A Facile Approach for Pt Single Atoms Deposition on Two-Dimensional Calcium Niobate Nanosheets for Photocatalytic Hydrogen Evolution

Abstract

Single atoms (SAs) have drawn significant attention, because of their enormous catalytic activity and high atom-utilization efficiency. Particularly, for H 2 evolution, SAs decorated on two-dimensional (2D) nanosheets have great potential, because of the distinctive advantages offered by 2D materials, such as abundant surfaceactive sites, high specific surface area, and better-photoexcited charge carrier separation. Despite the significant advantages of 2D materials as support, the deposition of SAs on 2D nanosheets is still a great challenge and rarely has been reported. This work reports the facile deposition of Pt-SAs and Pt-SAs/nanoclusters (NCs) on Ca 2 Nb 3 O 10 and Ndoped Ca 2 Nb 3 O 10−x N x nanosheets, respectively, via a modified photodeposition method. We observe that the presence of a suitable concentration of tetrabutylammonium (TBA + ) ions is essential for the successful deposition of Pt-SAs and Pt-SAs/NC via Pt−O bond formation on Ca 2 Nb 3 O 10 and Ca 2 Nb 3 O 10−x N x nanosheets, respectively. The findings of aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC HAADF-STEM) validated the successful deposition of Pt-SAs on Ca 2 Nb 3 O 10 and Pt-SAs/NC on N-doped Ca 2 Nb 3 O 10−x N x nanosheets, which are further validated via X-ray absorption fine structure (XAFS) spectroscopy. As a result, Ca 2 Nb 3 O 10 -Pt SA exhibited excellent H 2 production: 280.5 μmol h −1 , which is 2.7 and 6.1 times higher, compared to Ca 2 Nb 3 O 10 -Pt NP (105.08 μmol h −1 ) and bare Ca 2 Nb 3 O 10 (46.05 μmol h −1 ). Furthermore, N-doped Ca 2 Nb 3 O 10−x N x -Pt SA/NC demonstrated 2.0 and 3.6 times superior H 2 evolution, in contrast to Ca 2 Nb 3 O 10−x N x -Pt NP under full-spectrum and visible light irradiation (λ > 420 nm), respectively. Consequently, this work provides a new direction for SAs deposition on exfoliated perovskite nanosheets in the presence of TBA + ions used during exfoliation, offering a potential strategy that can be applied to a large library of nanosheets synthesized via softchemical exfoliation.

BiFeO3-Based All Perovskite Oxides Direct Z-Scheme Heterostructure for Efficient Oxygen Evolution

“…The XRD pattern of flocculated CNO nanosheets is in agreement with previous literature. 26,32 The XRD pattern of the BFO-Co/CNO sample mainly shows diffraction peaks of BFO due to its higher contents, and the attenuated peak of CNO in the composite is attributable to its presence and excellent dispersion. The successful synthesis of BFO was also confirmed via FTIR (Figure 1d) spectra where two fundamental bands at ∼441 and ∼548 cm −1 were observed that are characteristics of Fe−O stretching and bending Nb−OH and Nb�O present on the surface of the nanosheets, respectively.…”

“…KCa 2 Nb 3 O 10 layered material was prepared using K 2 CO 3 , CaCO 3 , and Nb 2 O 5 in K/Ca/Nb = 1.05/2/3 molar ratio according to the previous report . The mixture was calcined for 12 h at 1200 °C at a 10 °C/min rate.…”

“…KCa 2 Nb 3 O 10 layered material was prepared using K 2 CO 3 , CaCO 3 , and Nb 2 O 5 in K/Ca/ Nb = 1.05/2/3 molar ratio according to the previous report. 26 The mixture was calcined for 12 h at 1200 °C at a 10 °C/min rate. The asobtained KCa 2 Nb 3 O 10 sample was treated with 5 M HNO 3 solution for 72 h. The acid was changed with fresh stock after every 24 h. The acid-treated sample was washed well with deionized water and dried in air overnight.…”

Highly selective photocatalytic oxidation of 5-hydroxymethylfurfural by interfacial Pt–O bonding Pt–Ov–BiOBr

“…23 Furthermore, by creating bonds as a conductive layer through the unsaturated coordination atoms close to the Ov, they can also quicken the interfacial charge transfer. [24][25][26] As a result, the addition of Ov allows for the quick migration of photogenerated electrons from the semiconductor body to the noble metal in order to reduce oxygen and produce O 2…”

“…23 Furthermore, by creating bonds as a conductive layer through the unsaturated coordination atoms close to the Ov, they can also quicken the interfacial charge transfer. 24–26 As a result, the addition of Ov allows for the quick migration of photogenerated electrons from the semiconductor body to the noble metal in order to reduce oxygen and produce ˙O 2 − , while also enriching the photogenerated vacancies at the catalyst's interface in contact with the noble metal. 27 This stimulates the formation of ˙O 2 − to interact more quickly with the intermediates formed during the oxidation of HMF to produce DFF.…”