Title : Surface engineered : Noble metal nanoparticle incorporated natural diatom biosilica catalyst for oxidation of D glucose
Diatoms, unicellular photosynthetic algae that occur in all water territories on earth. Their cell walls are composed of amorphous biosilica also called frustule. They exhibit nanoporous to microporous and macroporous patterning that is specific to particular species. Attributable to their highly porous structure, diatom biosilica is a promising renewable material for various applications such as catalysis, drug delivery systems, and bio-photonics. These are highly potent siliceous materials these days due to excellent biocompatibility, low cost and ease of surface modification.
Catalysis is an important technology for industrial production of chemicals and various biotechnological reactions. Heterogeneous catalysis is particularly advantageous because the separation of the catalyst from the reaction products is effortless and easy. Therefore, the exploration of more suitable catalyst supports has become ever more vital over the last few decades. Diatom biosilica can be a suitable candidate as catalyst support material due to its porous structure and also naturally available for sustainable catalytic solutions.
In the current work, the properties of diatom (Aulocoseira sp.) were surface functionalized with thiol groups and decorated with silver and gold nanoparticles. Diatoms biosilica (DE) as catalyst supports and two series of synthesized catalysts DE-SH-AuNP and DE-SH-AgNP were characterized by various spectroscopic techniques such as FT- IR, SEM, EDAX, XRD and BET surface area analysis. DE as catalyst supports and the synthesized catalysts DE-SH-AuNP and DE-SH-AgNP were investigated for oxidation of D-glucose to D-gluconic acid. D-gluconic acid is an important chemical intermediate in the pharmaceutical industry, food industry and also useful in paper and concrete production. Diatom biosilica showed very high nanoparticle-loading (AgNP and AuNP) capacities with a homogeneous nanoparticle distribution. The catalysts exhibited higher activity in for oxidation of D-glucose.