Ion-Sieve-Confined Synthesis of Size-Tunable Ru for Electrochemical Hydrogen Evolution.

The controllable and low-cost synthesis of nanometal particles is highly desired in scientific and industrial research. Herein, size-tunable Ru nanoparticles were synthesized by using a novel ion-sieve-confined reduction method. The H 2 TiO 3 ion-sieve was used to adsorb Ru 3+ into the hydroxyl-enriched porous [TiO 3 ] 2- layers. The confined environment of the interlayer space facilitates Ru-Ru collision and bonding during annealing, achieving a precise reduction from Ru 3+ to Ru 0 without additional reductants. Owing to the confinement effect, Ru 0 nanoparticles are uniformly embedded in the pores on the surface of the postannealed TiO 2 matrix (Ru@TiO 2 ). Ru@TiO 2 exhibited a lower overpotential than Pt/C (57 vs 87 mV at 10 mA cm -2 ) for the HER in 0.1 M KOH solution. The confinement-induced reduction of metal ions was also preliminarily proved in ion-exchanged zeolites, which provides facile and abundant approaches for the size-controllable synthesis of nanometal catalysts with high catalytic activity.