Silver nanoparticles modified electrodes for electroanalysis: An updated review and a perspective

The interest in the use of silver nanoparticles (Ag NPs) in electroanalysis is extensive reflecting their biological, thermal, optical and catalytic properties. Over the last two decades, besides commercially available Ag NPs, enormous research has been conducted on developing new approaches for the synthesis, characterization and improving the sensing performance of nano silver towards numerous targets. In this review, we exclusively focus on the recent advances reported on the preparation of Ag NPs-based electrodes and their application in electroanalysis from 2010 onward. Importantly, this review provides answers to critical questions such as ‘are there advantages of Ag NP-based electrodes over unmodified electrodes or silver macroelectrodes’ and ‘if there is an improvement what is the physicochemical basis for this?’. This bottom-up approach is key to understand the electrochemical behaviour of NPs and the motifs of electrode modifications and thus provides a useful guide for electrochemists to develop novel electrochemical sensors. In addition to conventional electrode modification approaches such as drop casting and dip coating using ensembles of NPs, this review discusses the single particle electrochemistry (nano-impacts) method, which is currently emerging as an ultrasensitive tool for nanoparticles characterization and detection of analytes at the single particle level. In addition, challenges and future perspectives for improving the performance of Ag NPs-based electrodes in sensing and electroanalysis are outlined.