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Gold nanoparticles have been deposited on synthetic calcite substrate by galvanic displacement reaction and electroless deposition methods. A comparative study has shown that electroless deposition is superior compared to galvanic displacement reaction for uniform deposition of gold nanoparticles on calcite. Characterization of the samples, prepared by two different deposition methods, was carried out by X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy (FE-SEM) and diffuse reflectance spectroscopy (DRS) measurements. FE-SEM studies prove that smaller nanoparticles of gold are deposited uniformly on calcite if electroless deposition method was employed and DRS measurements show the characteristic surface plasmon resonance of gold nanoparticles.

ZnO nanoparticles have been deposited on calcite via a simple chemical method and their optical properties and photocatalytic activity have been investigated. The ZnO nanoparticles were deposited on calcite by pre-treatment of the calcite surface with zinc acetate followed by ZnO deposition. Pre-treatment of the calcite was found to be necessary for the uniform deposition of ZnO nanoparticles. Various deposition parameters such as concentration of the reagents and deposition time were investigated. Diffuse reflectance spectroscopy studies indicate that the ZnO nanoparticles on calcite exhibit quantum size effect. Room temperature photoluminescence spectra of the samples show the near band edge emission due to ZnO nanoparticles and also the emission due to defect centers. Photocatalytic degradation of Rhodamine-B was carried out using the ZnO nanoparticles deposited calcite and the performance is comparable with that of free ZnO nanoparticles.