LAUSR

Small gas molecule such as H2 has been widely reported to be used as the structure-directing agent (SDA) that assists synthetic processes of diverse structured metal nanocrystals. Herein, we systematically investigated the H2-mediated growth mechanisms of branched Ni (Ni-BN) using a combined experimental and theoretical approach (molecular dynamics). Two types of kinetic models describing Ni precursor reduction and Ni nuclei overgrowth forming branched Ni-BN have been established, which quantitatively illustrate kinetic roles of H2 played during Ni-BN synthesis. On one hand, the H2 significantly promoted Ni precursor reduction rate with the value being of about two times higher than that without H2; on the other hand, the dissociatively adsorbed atomic H on Ni nuclei greatly affected the deposition kinetics (deposition rate and deposition equilibrium) of the reduced Ni atoms. Synergistically, the faster Ni precursor reduction rate associated with enhanced Ni atom deposition kinetics resulted in the overgr...