A systematic study on the use of biogenic acids in directing the hyperbranched growth of Au nanocorals

Morphology is a critical factor that defines the properties and functions of nanomaterials. For gold (Au) nanostructures, branched morphological features have been proven to be beneficial in improving their properties and expanding their potential application domains. One notable example are Au nanocorals, whose elaborate hyperbranched architecture has been shown to result in enhanced performance in SERS-based detection, fluorescence imaging, and catalysis. However, due to their complex morphological design, their fabrication often necessitates complicated synthetic procedures, long reaction times, and harsh and/or expensive reagents. In this work, we present an alternative synthetic approach by which Au nanocorals are conveniently and rapidly produced in water under ambient conditions using low-cost biogenic acids. Through systematic evaluation of select biogenic acids, the key functional groups that are instrumental in the formation of a hyperbranched architecture were identified. From the results of our study, we were able to build a list of biogenic reagents (ascorbic acid, oxalic acid, gallic acid, protocatechuic acid, and succinic acid) that can be employed for the green and facile production of Au nanocorals. The ability to synthesize hyperbranched Au nanocorals using a simple, green, rapid, and economical approach is projected to spur further interest in these intricately designed materials and open up new avenues for their applications in various fields.