Preparation of niobium based oxynitride nanosheets by exfoliation of Ruddlesden-Popper phase precursor

Abstract

To cite this version:Rietveld refinement of X-ray powder diffraction data in space group P4/mmm and considering a two-phase mixture, due to the difference in the degree of hydration, with a = 3.894(2) Å and c = 17.90(8) Å for the most hydrated phase and a = 3.927(6) and c = 17.09 (2) for the less one. Optical band gaps were measured by diffuse reflectance UV-Vis indicating a red shift of Eg to the visible region. The oxynitride layered perovskite was then protonated and exfoliated into nanosheets. TEM images and SAED patterns of the nanosheets proved that exfoliation was successful, showing lattice parameters quite compatible with the Rietveld refinement.

Control of the Photocatalytic Activity of Metastable Layered Oxynitride K2LaTa2O6N through Topochemical Transformation of Tuned Oxide Precursors

“…Mallouk et al first showed that the Dion–Jacobson (D–J) phase oxides RbLaNb 2 O 7 and RbCa 2 Nb 3 O 10 could be transformed topochemically into Ruddlesden–Popper (R–P) phase oxynitrides Rb 1+ x LaNb 2 O 7– x N x · y H 2 O and Rb 1+ x Ca 2 NB 3 O 10– x N x · y H 2 O by nitridation of the oxide precursors with the aid of alkaline metal carbonates . Similar D–J to R–P topochemical conversions have been reported using KCa 2 Nb 3 O 10 and RbNdNb 2 O 7 , which were converted into K 1+ x Ca 2 Nb 3 O 10– x N x and Rb 2 NdNb 2 O 6 N, respectively. Recently, this topochemical method has been applied to the synthesis of Ta 5+ -based layered oxynitrides. , For example, K 2 LaTa 2 O 6 N·1.6H 2 O is an R–P phase layered oxynitride that functions as a visible-light-driven photocatalyst for H 2 evolution .…”

Theoretical-experimental evaluation of the photocatalytic activity of KCa2Ta3−xNbxO10

“…There are two distinct crystallographic positions for the transition metals, two equivalent octahedra (Oct1) constituting the slab edges while the other one [2]. No significant morphological changes were observed for the synthesized materials, as evidenced by SEM results (SD-03) and large surfaces assigned to (0 1 0) planes were observed [13]. Stoichiometry of the samples was confirmed by SEM-EDXS (Table 1).…”

Synthesis of Three-Layer Perovskite Oxynitride K2Ca2Ta3O9N·2H2O and Photocatalytic Activity for H2 Evolution under Visible Light

“…Mallouk et al have reported that thermal ammonolysis of Dion–Jacobson oxides (e.g., RbCa 2 Nb 3 O 10 and RbLaNb 2 O 7 ) in the presence of Rb 2 CO 3 resulted in the formation of Ruddlesden–Popper phases of Rb 1+ x Ca 2 Nb 3 O 10– x N x · y H 2 O and Rb 1+ x LaNb 2 O 7– x N x · y H 2 O . Follow-up studies have shown that a similar topochemical conversion was possible for KCa 2 Nb 3 O 10 and RbNdNb 2 O 7 to yield K 1+ x Ca 2 Nb 3 O 10– x N x and Rb 2 NdNb 2 O 6 N, respectively. We have recently confirmed the adoptability of this topochemical approach to synthesize a new layered oxynitride, K 2 LaTa 2 O 6 N·1.6H 2 O, which consists of double-layer perovskite slabs interleaved with K + ions and hydrated water molecules .…”