Sivakumar Balakrishnan

In this study, new composite materials comprising zeolitic imidazolate framework (ZIF) structures and microchannel glass (MCG) plates were fabricated using the hydrothermal method and their morphological and spectral properties were investigated using XRD, SEM, FTIR, and Raman spectroscopy. XRD studies of powder samples revealed the presence of an additional phase for a ZIF-8 sample, whereas ZIF-67 samples, which were prepared through two different chemical routes, showed no additional phases. A detailed analysis of the FTIR and micro-Raman spectra of the composite samples revealed the formation of stable ZIF structures inside the macropores of the MCG substrate. The hydrophilic nature of the MCG substrate and its interaction with the ZIF structure resulted in the formation of stable ZIF-MCG composites. We believe that these composite materials may find a wide range of important applications in the field of sensors, molecular sieving.

In this work, the electrochemical etching of p-type silicon was performed in aqueous ethanol-surfactant solutions and the dependence of morphology and luminescent properties of porous silicon with respect to the etching parameters and silicon resistivities have been studied. The obtained porous silicon structures have been studied using various characterisation techniques such as SEM (Scanning Electron Microscopy) and Photoluminescence (PL) spectroscopy.

Thin films of vapor-phase polymerized PEDOT incorporating various cationic Mn porphyrins were assessed for water oxidation catalysis under light illumination. Only Mn(III)TPP/PEDOT displayed a notable photocurrent and this was, counter-intuitively, greatest at the lowest loading levels examined. Studies revealed that a proportion of the Mn(III)TPP within the PEDOT became demetalated during polymerization, leaving free and protonated TPP. Despite the presence of an excess of chemical oxidant during the polymerization step, the Mn(III) ion was reduced — likely under the influence of light — to Mn(II), which was labilized out of the film. Whereas PEDOT films loaded with anionic Mn porphyrins may be active and selective water oxidation photocatalysts, their analogs containing cationic Mn porphyrins, like Mn(III)TPP, are catalytically inert.

Methods for the growth of the metal–organic framework (MOF) HKUST-1 on bulk glassy carbon have been developed.