Synergistic effect in an Au-Ag alloy nanocatalyst: CO oxidation.
Au-Ag alloy nanoparticles supported on mesoporous aluminosilicate have been prepared by one-pot synthesis using hexadecyltrimethylammonium bromide (CTAB) both as a stabilizing agent for nanoparticles and as a template for the formation of mesoporous structure. The formation of Au-Ag alloy nanoparticles was confirmed by X-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, and transmission electron microscopy (TEM). Although the Au-Ag alloy nanoparticles have a larger particle size than the monometallic gold particles, they exhibited exceptionally high activity in catalysis for low-temperature CO oxidation. Even at a low temperature of 250 K, the reaction rate can reach 8.7 x 10(-6) mol.g(cat.)(-1).s(-1) at an Au/Ag molar ratio of 3/1. While neither monometallic Au@MCM-41 nor Ag@MCM-41 shows activity at this temperature, the Au-Ag alloy system shows a strongly synergistic effect in high catalytic activity. In this alloy system, the size effect is no longer a critical factor, whereas Ag is believed to play a key role in the activation of oxygen.
Liu
Jun-Hong
JH
Wang
Ai-Qin
AQ
Chi
Yu-Shan
YS
Lin
Hong-Ping
HP
Mou
Chung-Yuan
CY
D000497:Alloys / Q000737:chemistry*; D000538:Aluminum Silicates / Q000138:chemical synthesis / Q000737:chemistry; D002248:Carbon Monoxide / Q000737:chemistry*; D002384:Catalysis; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D010316:Particle Size; D016062:Porosity; D012834:Silver / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors
D000497:Alloys; D000538:Aluminum Silicates; D002593:Cetrimonium Compounds; C049037:aluminosilicate; D012834:Silver; D006046:Gold; D002248:Carbon Monoxide; D000077286:Cetrimonium