis of other MOFs derived high-efficiency non-noble metal catalysts, which have a great potential as a cost-effective and environmentally-friendly reusable catalyst to replace noble metals catalyst in large scale catalytic application.