Nanomaterials are of interest due to their potential applications in catalysis and sensing. Specifically, transition-metal chalcogenide based nanostructures have attracted wide attention due to their tailorable physical and chemical properties. In our work, degeneratively doped copper chalcogenide (Cu2-xSe) semiconductor nanoparticles have been investigated as catalysts in various redox reactions using organic dyes that differ in their redox potentials. Due to the high concentration of free holes ascribed to copper oxidation, Cu2-xSe nanoparticles are expected to be good electron acceptors facilitating electron transfer involved in redox reactions. The catalytic reduction mechanisms of methylene blue, methyl orange and 4-nitrophenol molecules have been investigated in aqueous and air-free conditions by absorption spectroscopy using several sacrificial reducing agents (e- donors). The best catalytic activities are found for dyes showing a reduction potential more positive than the conduction band energy of Cu2-xSe. However, reactivity decreases drastically when the oxidation potential of the sacrificial e- donor becomes more positive. In accordance with these results, the reduction mechanism and implication of intermediate species will be discussed. We highlight that these reactions are sensitive to experimental conditions. For example, the presence of electron scavengers, e.g. O2, can inhibit the kinetics of the reaction, and the rapid degradation of reducing agents as a function of time at low concentration (or low pH) has to be carefully taken into account. In this vein, we will also report a hole driven catalytic oxidation of organic molecules using Cu2-xSe nanomaterials.

Catalytic applications of Cu2-xSe nanoparticles in redox reactions

254th National Meeting (2017)

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