Morphology-controllable bimetallic gold nanostructures for mercury detection: Recent developments, challenges and prospects

Abstract

Gold bimetallic nanostructures (AuBMNS) have exhibited superior Hg sensing activity as compared to their monometallic counterparts. Moreover, the Hg sensing performance of AuBMNS depends on their shape, size, composition, and surface chemistry. Thus, morphology-controlled preparation and application of these nanostructures in Hg detection is a hot area of research. Till now, no review paper in the literature accounts for the recent advances in the morphology-controlled synthesis of AuBMNS and their application in sensing Hg related to shape, size, optimum composition, morphology, and surface ligands. Taking this into consideration, we attempt to offer a clear understanding of the shape/size-controlled preparation, functionalization, and morphology-dependent application of AuBMNS in Hg detection. The chemical reduction approach for the morphology-controlled preparation of AuBMNS is critically discussed. The prospective role of different reaction parameters such as temperature, pH, time, reducing agents, nature/concentration of precursors, and capping/stabilizing agents in the morphology-controlled preparation of these nanostructures are reviewed. Moreover, morphology-dependent optical properties and performance of AuBMNS are discussed with recent (2020–2022) examples. In the later part, detection of Hg by using AuBMNS is reviewed and the effects of size, shape, surface chemistry/structure, optimum composition, and synergism are discussed. Finally, recent challenges in morphology-controlled preparation of AuBMNS, their shape/size-dependent performance, and prospects to resolve the related issues are discussed.

Keywords

• Mercury detection
• Gold bimetallic nanostructure
• Morphology-controlled preparation
• Shape/size and sensing
• Nano-sensors for Hg