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

Abstract

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 (Rct + Rad) for 15% GRP/PLA and 15% CNF/PLA 3D electrodes were found to be around 1465 and 9135 Ω cm2, 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).