Solvent effects on arc discharge fabrication of durable silver nanopowder and its application as a recyclable catalyst for elimination of toxic p-nitrophenol

• Long-lasting, low cost silver nanopowder (AgNP) is produced by arc discharge.
• The recyclable AgNP is used as a heterogeneous catalyst for purification of water.
• Highly toxic p-nitrophenol is efficiently converted to p-aminophenol by AgNP.
• Hydrogen is produced in the process as a clean source of energy from polluted water.

Various types of nanosilver have been synthesized by a variety of methods, among them “arc discharge” stands with numerous advantages and calls for a much higher attention. Here, an unprecedented durable powder form of silver nanopowder (AgNP) is produced by DC arc discharge through a simple, convenient, and economical route, at a current of 5–10 A/cm2. Effects of media are probed against the quality of the resulting nanoparticles. Among eleven media explored, glycerin/water (10% w/w) is found to afford the highest yield, purity, and relatively smaller size of AgNP with the desired morphology. To our joy, the as-prepared-AgNP proves efficient in catalytic green reduction of p-nitrophenol (PNP) which is one of the most potent water pollutants. Our reduction of PNP by NaBH4 in the presence of AgNP in water is monitored by UV–Vis spectrophotometry. A provisional mechanism is proposed for this reaction which appears fast and completes in two minutes. The AgNP is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Hence, arc discharge fabrication of durable AgNP is maximized by adapting glycerin/water as the medium of choice; and the resulting AgNP catalyzes toxic PNP conversion into p-aminophenol.