Green Fabrication of Integrated Au/CuO/Oyster Shell Nanocatalysts with Oyster Shells as Alternative Supports for CO Oxidation

摘要

Oyster shells (OSs) are a kind of reusable resources which are largely discarded randomly as waste. In this study, we have employed OSs as rigid supports to fabricate integrated Au/CuO/OS nanocatalysts by chemical functionalization of the hydrophilic OS surface with 3-mercaptopropionic acid. The exposed mercapto groups on the OS surface facilitate the complexation of copper ions during the in situ growth of Cu-BTC on OSs. Both CuO/OS and Au/CuO/ OS obtained after calcination were evaluated for CO oxidation reaction which exhibited good catalytic activity with T-100% of 160 and 150 degrees C, respectively. More importantly, CuO/OS and Au/CuO/OS have excellent sintering resistance which can well maintain their original catalytic activity during 150 h test. The density functional theory calculation results further indicate the synergistic effects that exist between CuO and Au during CO adsorption and oxidation. The chemisorption energies of CO on the catalysts decrease in the following orders, -0.968 eV (CuO/CaCO3) > -1.169 eV (Au/ CuO) > -1.618 eV (Au/CuO/CaCO3), suggesting the enhanced adsorption of CO on Au/CuO/OS. The Bader charge calculation showed that one CO molecule obtained 0.405 electron from Au/CuO/CaCO3 which was much higher than those from other catalysts. Therefore, we have developed a cleaner method for catalyst production by the use of waste OSs.