Carbon Nanotube Support, Carbon Loricae and Oxygen Defect Co-Promoted Superior Activities and Excellent Durability of RuO₂ Nanoparticles Towards the pH-Universal H₂ Evolution

This work reports a strategy that integrates the carbon nanotube (CNT) supporting, ultrathin carbon coating and oxygen defect generation to fabricate the RuO₂ based catalysts toward the pH-universal hydrogen evolution reaction (HER) with high efficiencies. Specifically, the CNT supported RuO₂ nanoparticles with ultrathin carbon loricae and rich oxygen vacancies at the surface (C@OV-RuO₂/CNTs-325) have been synthesized. The C@OV-RuO₂/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-RuO₂/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-RuO₂/CNTs-325, and stabilize the Ru atoms in the catalyst, increasing the durability of the C@OV-RuO₂/CNTs-325. More interestingly, the C@OV-RuO₂/CNTs-325 shows great potential for practical applications toward overall seawater splitting.