Ar/H2/O2-Controlled Growth Thermodynamics and Kinetics to Create Zero-, One-, and Two-Dimensional Ruthenium Nanocrystals towards Acidic Overall Water Splitting

A gas controlled formation strategy is developed to synthesize free-standing 0D Ru nanoparticles, 1D Ru nanowires, and 2D Ru nanosheets through in-situ regulated growth thermodynamics and kinetics with typical inert, reductive, and oxidative gases (Ar/H-2/O-2). The growth process of these Ru nanoparticles, nanowires, and nanosheets follow non-directional growth, shape-directed nanoparticle attachment, and directional growth mechanisms, respectively. Kinetics studies approve that H-2 accelerates the reduction rate of the Ru precursor, while O-2 depresses the reduction. The calculation results of the Gibbs surface free energy under different gas coverage further show that small molecules' gas can effectively regulate the surface state and growth rate. These Ru nanocrystals exhibit excellent acidic water splitting performance. This work has systematically studied the influence of the small molecule gas on the formation process of the Ru nanocrystals, and provides an effective idea for the development and research of high-performance nanomaterials in the future.