Preparation of Gold Nanoplates Using Ortho Carbonyl Compounds as Capping Agents for Electrochemical Sensing of Lead Ions

In this study, gold nanoplates were synthesized using plant molecules (gallic acid) following a kinetic control mode. The growth of nanoplates is mainly due to the specific adsorption of capping agents on certain crystal facets. Through systematical characterizations, it is found that the distance between two oxygen atoms in ortho carbonyl compounds matches well with the lattice spacing of gold (111) facets exactly, which is beneficial to the formation of twin seeds and further the growth of plate-like gold nanoparticles. The gold nanoplates on glassy carbon electrode show a remarkably improved electrochemical sensing activity of lead ions compared to the bare glassy carbon electrode or spherical gold nanoparticle-modified electrode. The modified electrode is expected to be used in the detection of lead ion concentration in heavy metal wastewater.