The Cu/CuxO nanoarchitectures with 30-70 nm hollow nanospheres are successfully synthesized by a facile wet chemical method. The synthesized products have been studied by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermo gravimetric-differential scanning calorimetry (TG-DSC) analysis. The Cu/CuxO sensors based on the nanoarchitectures are used to detect the NOx at room temperature. The results demonstrate that the obtained Cu/CuxO nanoarchitectures reduced by 3 mmol NaBH4 exhibits excellent gas-sensing properties: low detection limit of 0.97 ppm, relatively high sensitivity, short response time, broad linear range and high selectivity. The reasons for gas-sensing activity enhancement on Cu/CuxO nanoarchitectures are discussed. The Cu/CuxO nanocrystalline with the hierarchical pores structure and tunable compositions have significant for application of gas sensor. (c) 2013 Elsevier Ltd. All rights reserved.