Carbon Nanotube Support, Carbon Loricae and Oxygen Defect Co‐Promoted Superior Activities and Excellent Durability of RuO ₂ Nanoparticles Towards the pH‐Universal H ₂ Evolution

Abstract This work reports a strategy that integrates the carbon nanotube (CNT) supporting, ultrathin carbon coating and oxygen defect generation to fabricate the RuO ₂ based catalysts toward the pH‐universal hydrogen evolution reaction (HER) with high efficiencies. Specifically, the CNT supported RuO ₂ nanoparticles with ultrathin carbon loricae and rich oxygen vacancies at the surface (C@OV‐RuO ₂ /CNTs‐325) have been synthesized. The C@OV‐RuO ₂ /CNTs‐325 shows superior activities and excellent durability for the HER. It only requires overpotentials of 36.1, 18.0, and 19.3 mV to deliver −10 mA cm ⁻² in the acidic, neutral, and alkaline media, respectively. Its HER activities are comparable to that of the Pt/C in the acidic media but higher than those of the Pt/C in the neutral and alkaline media. The C@OV‐RuO ₂ /CNTs‐325 shows excellent HER durability with no activity losses for > 500 h in the acidic, neutral or alkaline media at −250 mA cm ⁻² . The density‐functional‐theory calculations indicate that the CNT supporting, the carbon coating, and the OVs can modulate the d‐band centers of Ru, increasing the HER activities of C@OV‐RuO ₂ /CNTs‐325, and stabilize the Ru atoms in the catalyst, increasing the durability of the C@OV‐RuO ₂ /CNTs‐325. More interestingly, the C@OV‐RuO ₂ /CNTs‐325 shows great potential for practical applications toward overall seawater splitting.