Multifunctional core@shell structured gold nanodendrites@gold nanoclusters: An efficient catalytic and sensor domain for environmental remediation applications

Abstract

Over the recent decades, rapid industrialization, the excess use of chemical reagents, and their improper waste disposal to the environment caused severe damage to the ecosystem. To get rid of these serious issues, the propitious solution would be finding a multifunctional catalyst system that could detect and degrade/inactivate the poisonous pollutants released in the environment. In this regard, core@shell structured Au nanodendrites@Au nanoclusters (AuND@AuNC) were prepared by a facile one-step inverted process using methionine for pollutant degradation and heavy metal detection. There is no surfactant, polymer, or seed was employed in the preparation of AuND@AuNC. In the preparation of AuND@AuNC, the concentration of AuCl4- was optimized and it was observed that beyond 1.5 mM of Au concentration, formed gold sols aggregate immediately. Prepared AuND@AuNC were characterized well using high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction technique (SAED), X-ray diffraction (XRD), UV-Vis absorption spectroscopy, and X-ray photoelectron spectroscopy (XPS). Interestingly, the prepared AuND@AuNC demonstrates excellent catalytic reduction/degradation of nitroaromatic compounds and organic dye molecules with the aid of sodium borohydride. The results of the kinetic studies confirm the superior catalytic activity of present AuND@AuNC over already published results. Further, AuND@AuNC prepared with 1.5 mM Au concentration exhibits excellent colorimetric sensing behaviour towards cadmium ion (Cd2+) in the presence of 500 µM of interfering ions with a limit of detection of 2.5 µM. The excellent catalytic and sensing behavior of AuND@AuNC material is attributed to its unique structural features and methionine functionalization.