DeNOx activity of Ag/c–Al2O3 nanocomposites prepared via the solvothermal route

Ag/c–Al2O3 with silver loading of 3 wt.% were prepared by the solvothermal-calcination reaction of AgNO3 in mixed water-alcohol solutions at 50–250 C for 0–120 min, followed by calcinations at 550 C for 2 h using c-Al2O3 (SSA: 120–409 m2 g–1), c-AlOOH (SSA: 270 m2 g–1), Al(OH)3 (SSA 10 m2 g–1), Al(OCH(CH3)2)3 and Al(NO3)3 as an aluminum source. The resultant product produced by the solvothermal reaction was Ag/ c–AlOOH even though a different aluminum source was used and Ag/c–AlOOH was converted to Ag/c–Al2O3 by the following calcinations. However, the characteristics of them changed greatly depending on the alumina source. The deNOx catalytic performance of Ag/c–Al2O3 also greatly changed depending on the aluminum precursor and solvothermal solvent in the order c-AlOOH = c-Al2O3 >> Al(OCH(CH3)2)3 >> Al(NO3)3 > Al(OH)3 and methanol = ethanol > 1-propanol > butanol >> hexanol, since the amount and size of silver particle impregnated and specific surface area of the product changed markedly. Ag/c–Al2O3 prepared by solvothermal-calcination method consisted of homogeneously dispersed fine particles of silver and showed better performance for NOx decomposition than that by conventional impregnation-calcination method