Simple anodization of home-made screen-printed carbon electrodes makes significant activity enhancement for hydrogen evolution: the synergistic effect of surface functional groups, defect sites, and hydrophilicity

Undoubtedly, electrocatalyzing the hydrogen evolution reaction (HER) is now becoming the subject of extensive studies due to its crucial role in harvesting clean energy. In general, bare screen-printed carbon electrodes (SPCEs) have negligible ability to catalyze the HER due to the lack of effective sites. Here we find that: 1) a facile anodization treatment can improve the electrocatalytic activity of home-made SPCEs with apparently reduced overpotential and increased current density for the HER; 2) the activity enhancement of SPCEs is highly dependent on anodization conditions including electrolyte, treatment time, and anodization potential; 3) the introduction of negatively charged oxygen-containing functional groups during anodization, together with the increased defect sites and hydrophilicity on electrode surface, leads to the promoted activity of anodized SPCEs synergistically. Similar phenomena are also found in other carbon-based electrodes including glassy carbon electrode and carbon nanotube-modified electrode. These findings reported in this work are expected to guide the future design of advanced electrode systems for efficient hydrogen evolution. (C) 2017 Elsevier Ltd. All rights reserved.