Abstract: An electrochemical sensor comprising an array of working electrodes made of noble metals, wherein the array includes: one or more bare working electrode(s); and a first set of working electrodes coated with a first transition metal dichalcogenide, the first set comprises at least subset A and subset B, wherein working electrodes of subset B show the presence of hydroxide form(s) and/or high oxidation state oxide forms(s) of the noble metal, whereas working electrodes of subset A are free of such forms; and/or working electrodes of subset B show higher capacitive currents and lower charge transfer resistance compared to working electrodes of subset A, as determined by electrochemical impedance spectroscopy.

Abstract: An electrochemical microsensor comprising an array of working microelectrodes, the working microelectrodes include: one or more bare microelectrodes; one or more thick film-coated microelectrodes, optionally with conductive additive incorporated into the coating, selected from the group consisting of polysaccharide-coated microelectrodes and platinum black-coated microelectrodes; one or more thin film-coated microelectrodes selected from the group consisting of reduced graphene oxide-coated microelectrode and transition metal chalcogenide-coated microelectrodes; wherein the electrochemical microsensor further comprises a counter electrode and optionally one or more reference microelectrode(s).