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

Abstract

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.

Application of Exfoliated Inorganic Nanosheets for Strongly‐Coupled Hybrid Photocatalysts

“…For the efficient exfoliation of layered inorganic solids, the interlayer distance of the pristine material should be gradually expanded by exchanging small interlayer ions with larger ones, thus reducing the chemical interaction between the host layers . Several layered materials, including layered transition metal oxides (TMOs), layered double hydroxides (LDHs), aluminosilicate clays, layered metal chalcogenides (TMDs), and carbon‐based nanosheets are suitable as host compounds for the intercalation‐based exfoliation method (Figure c) …”

“…The interlayer space of the protonated phase can be further expanded by replacing the protons with specific bulky organic cations, such as tetrabutylammonium (TBA + ). Owing to the weakened interlayer interactions of the host lattice, it can be exfoliated into individual nanosheets with gentle shaking or ultrasonic treatment . Finally, the resulting oxide nanosheets are obtained as a colloidal suspension.…”

“…Since the exfoliated inorganic nanosheets have high diversity and tunability of chemical compositions and crystal, band, and surface structures, the photocatalytic performance of 2D nanosheet‐based hybrid materials can be easily optimized. Recently, several investigations report the synthesis of efficient hybrid photocatalysts by employing 2D nanosheets as building blocks for hybridization with other semiconductor nanostructures …”

Ammonolysis‐Driven Exsolution of Ru Nanoparticle Embedded in Conductive Metal Nitride Matrix to Boost Electrocatalyst Activity

“…Ru K‐edge EXAFS analysis revealed that the ammonolysis was accompanied by local structural transition. As can be observed from Figure 2b, RTO20 exhibits typical Fourier transform (FT) features exhibited by a layered trititanate phase, [ 30 ] clarifying the substitution of Ru ions into the Ti sites of the trititanate lattice. Conversely, RTN20 exhibits an intense FT peak at ≈2.4 Å, which is ascribed to the Ru─Ru bonding pair, as observed in the Ru metal reference.…”