Controlled formation of porous CuCo2O4 nanorods with enhanced oxidase and catalase catalytic activities using bimetal-organic frameworks as templates

Porous structures with highly dispersed and active catalytic sites are vital to improve the catalytic activity and stability of artificial enzyme-related catalytic reactions. Herein, a novel nanorod-like bimetal-organic framework serving as porous support and supplier of Co 2+ and Cu 2+ was used to prepare a beneficial porous metal oxide. By optimizing the calcination temperature, the composition of calcined product can be controlled and the nanorods with isolated and highly active CuCo 2 O 4 nanoparticles were obtained. The porous CuCo 2 O 4 nanorods exhibit a pH-dependent catalytic property, that is, they behave as oxidase in acid conditions and catalase in alkaline conditions. The CuCo 2 O 4 nanorods perform dual-enzyme catalytic activity superior to monometallic oxides. What’s more, compared with the reported Co 3 O 4 nanoparticles, Co 3 O 4 /CuO hollow nanocage hybrids and NiCo 2 O 4 mesoporous spheres, the porous CuCo 2 O 4 nanorods show higher affinity to 3,3′,5,5′-tetramethylbenzidine with a lower K m value. The superior dual-enzyme catalytic activities of CuCo 2 O 4 nanorods benefit from the high catalytic activity of binary metal oxides and structural stability. After incubating in a wide range of pHs, temperatures and ionic strengths, the catalytic activity of CuCo 2 O 4 nanorods can be maintained. The oxidase activity of CuCo 2 O 4 nanorods can be inhibited in the presence of ascorbic acid, which can be applied in effective detection of ascorbic acid. This study opens a new path to prepare stable and highly active porous artificial enzymes.