Ag/Ag2O-decorated sol-gel-processed TeO2 nanojunctions for enhanced H2 production under visible light.

• Sol-gel preparation of mesoporous TeO 2 decorated with Ag/Ag 2 O heterojunction. • Bandgap, light absorption, and charge separation improved by Ag/Ag 2 O. • High H 2 yield of 288.9 µmolg−1h−1 by 1.5% Ag/Ag 2 O-TeO 2 , >13-fold to pure TeO 2. • Applicable photocatalyst for H 2 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/Ag 2 O)-supported sol-gel synthesized tellurium dioxide (TeO 2) nanojunction networks. The produced heterojunction photocatalysts were considered by different tools and demonstrated a photoactivity enhancement by introducing Ag/Ag 2 O at lower amounts (0.5–2.0 wt. %) without changing the surface texture or crystalline structure of TeO 2. The decoration and existence of Ag/Ag 2 O were confirmed by high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The 1.5 wt. % Ag/Ag 2 O-TeO 2 demonstrated a broader visible-light response edged at 571 nm with a minimum bandgap energy of 2.18 eV compared to pristine TeO 2 (543 nm and 2.38 eV, respectively). In addition, the formed heterojunctions were tested for hydrogen (H 2) production from water in the presence of 10% glycerol and hexchloroplatinic acid as hole scavenger and cocatalyst, respectively. The 1.5 wt. % Ag/Ag 2 O-TeO 2 demonstrated a promoted H 2 production of 288.9 µmol g−1h−1, which is > 13-fold higher than the pristine TeO 2 with admirable stability for five cycles. This improved H 2 production using the novel Ag/Ag 2 O-TeO 2 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. [ABSTRACT FROM AUTHOR]