Ultrathin Lanthanum Tantalate Perovskite Nanosheets Modified by Nitrogen Doping for Efficient Photocatalytic Water Splitting.

Lv, Meilin; Sun, Xiaoqin; Wei, Shunhang; Shen, Cai; Mi, Yongli; Xu, Xiaoxiang · ACS Nano · 2017

basic_science · Level V

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Abstract

Ultrathin nitrogen-doped perovskite nanosheets LaTa<sub>2</sub>O<sub>6.77</sub>N<sub>0.15</sub><sup>-</sup> have been fabricated by exfoliating Dion-Jacobson-type layered perovskite RbLaTa<sub>2</sub>O<sub>6.77</sub>N<sub>0.15</sub>. These nanosheets demonstrate superior photocatalytic activities for water splitting into hydrogen and oxygen and remain active with photon wavelengths as far as 600 nm. Their apparent quantum efficiency under visible-light illumination (λ ≥ 420 nm) approaches 1.29% and 3.27% for photocatalytic hydrogen and oxygen production, being almost 4-fold and 8-fold higher than bulk RbLaTa<sub>2</sub>O<sub>6.77</sub>N<sub>0.15</sub>. Their outstanding performance likely stems from their tiny thickness (single perovskite slab) that essentially removes bulk charge diffusion steps and extends the lifetime of photogenerated charges. Theoretical calculations reveal a peculiar 2D charge transportation phenomenon in RbLaTa<sub>2</sub>O<sub>6.77</sub>N<sub>0.15</sub>; thus, exfoliating RbLaTa<sub>2</sub>O<sub>6.77</sub>N<sub>0.15</sub> into LaTa<sub>2</sub>O<sub>6.77</sub>N<sub>0.15</sub><sup>-</sup> nanosheets has limited impact on charge transportation properties but significantly enhances the surface areas which contributes to more reaction sites.