and Na2CO3 were all analytical reagents and
purchased
from Beijing Chemical Plant. Methanol, ethanol, 1-propanol, and tert-butyl
alcohol were all analytical grade and purchased from Fuchen Chemical
Plant in Tianjin, China. AgNO3 and HAuCl4·3H2O and MgO nanoparticles (the mean particle size was 50 nm)
were purchased from Aladdin Industrial Co.