UV/VIS spectroelectrochemistry with 3D printed electrodes

Recent years have witnessed a boom in applying 3D printing technologies to manufacture customized prototypes in various fields of science. In electrochemistry, fused deposition modelling (FDM) 3D printing employing composite filaments based on thermoplastic materials and conductive allotropes of carbon enabled rapid, routine, inexpensive and operationally safe fabrication of conductive electrodes. Nevertheless, results of cyclovoltammetric measurements reported in the literature indicate that 3D printed electrodes give rise to considerable intrinsic kinetic barriers for electron transfer through the electrode/electrolyte interface. In this work we employ FDM-based 3D printing followed by a simple anodic activation procedure to manufacture electrodes from commercially available composites of polylactic acid (PLA) and carbon nanotubes (CNTs). Employing cyclic voltammetry with ruthenium(III) acetylacetonate as the electroactive probe we demonstrate that the previously reported kinetic barrier is almost completely removed upon the activation process. We apply such devised procedure to manufacture electrodes with optical windows allowing UV/VIS absorption spectroscopic detection of electrogenerated products. We are thus the first to perform a UV/VIS absorption spectroelectrochemical experiment employing 3D printed optically transparent working electrodes. [Display omitted]