Ultrafine copper nanoparticles anchored on reduced graphene oxide present excellent catalytic performance toward 4-nitrophenol reduction

[Display omitted] •Positively charged CuxO colloidal NPs are fabricated by LAL technique.•LAL-induced CuxO bond with GO by a static-electric interaction.•Ultrafine Cu NPs (2.0 ± 0.4 nm) with good dispersion anchored on rGO.•Higher catalytic activity of Cu/rGO than most reported pure Cu catalysts toward reduction of 4-NP. Downsizing copper nanoparticles (Cu NPs) can effectively improve their catalytic activity, but simultaneously ensuring the structural stability is always a challenge. In this study, by laser ablating a Cu target in graphene oxide (GO) solution along with a reduction treatment, pure Cu NPs (2.0 ± 0.4 nm) are evenly scattered on reduced graphene oxide (rGO). As-prepared Cu/rGO nanocomposites (NCs) are applied as catalysts for 4-nitrophenol (4-NP) reduction, which display high values of mass-normalized rate constant (k/m, 3.118 s−1 mgCu−1) and turnover frequency (TOF, 2.987 × 10−4 mmol mgCu−1 s−1), over those of most reported Cu catalysts. In addition, owing to the stable conjugation between ultrafine Cu NPs and rGO, the Cu/rGO catalysts reveal good catalytic stability that the conversion efficiency of 4-NP is still over 92.0% even after 10 successive cycles.