Facet dependent catalytic activity of Pd nanocrystals for the remedy of organic Pollutant: A mechanistic study

Abstract

The facet effect and underlying molecular mechanisms of Palladium (Pd) nanocrystals have shown a potential candidate for various applications including catalysis and organic pollutant remediation. In this report, seed mediated synthesis was used to synthesize three distinct Pd nanostructures such as cuboctahedral (Coh), octahedral (Oh), and nanocubes (NCs) by optimizing the time and the temperature. The growth of nanocrystals were directed along different low index planes such as {100} for Pd NCs, {111} for Oh, and mixed planes of {100} and {111} for Coh. To understand the facet dependent catalysis, nanocrystals were employed for the reduction of 4-Nitroaniline (4-NA) to 4-Phenylenediamine (4-PDA), studied the effect of NO2 group and the degradation of cationic dye, Rhodamine B (RhB), and anionic dye, Methyl Orange (MO). By keeping the total surface area of particles unchanged, different volume of nanocrystal solutions were used to carry out facet-dependent analysis. The reduction and degradation processes were confirmed from the absorption study that the efficiency of Pd NCs was higher than Oh and Coh. The catalytic trends for the asymmetric growth of planes follows the order of NCs {100} > Oh {111} > Coh {100} {111}. The specific reactivity performance of the nanocrystals were confirmed using an analytical model.