Scalable synthesis of ultra-small Ru2P@Ru/CNT for efficient seawater splitting

In this study, an ultra-fast and simple solvent-free microwave method was successfully demonstrated using a series of ultra-small (~2.5 nm) surfactant-free Ru2[email protected]/CNT heterostructures for the first time. The structure has a high-density Ru component and Ru2P component interface, which accelerates the hydrogen evolution reaction (HER). The prepared Ru2[email protected]/CNT demonstrated excellent catalytic effects for the HER in alkaline media and real seawater. The experimental results indicate that ratio-optimized Ru2[email protected]/CNT (Ru2P:Ru = 66:34) requires only 23 and 29 mV to reach 10 mA cm–2 in 1.0 mol/L KOH and real seawater, respectively. These values are 10 and 24 mV lower than those of commercial Pt/C in 1.0 mol/L KOH (33 mV) and real seawater (53 mV), respectively, making it among the best non-Pt HER reported in the literature. Additionally, the TOF of Ru2[email protected]/CNT in alkaline freshwater and seawater were 13.1 and 8.5 s–1, respectively. These exceed the corresponding values for Pt/C, indicating that the catalyst has excellent intrinsic activity. The high current activity of Ru2[email protected]/CNT in 1.0 mol/L KOH was explored, and only 77 and 104 mV were required to reach 500 and 1000 mA cm–2, respectively. After 100 h of durability testing, the catalyst retained excellent catalytic and structural stability in low current density, high current density, and seawater.