This work demonstrates a two-step gram-scale synthesis of presynthesized silver (Ag) nanoparticles impregnated with mesoporous TiO 2 and evaluates their feasibility for wastewater treatment and hydrogen gas generation under natural sunlight. Paracetamol was chosen as the model pharmaceutical pollutant for evaluating photocatalytic performance. A systematic material analysis (morphology, chemical environment, optical bandgap energy) of the Ag/TiO 2 photocatalyst powder was carried out, and the influence of material properties on the performance is discussed in detail. The experimental results showed that the decoration of anatase TiO 2 nanoparticles (size between 80 and 100 nm) with 5 nm Ag nanoparticles (1 wt %) induced visible-light absorption and enhanced charge carrier separation. As a result, 0.01 g/L Ag/TiO 2 effectively removed 99% of 0.01 g/L paracetamol in 120 min and exhibited 60% higher photocatalytic removal than pristine TiO 2 . Alongside paracetamol degradation, Ag/TiO 2 led to the generation of 1729 μmol H 2 g −1 h −1 . This proof-of-concept approach for tandem pollutant degradation and hydrogen generation was further evaluated with rare earth metal (lanthanum)-and nonmetal (nitrogen)-doped TiO 2 , which also showed a positive response. Using a combination of ab initio calculations and our new theory model, we revealed that the enhanced photocatalytic performance of Ag/TiO 2 was due to the surface Fermi-level change of TiO 2 and lowered surface reaction energy barrier for water pollutant oxidation. This work opens new opportunities for exploiting tandem photocatalytic routes beyond water splitting and understanding the simultaneous reactions in metal-doped metal oxide photocatalyst systems under natural sunlight.

Mesoporous CeO 2 was synthesized by the nanocasting pathway using the mesoporous SBA-15 silica as structure template and cerium nitrate as the CeO 2 precursor via a solid-liquid route. Ag/CeO 2 catalysts were prepared by three di®erent methods: wetness impregnation (WI), deposition-precipitation with urea (DPU) and impregnation-reduction with citrate (IRC), with a loading of silver of 4 wt.%. They were characterized by elemental analysis, H 2 -TPR, X-ray powder di®raction (XRD), Brunauer, Emmett and Teller (BET) surface area, di®use re°ectance and ultraviolet visible spectroscopy (DR/UV-Vis). Ag/CeO 2 catalysts retain the physical properties of mesoporous ceria and its hexagonal order. Catalytic oxidation of propylene and catalytic reduction of NO with propylene as a reducing agent were investigated on Ag/mesoporous ceria catalysts. The silver/mesoporous ceria system toward the deep oxidation of propylene and the catalytic reduction of NO depends on the catalyst preparation method. Ag/CeO 2 (IRC) can be ascribed to higher surface lattice oxygen mobility over this catalyst and also to the strong interaction between silver and mesoporous ceria.

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