CuCl2 promoted low-gold-content Au/C catalyst for acetylene hydrochlorination prepared by ultrasonic-assisted impregnation

CuCl2 promoted low-gold-content Au/C catalyst for acetylene hydrochlorination prepared by ultrasonic-assisted impregnation

A detailed study of low-gold-content Au(0.25%)/C and Au(0.25%)Cu(4%)/C catalysts prepared viaultrasonic-assisted impregnation method is described and discussed. The addition of 4 wt% Cu to Au/Cincreases the initial activity and the Au loading is decreased to 0.25 wt%. Au(0.25%)Cu(4%)/C exhibits bestcatalytic performance with an acetylene conversion of 97.4% and the selectivity to VCM of more than 99%at a space velocity of 720 h 1 and 150 8C. The observations are rationalized in terms: (i)Au(0.25%)Cu(4%)/C exhibits relative larger specific surface area (562 m2/g) than Cu(4%)/C (385 m2/g),which provides more active sites for acetylene hydrochlorination; (ii) the reduction activation energy ofAu3+! Au0 in Au(0.25%)Cu(4%)/C (45.5 kJ/mol) is much higher than that of Au(0.25%)/C (35.6 kJ/mol),which indicates that the Au3+ species in Au(0.25%)Cu(4%)/C catalyst is more difficult to be reduced, thereduction activation energy of Cu+! Cu0 in Au(0.25%)Cu(4%)/C (48.9 kJ/mol) is higher than that ofCu(4%)/C (43.1 kJ/mol) as a result of the electronic interaction between Au and Cu atoms; (iii)Au(0.25%)Cu(4%)/C possesses more Au3+ species (28%) than Au(0.25%)/C (16%) determined by XPS. Freemercurylow-gold-content Au(0.25%)Cu(4%)/C catalyst is environmental-friendly, making it apotentially green catalyst for acetylene hydrochlorination.

A detailed study of low-gold-content Au(0.25%)/C and Au(0.25%)Cu(4%)/C catalysts prepared viaultrasonic-assisted impregnation method is described and discussed. The addition of 4 wt% Cu to Au/Cincreases the initial activity and the Au loading is decreased to 0.25 wt%. Au(0.25%)Cu(4%)/C exhibits bestcatalytic performance with an acetylene conversion of 97.4% and the selectivity to VCM of more than 99%at a space velocity of 720 h 1 and 150 8C. The observations are rationalized in terms: (i)Au(0.25%)Cu(4%)/C exhibits relative larger specific surface area (562 m2/g) than Cu(4%)/C (385 m2/g),which provides more active sites for acetylene hydrochlorination; (ii) the reduction activation energy ofAu3+! Au0 in Au(0.25%)Cu(4%)/C (45.5 kJ/mol) is much higher than that of Au(0.25%)/C (35.6 kJ/mol),which indicates that the Au3+ species in Au(0.25%)Cu(4%)/C catalyst is more difficult to be reduced, thereduction activation energy of Cu+! Cu0 in Au(0.25%)Cu(4%)/C (48.9 kJ/mol) is higher than that ofCu(4%)/C (43.1 kJ/mol) as a result of the electronic interaction between Au and Cu atoms; (iii)Au(0.25%)Cu(4%)/C possesses more Au3+ species (28%) than Au(0.25%)/C (16%) determined by XPS. Freemercurylow-gold-content Au(0.25%)Cu(4%)/C catalyst is environmental-friendly, making it apotentially green catalyst for acetylene hydrochlorination.