Exfoliated Metal Oxide Nanosheets as Effective and Applicable Substrates for Atomically Dispersed Metal Nanoparticles with Tailorable Functionalities

An effective methodology to stabilize highly dispersed metal nanoparticles is developed by employing the exfoliated 2D metal oxide nanosheets with variable surface structures as substrates. The selection of appropriate crystal structure of titanate nanosheet is very crucial in stabilizing atomically dispersed Pt nanoparticles through the tuning of chemical interaction between Pt and titanate substrate. A theoretical study using density functional theory calculations confirms the significant influence of the crystal structure of layered titanate nanosheet on the crystal growth behavior of immobilized metal nanoparticle. As a consequence of the good dispersion of Pt nanoparticles, the Pt–trititanate nanohybrids with stronger interaction show much higher content of atomically dispersed Pt and better catalyst performances than do the Pt–lepidocrocite titanate ones. The applicability of the present method for other metal species is evidenced by the successful tuning of the crystal size and functionality of Au nanoparticles via immobilization on layered titanate nanosheets. The functionality of Au for surface-enhanced Raman spectroscopy becomes improved by the anchoring on the lepidocrocite-type titanate nanosheet. The present study underscores that the use of the metal oxide 2D nanosheets with appropriate surface structure as substrates is effective in tailoring the crystal growth and the functionalities of immobilized metal nanoparticles.