Affiliation:
1. Centre for Nano and Material Sciences Jain (Deemed‐to‐be University) Jain Global Campus, Kanakapura Bangalore Karnataka 562112 India
2. Department of Chemical Engineering Laval University 1065 Avenue de la Médecine Québec QC G1V0A6 Canada
3. Nanocatalysis and Solar Fuels Research Laboratory Department of Materials Science & Nanotechnology Yogi Vemana University Kadapa Andhra Pradesh 516005 India
Abstract
The present study investigates the phase formation of the titanium oxynitride (TiOxNy) system using the “oxide‐to‐oxynitride” and “nitride‐to‐oxynitride” synthesis strategies. The XRD patterns of both the materials show peaks corresponding to Ti–N and Ti–O lattices, confirming the formation of Ti–oxynitride system. Accordingly, the presence of Ti3+–N3− and Ti4+–2O2− signals is also confirmed by XPS analysis. The TiOxNy derived from oxide (TO‐TON) exhibits wide visible light absorption with a narrow‐bandgap energy of ≈2.30 eV, while the nitride‐derived–TiOxNy (TN‐TON) exhibits relatively a wide‐bandgap energy (≈2.92 eV) along with the plasmonic band of TiN. In line with this, an enhanced recombination resistance and charge carriers with extended lifetime are observed for TN‐TON (4.47 ns) and TO‐TON (4.33 ns) systems via photoluminescence and time‐resolved photoluminescence analysis. Consequently, the TN‐TON system demonstrates a superior H2/NH3 production at a rate of ≈1432/646 μmol g−1 h−1 under solar irradiation, while it is ≈1136/553 μmol g−1 h−1 for the TO‐TON system. These efficiencies are ≈20× and 3× times higher than the bare TiN and TiO2, respectively, toward H2/NH3 production. The insights from this study demonstrate that the nitride‐ and oxide‐based precursors likely manifest synergistic and competitive properties, respectively, in the resulting oxynitride system.