Graphene-oxide-bacterial-cellulose nanohybrid gives a “substrate-driven enhancement” effect to catalytic activity of phthalocyanine

The understanding of interaction between graphene oxide (GO) and bacterial cellulose (BC) at molecular level is indispensable for meeting the goal of constructing a graphene-oxide-bacterial-cellulose (GOBC) nanohybrid and the fabrication of GOBC-based functional nanocomposites. In this paper, a GOBC with hierarchical three-dimensional (3D) framework was designed as a substrate for the metal phthalocyanine (Pc) catalyst. This substrate caused a remarkable enhancement of the catalysis of organic dye molecules. Firstly, GOBC was conveniently fabricated with one-step biosynthesis. The interaction mechanism at the molecular level between GO and BC was modeled with DFT quantum mechanics calculations that followed semi-empirical molecular dynamics studies to propose a structure. The formation of hydrogen-bond between O(3)-H and O(6)-H of BC and oxygen atom of GO was verified by core valence bifurcation and revealing noncovalent interactions theoretical analysis. Graphene-bacterial-cellulose (GBC) nanohybrid was then prepared by brief reduction of GOBC with N₂H₄ and used for the direct immobilization of Pc catalyst. The catalytic activity of the Pc that was immobilized on the GBC nanohybrid was evaluated based on its catalytic oxidation of organic dyes, and a remarkable enhancement of the catalytic activity by the GBC substrate was observed. The electron transfer and the electrical structure state of the catalytic system were investigated by charge density difference and density of states theoretical calculations. An innovative catalytic mechanism of “substrate-driven enhancement” of the highly reactive metal phthalocyanine immobilized graphene-bacterial-cellulose nanocomposite was proposed based on both experimental and theoretical calculation results.