Issue 12, 2023

Defect engineering of two-dimensional Nb-based oxynitrides for visible-light-driven water splitting to produce H2 and O2

Abstract

Two-dimensional (2D) Nb-based oxynitrides are promising visible-light-responsive photocatalysts for the water splitting reaction, but their photocatalytic activity is degraded by the formation of reduced Nb5+ species and O2− vacancies. To understand the influence of nitridation on the formation of crystal defects, this study synthesized a series of Nb-based oxynitrides through the nitridation of LaKNaNb1−xTaxO5 (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0). During nitridation, K and Na species volatilized, which helped transform the exterior of LaKNaNb1−xTaxO5 into a lattice-matched oxynitride shell. Ta inhibited defect formation, yielding Nb-based oxynitrides with a tunable bandgap between 1.77 and 2.12 eV, straddling the H2 and O2 evolution potentials. After loading with Rh and CoOx cocatalysts, these oxynitrides exhibited good photocatalytic activity for H2 and O2 evolution in visible light (650–750 nm). The nitrided LaKNaTaO5 and LaKNaNb0.8Ta0.2O5 delivered the maximum H2 (19.37 μmol h−1) and O2 (22.81 μmol h−1) evolution rates, respectively. This work provides a strategy for preparing oxynitrides with low defect densities and demonstrates the promising performance of Nb-based oxynitrides for water splitting.

Graphical abstract: Defect engineering of two-dimensional Nb-based oxynitrides for visible-light-driven water splitting to produce H2 and O2

Supplementary files

Article information

Article type
Paper
Submitted
15 Dec. 2022
Accepted
06 Apr. 2023
First published
06 Apr. 2023
This article is Open Access
Creative Commons BY-NC license

Nanoscale Adv., 2023,5, 3260-3266

Defect engineering of two-dimensional Nb-based oxynitrides for visible-light-driven water splitting to produce H2 and O2

C. Xu, Y. Wang, Q. Guo and X. Wang, Nanoscale Adv., 2023, 5, 3260 DOI: 10.1039/D2NA00915C

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