Cuprous nanoparticles (NPs) on multi-walled carbon nanotubes (MWCNTs) were synthesized by the room-temperature-ionic-liquid-assisted sputtering deposition. The obtained hybrids were systematically characterized by high-resolution transmission electron microscopy (HRTEM), high-angle annular dark scanning TEM (HAADF-STEM), X-ray photoemission spectroscopy (XPS) and Raman spectroscopy. The supported Cu2O-MWCNTs hybrids were highly catalytically active for reduction of 4-nitrophenol with a degradation efficiency of 100% after reaction time of 12min, a high level competitive with the reported noble metal catalysts. It is significant for practical catalysis since the non-precious metal-based catalysts can be easily prepared by the present approach.