Electrocatalytic hydrogen evolution performance of RuO2 nanorods grown on top of WO3 nanotube arrays

Water electrolysis has been deemed as a simple, safe, and clean way to realize sustainable hydrogen production. However, efficacious water electrolysis for hydrogen production is highly dependent on efficient and stable electrocatalysts. Traditional powder catalysts have defects such as severe particle aggregation, poor conductivity, and weak substrate adhesion. Self-supporting electrodes grown in situ on conductive substrates as electrocatalysts could avoid these problems and therefore exhibit high catalytic activity and stability. Herein, one-dimensional RuO₂ nanorods (NRs) were grown on top of WO₃ nanotube arrays (NTA) through a facile solution impregnation method followed by a high-temperature calcination. The obtained self-supported RuO₂ NRs/WO₃ NTA electrode demonstrates a superb electrocatalytic activity toward hydrogen evolution reaction (HER) in both basic and acidic media. To achieve a current density of 10 mA cm⁻², the required overpotentials are 33 mV in 1 M KOH and 62 mV in 0.5 M H₂SO₄, respectively. Furthermore, RuO₂ NRs/WO₃ NTA also shows excellent long-term electrochemical stability for continuous hydrogen generation over 50 h in both basic and acidic electrolytes. The superb HER activity of RuO₂ NRs/WO₃ NTA could be attributed to the structural merits including large surface area of RuO₂ with abundant catalytically active sites, specific charge transport channel ensuring enhanced reaction kinetics, and abundant open space between RuO₂ nanorods favorable for fast mass transfer and electrolyte accessibility. The present work sheds new light on designing novel one-dimensional composite structures as highly efficient electrocatalyst for sustainable hydrogen generation. Simultaneously, the designed nanorod/nanotube array composite structure in this work is also expected to be applied in other energy conversion devices.