Confining ultrafine Ru clusters into TiO2 lattice frameworks to yield efficient and ultrastable electrocatalysts towards practical hydrogen evolution

Ru-based nanomaterials are among the best electrocatalysts for hydrogen evolution reaction (HER) in alkaline media, however their stability is still questionable, especially under harsh conditions towards practical applications (i.e., 80 °C, 6 M KOH). We demonstrate that the conventionally surface-supported Ru electrocatalysts are actually not stable under harsh conditions due to the weak interaction between Ru and supports, although they are stable under mild conditions. Here, we report a lattice-confined approach to concurrently enhance the stability and intrinsic activity of Ru via confining ultrafine Ru clusters into TiO2 lattice frameworks. Impressively, such confined Ru delivers outstanding performance for HER under harsh conditions, such as a small overpotenital of 116 mV at 800 mA cm−2, and long-time stability for 200-h continuous HER at 300 mA cm−2. As uncovered by both computational and experimental results, the lattice-confined strategy can significantly enhance the interaction between Ru and TiO2 for promoting the electron transfer from Ru to TiO2, thereby strongly stabilizing Ru for avoiding the dissociation and aggregation of Ru during the stability test. Therefore, the lattice-confined strategy may stand out as a robust approach for boosting the activity and stability of electrocatalysts.