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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.

To design safe and electrochemically stable electrolytes for lithium-ion batteries, this study describes the synthesis and the utilization of new deep eutectic solvents (DESs) based on the mixture of 2,2,2-trifluoroacetamide (TFA) with a lithium salt (LiTFSI, lithium bis[(trifluoromethane)sulfonyl]imide). These prepared DESs were characterized in terms of thermal properties, ionic conductivity, viscosity, and electrochemical properties. Based on the appearance of the product and DSC measurements, it appears that this system is liquid at room temperature for LiTFSI mole fraction ranging from 0.25 to 0.5. At χ LiTFSI = 0.25, DESs exhibited favorable electrolyte properties, such as thermal stability (up to 148 °C), relatively low viscosity (42.2 mPa.s at 30 °C), high ionic conductivity (1.5 mS.cm –1 at 30 °C), and quite large electrochemical stability window up to 4.9–5.3 V. With these interesting properties, selected DES was diluted with slight amount of ethylene carbonate (EC). Different amounts of EC ( x = 0–30 %wt) were used to form hybrid electrolytes for battery testing with high voltage LiMn 2 O 4 cathode and Li anode. The addition of the EC solvent into DES expectedly aims at enhancing the battery cycling performance at room temperature due to reducing the viscosity. Preliminary results tests clearly show that LiTFSI-based DES can be successfully introduced as an electrolyte in the lithium-ion batteries cell with a LiMn 2 O 4 cathode material. Among all of the studied electrolytes, DES (LiTFSI: TFA = 4:1 + 10 %wt EC) is the most promising. The EC-based system exhibited a good specific capacity of 102 mAh.g –1 at C/10 with the theoretical capacity of 148 mAh.g –1 and a good cycling behavior maintaining at 84% after 50 cycles.