Designing an efficient hybrid structure photocatalyst for photocatalytic decomposition and hydrogen (H2) evolution has been considered a great choice to develop renewable technologies for clean energy production and environmental remediation. Enhanced charge transfer (CT) based on the interaction between a noble metal and a semiconductor is a crucial factor influencing the movement of photogenerated electron–hole pairs. Herein, we focus on the recent advances related to plasmon-enhanced noble metals and the semiconductor nature to drive the photocatalytic H2 production and photodegradation of the organic dye rhodamine B (RhB) under UV and visible light irradiation. Specifically, the combination of concerted catalysis and green nanoengineering strategies to design ZnO-based composite photocatalysts and their decoration with metallic Ag have been realized by the radio frequency (RF) sputtering technique at room temperature. This simultaneity enhances the interface coupling between Ag and ZnO and reduces the energy threshold. The creation of charge transfer in the heterojunction and Schottky barrier changes the photoelectronic properties of the as-synthesized Al-doped ZnO (AZO); afterward, these effects promote the migration, transportation, and separation of photoinduced charge carriers and enhance the light-harvesting efficiency. As a result, the as-synthesized AZO-20 hybrid nanostructure exhibits a photocurrent density of 2.5 mA/cm2 vs Ag/AgCl, which is improved by almost 12 times compared with that of bare ZnO (0.2 mA/cm2). The hydrogen evolution rates of AZO-20 were ∼38 and ∼24 μmol/h under UV and visible light exposure, which are almost five- and tenfold higher than those of pristine ZnO, respectively. Additionally, the RhB degradation efficacies of the obtained AZO-20 were greater than almost 97 and 82% under UV and visible light illumination, respectively. The achieved apparent rate constant for the photocatalytic RhB decomposition was 0.014 min–1, indicating that it is 14-fold than that in pristine ZnO (0.001 min–1). Heterostructure AZO photocatalysts possess excellent practical stability in the water-splitting reaction and photocatalytic RhB decomposition, posing as promising candidates in practical works for pollution and energy challenges.

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This work focuses on the formation of Ir3+ dopants in the host TiO2 matrix to decrease the band gap energy and a built-in electric field at the interface between Ir0 and TiO2. X-ray diffraction results show that the anatase percentage is increased from 70 to 90% with increasing Ir doping concentration using the hydrothermal procedures at 200 °C for 24 h. X-ray photoelectron spectroscopy results demonstrate that the binding energies of Ti4+ (Ti 2p1/2 and Ti 2p3/2) shift slightly positively after Ir doping. The influence of Ir doping on the photoelectrochemical and optical properties of anatase/rutile TiO2 is characterized by linear sweep voltammetry and photoluminescence spectroscopy. These results suggest that the photoinduced electron–hole pair recombination rate is decreased in the presence of the Ir dopant. Outstanding H2 evolution reaction efficiencies of 48 and 23.5 μmol·h–1·g–1 with apparent quantum efficiency values of approximately 15.7 and 4.5% determined at 365 and 420 nm, respectively, are achieved with the 1.0% Ir/TiO2 specimen in photocatalytic systems to enhance hydrogen evolution.