RuCo alloys anchoring on hierarchical oxidized CNT architectures with boosted catalytic activity for water splitting

Abstract

Exploring cost-competitive electrocatalysts with enhanced catalytic activity is important for producing clean energy via water-splitting, including hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, RuCo alloy nanoparticles uniformly anchoring on oxidized carbon nanotube architectures (RuCo-OCA) have been constructed via ozonation, freeze-drying and thermal activation methods. RuCo-OCA exhibits excellent catalytic HER and OER performance. To reach a current density of 10 mA cm−2, RuCo-OCA requires low overpotential of 42 and 258 mV for HER and OER with the Tafel slope of 32.8 and 65.9 mV dec−1 in 1 M KOH, respectively. Meanwhile, RuCo-OCA shows negligible change of current density after chronoamperometry test for 10 h with low charge transfer resistance of 15.9 and 96 Ω for HER and OER. Furthermore, the symmetric RuCu-OCA||RuCu-OCA electrolyzer shows superior water-spitting performance to Pt/C/||RuO2 electrolyzer with a potential of 1.56 V at 10 mA cm−2. The excellent electrocatalytic performance of RuCo-OCA can be attributed to the hierarchical structure of oxidized CNT aerogel for the improved reaction kinetics and the formation of RuCo alloys with the modified electronic structure and adsorbability of intermediates. Meanwhile, the boosted active sites have been probed by density function theory. The coupling of RuCo alloys with conductive oxidized CNT aerogel can provide a new strategy to further expedite the electrocatalytic efficiency and activity of catalysts for water splitting.