Toward Planar Atomic-Gold Decorated Polyaniline Gas Sensors for Enhanced Electrochemical Sensing

With the rapid advancement in complex chemical information systems and biomimetic models, the need for chemical sensors with partially overlapping selectivities has grown more than ever. Fabrication of multiple sensing films for chemical sensing is tedious, and time-consuming-newer approaches are needed. By using novel sensing materials such as noble-metal-based single-atom catalysts decorated on conducting polymers, multiple sensing films can be fabricated. In this research, bi-atomic gold (or nanostructure of two gold atoms) electrocatalyst has been successfully decorated on a polyaniline (PANI) matrix to yield sensing films capable of discriminating between propanol isomers in both liquid and gas phases. Sensor miniaturization was achieved by combining the ionic liquid electrolyte and silver–silver chloride pseudo-reference on a planar substrate. The sensor was operational with a static electrochemical potential and the sensor response with bi-atomic gold was larger than with no gold electrode. Furthermore, the sensor with bi-atomic gold showed both linear and nonlinear response curves to each of the two propanol isomers pointing to selectivity. Sensor drift is a significant issue with such pseudo-reference electrode-based sensor configuration, and alternative approaches are suggested.