Abstract
•Sol-gel preparation of mesoporous TeO2 decorated with Ag/Ag2O heterojunction.•Bandgap, light absorption, and charge separation improved by Ag/Ag2O.•High H2 yield of 288.9 µmolg−1h−1 by 1.5% Ag/Ag2O-TeO2, >13-fold to pure TeO2.•Applicable photocatalyst for H2 production with reusability for five cycles.
Ceramic oxide photocatalysts have become significant materials for green energy production. This work presents the formation of various silver/silver oxide (Ag/Ag2O)-supported sol-gel synthesized tellurium dioxide (TeO2) nanojunction networks. The produced heterojunction photocatalysts were considered by different tools and demonstrated a photoactivity enhancement by introducing Ag/Ag2O at lower amounts (0.5–2.0 wt. %) without changing the surface texture or crystalline structure of TeO2. The decoration and existence of Ag/Ag2O were confirmed by high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The 1.5 wt. % Ag/Ag2O-TeO2 demonstrated a broader visible-light response edged at 571 nm with a minimum bandgap energy of 2.18 eV compared to pristine TeO2 (543 nm and 2.38 eV, respectively). In addition, the formed heterojunctions were tested for hydrogen (H2) production from water in the presence of 10% glycerol and hexchloroplatinic acid as hole scavenger and cocatalyst, respectively. The 1.5 wt. % Ag/Ag2O-TeO2 demonstrated a promoted H2 production of 288.9 µmol g−1h−1, which is > 13-fold higher than the pristine TeO2 with admirable stability for five cycles. This improved H2 production using the novel Ag/Ag2O-TeO2 heterojunction is explained by the efficient light-harvesting, effective separation of the photogenerated charges within the nanojunction interface, and the synergistic effects of Ag existence and Pt deposition.