Fabrication of 3D-printed graphene/polylactic acid and carbon nanofiber/polylactic acid electrodes: New solvent-free electrochemical activation method for hydrogen evolution reactions

In this study, polylactic acid (PLA) composites containing different ratios (5%-15%) of graphene (GRP) and carbon nanofiber (CNF) were filamented using an extruder and then, 3D printed electrodes were produced by fused deposition modeling (FDM) method using the obtained GRP-PLA and CNF-PLA based filaments. The Electrochemical measurements of the 3D electrodes toward the hydrogen evolution reaction (HER) were investigated. According to the results obtained from the cathodic curves; It was determined that the current densities of 15% GRP/PLA and 15% CNF/PLA 3D electrodes were higher than the other electrodes and these values were around 0.325 and 0.329 mA cm(-2), respectively. From the EIS results, the resistance values (R-ct + R-ad) for 15% GRP/PLA and 15% CNF/PLA 3D electrodes were found to be around 1465 and 9135 ? cm(2), respectively. It was determined that these two 3D electrodes had the lowest resistance values compared to other ratios. To increase the efficiency for HER, after soaking in 1 M KOH for 1 h, the activation process was carried out using the CV method by taking 100 cycles in the 0/-3 V range. The results were compared with the activation method reported in the literature (DMF and 2.5 V electrochemical treatment).