Au-nanoparticle loaded nickel-copper bimetallic MOF: An excellent catalyst for chemical degradation of Rhodamine B

Abstract Synthesis, characterization and catalytic performance of Au-nanoparticle (NP) functionalized Nickel-Copper bimetallic three-dimensional MOF is presented. A three dimensional bimetallic MOF involving aromatic polycarboxylate ligands viz. benzene 1,4-dicarboxylate and benzene 1,3,5-tricarboxylate as linkers with Cu (II) and Ni (II) as metal nodes was synthesized through Solvothermal method. Structural and morphological studies of the as-synthesized material were carried out by FTIR, PXRD, SEM and TEM analysis. The elemental composition of the material was established by EDS mapping. Thermal stability of the as-prepared samples was tested by TGA analysis. The characterization details well establish the synthesis of first of its kind of bimetallic mixed metal–ligand MOF composed of nickel and copper metal ions trapped in an organic framework of bipodal and tripodal carboxylate based mixed ligands. The bimetallic MOF was successfully functionalized by Au NPs and was tested for its catalytic performance toward the chemical degradation of environmentally hazardous organic pollutant Rhodamine B. Compared to the pristine MOF, the Au doped MOF exhibited an exceptionally high catalytic activity (kapp = 13.74 × 10−2 min−1) and thermal stability, which can be attributed to the functional synergism prevailing between the Au nanoparticles and the three-dimensional bimetallic mixed ligand framework. The estimated kapp value for RhB degradation is significantly better than those reported for various state of the art nanocomposite catalysts reported in the recent past.