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In the context of waters polluted with different high-risk contaminants, the development of efficient materials able to efficiently clean them is necessary. In the first part, the present review focuses on the ability of various types of magnetic layered double hydroxide materials to act as adsorbents for water contaminated mainly with heavy metals and dyes. Also, this paper reviews the ability of different magnetic layered double hydroxide materials to act as potential adsorbents for the treatment of wastewater contaminated with other types of pollutants, such as pharmaceutical products, phenolic compounds, phytohormones, and fungicides. In the second part, the applicability of the catalytic method for water depollution is explored. Thus, the use of simple or composite materials based on Fe3O4 is reviewed for the purpose of the catalytic degradation of organic compounds (dyes/phenols/pharmaceuticals). At the end, a review of multifunctional materials able to simultaneously neutralize different types of pollutants from wastewater is provided. [ABSTRACT FROM AUTHOR]

In this study, we report the influence of the Pt concentration in CoxPt100−x alloys on the catalytic activity of the alloys for 4-nitrophenol (4-NP) reduction. More precisely, a series of CoxPt100−x alloys with a Pt concentration ranging between 60% and 95% were prepared using electrodeposition at controlled potentials from stable hexachloroplatinate aqueous solution. The Pt concentration was tuned by varying the electrodeposition potential from −0.6 to −0.9 V. The changes in the CoxPt100−x alloy microstructure and crystalline structure have been investigated using SEM and TEM analysis. Our results show that the microstructure and the crystalline structure of the as-prepared materials do not depend on the electrodeposition potential. However, the catalytic activity of CoxPt100−x alloys is closely correlated with the potential applied during electrochemical synthesis, hence the Pt content. We demonstrated that the synthesized materials present a high catalytic activity (approx. 90%) after six cycles of reusability despite the fact that the Pt content of the as-prepared alloys decreases. The easy preparation method that guarantees more than 97% catalytic activity of the CoxPt100−x alloys, the easy recovery from solution, and the possibility of reusing the CoxPt100−x alloys are the benefits of the present study. [ABSTRACT FROM AUTHOR]

The commercialization of the Direct Methanol Fuel Cell (DMFC) is limited due to the high cost and low efficiency of the electrocatalysts. In this context, the development of new electrocatalysts able to efficiently oxidize the methanol and to have at the same time low price and high stability is one of the researcher's milestones. In this work, CoPt alloys with different Pt content were prepared, and the efficiency of the alloys to be used as electrocatalysts for the methanol oxidation reaction (MOR) was investigated. Our data show that the electrocatalytic performance of the CoPt electrodeposited alloys is strongly influenced by the synthesis conditions, mainly by the potential applied during the synthesis. The best electrocatalytic activity was obtained for the samples prepared at −0.8 V/SCE. [ABSTRACT FROM AUTHOR]