The removal of pharmaceuticals from wastewater is critical due to their considerable risk on ecosystems and human health. Additionally, they are resistant to conventional chemical and biological remediation methods. Two-dimensional nanomaterials are a promising approach to face this challenge due to their combination of high surface areas, high electrical conductivities, and partially optical transparency. This review discusses the state-of-the-art concerning their use as adsorbents, oxidation catalysts or photocatalysts, and electrochemical catalysts for water treatment purposes. The bibliographic search bases upon academic databases including articles published until August 2021. Regarding adsorption, high removal capacities (>200 mg g−1) and short equilibrium times (<30 min) are reported for molybdenum disulfide, metal-organic frameworks, MXenes, and graphene oxide/magnetite nanocomposites, attributed to a strong adsorbate-adsorbent chemical interaction. Concerning photocatalysis, MXenes and carbon nitride heterostructures show enhanced charge carriers separation, favoring the generation of reactive oxygen species to degrade most pharmaceuticals. Peroxymonosulfate activation via pure or photo-assisted catalytic oxidation is promising to completely degrade many compounds in less than 30 min. Future work should be focused on the exploration of greener synthesis methods, regeneration, and recycling at the end-of-life of two-dimensional materials towards their successful large-scale production and application.

Yttrium-doped copper tungstate photoelectrodes are prepared by depositing an yttrium-doped CuWO4 film (Y-CuWO4) on conductive glass substrates by dip coating. The morphology and chemical composition confirm the fabrication of yttrium-doped CuWO4 films. The optical bandgap of the photoelectrodes is studied by UV-Vis diffuse reflectance and a bandgap of 2.30 eV is obtained for the pure CuWO4 photoelectrode. The yttrium-doped photoelectrodes show a small shift of the bandgap to higher values, which according to DFT calculations can be ascribed to a higher density of electronic states in the first conduction band from incorporating yttrium into the structure. The photoelectrochemical characterisation shows that adding yttrium produces an enhanced charge separation efficiency in the bulk which can be attributed to a higher donor density in the structure, and a 92.5% higher photocurrent density is obtained for the 5%Y-CuWO4 photoelectrode when compared to the pure CuWO4 photoelectrode for the oxygen evolution reaction at 1.3 V vs RHE. This work shows that doping CuWO4 with yttrium is an effective approach to improve the poor charge separation presented by pure CuWO4 photoelectrodes.

Future progress in hybrid and battery vehicles heavily relies on the optimization of involved battery components and lubricants. Attention must specifically be given to the material composition and surface coatings of the electrodes as well as the electrolyte used to maximize energy output, while also ensuring safety. Additionally, prioritizing the effective utilization of specific lubricants for electric motors and various tribological contacts, such as wheel bearings and the steering system, is the prospective goal of lubrication research. The energy output of the most promising battery, the Li-ion battery (LIB), must result in driving ranges, which can compete with the 600 km driving range of combustion engine (ICE) vehicles. Consequently, ongoing research activities in cell chemistry, electrode surface engineering, electrolyte engineering, and engine lubrication offer the greatest opportunity in achieving these goals.

Mo,Cu-doped CeO 2 (CMCuO) nanopowders were synthesized by the nitrate-fuel combustion method aiming to improve the electrical and electrochemical properties of its Mo-doped CeO 2 (CMO) parent by the addition of copper. An electrical conductivity of ca. 1.22•10 -2 S cm -1was measured in air at 800 o C for CMCuO, which is nearly 10 times higher than that reported for CMO. This increase was associated with the inclusion of copper into the crystal lattice of ceria and the presence of Cu and Cu 2 O as secondary phases in the CMCuO structure, which also could explain the increase in the charge transfer activities of the CMCuO based anode for the hydrogen and carbon monoxide electro-oxidation processes compared to the CMO based anode. A maximum power density of ca. 120 mW cm -2 was measured using a CMCuO based anode in a solid oxide fuel cell (SOFC) with YSZ electrolyte and LSM-YSZ cathode operating at 800°C with humidified syngas as fuel, which is comparable to the power output reported for other SOFCs with anodes containing copper. An increase in the area specific resistance of the SOFC was observed after ca. 10 hours of operation under cycling open circuit voltage and polarization conditions, which was attributed to the anode delamination caused by the reduction of the Cu 2 O secondary phase contained in its microstructure. Therefore, the addition of a more electroactive phase for hydrogen oxidation is suggested to confer long-term stability to the CMCuO based anode.

The effects of the incorporation of Ti3C2Tx nano-sheets (MXenes) on the microstructure of SnO2/Ti electrodes and their electro-oxidation catalytic activity for the degradation of methyl red is studied in this work. MXenes-SnO2/Ti electrodes are fabricated by spin-coating followed by a thermal treatment under ambient atmospheric conditions using a solution containing MXene nano-sheets, SnCl2, citric acid and ethylene glycol as precursor. Energy-dispersive X-ray spectroscopy, Raman spectroscopy and Xray diffraction analyses of the MXenes-SnO2/Ti electrodes surface indicate the formation of SnO2-TiO2 films with Ti 4+ ions incorporated into the lattice of SnO2 crystals. Cyclic voltammetry curves demonstrate that the oxygen evolution reaction is restrained by the MXenes-SnO2/Ti electrodes, while the methyl red electro-oxidation is enhancedwith kinetics following a pseudo-first-order modelcompared to the performance of (pure) SnO2/Ti electrodes. These results suggest that oxygen vacancies are formed in the crystal lattice of MXenes-SnO2/Ti electrodes, which act as charge carriers and increase the electrical conductivity of SnO2 as confirmed by the lower charge transfer resistance of MXenes-SnO2/Ti electrodes determined by electrochemical impedance spectroscopy analysis.