Nickel Silicide Catalyst from Photovoltaic Waste for the Methanation Reaction

A technology designed for recycling photovoltaic (PV) cells at the end of their life was successfully used for the preparation of a nickel silicide catalyst. PV cells were mixed with magnesium scrap to produce magnesium silicide (Mg2Si), with almost total conversion under optimized conditions (400 °C, 5 Pa, 25 min), in a constructed semi-open tubular reactor. Subsequently, magnesium silicide was hydrolyzed by 25% phosphoric acid to produce a mixture of silicon hydrides, which were utilized as chemical vapor deposition (CVD) precursors for the preparation of a nickel silicide catalyst. The activity and stability of the prepared catalyst was repeatedly tested for methanation reactions. It was verified that the nickel silicide catalyst showed an approximately 20% higher activity for the methanation reactions compared to the commonly used nickel catalyst.