PdCl2-loading mesoporous copper oxide (PdCl2/mCuO) catalysts were successfully synthesized via a hard template with copper carbonate basic (Cu-2(OH)(2)CO3), cupric nitrate (Cu(NO3)(2)center dot 3H(2)O) and copper citrate (Cu2C6H4O7 center dot 2.5H(2)O) as the copper(II) precursors, respectively. Their catalytic performances were investigated in the synthesis of diethyl carbonate (DEC) by oxidative carbonylation of ethanol with CO and O-2. The catalysts were characterized by TGA, XRD, nitrogen adsorption-desorption analysis and SEM with the aim of establishing their composition, morphology and structure. It was observed that the catalysts all showed a good selectivity to diethyl carbonate. However, due to a better mesoporous structure such as a bigger surface area, more uniform particle size and less agglomeration, the PdCl2/mCuO-1 catalyst prepared with Cu-2(OH)(2)CO3 precursor showed a better catalytic activity that the conversion of EtOH was about 4.8% and the STY of DEC was 97.1 mg g(-1) h(-1). This was because the highly developed mesoporous structure could generate a bigger surface area, which benefited the contact between reactants and active sites, improved the conversion of ethanol, and thus enhanced the catalytic performance. Furthermore, a synthetic procedure diagram about "wet impregnation" method of mesoporous CuO prepared with Cu-2(OH)(2)CO3 precursor was given to illustrate these results intuitively. (C) 2015 Elsevier B.V. All rights reserved.