Au/ZnO催化剂的制备及常温常湿条件下CO氧化催化性能

用共沉淀法制备了n(Au)/n(ZnO)=1.3/100的催化剂.考察了焙烧温度对Au/ZnO催化剂的化学组成及CO氧化性能的影响.结果表明,焙烧温度对催化剂的化学组成、活性和稳定性均有较大影响,其中240℃焙烧制得的Au/ZnO催化剂稳定性最好,在25℃和进料中含有水分的条件下,可连续反应600h使CO完全转化.XRD,FTIR,TG-DTA,TEM及UV-Vis结果表明,金粒子高度分散在氧化锌或碳酸锌上,平均直径2～5nm.催化剂的稳定性同锌物种有关,氧化锌较碳酸锌表现出较好的稳定性,且氧化锌粒子越小,比表面积越大,催化剂的稳定性越高.

Preparation of Au/ZnO Catalyst and Its Catalytic Performance for CO Oxida tion at Ambient Temperature and Moisture

The catalytic performance of Au/ZnO catalysts prepared by a coprecipitation method for CO oxidation at ambient temperature and moisture was studied. It was found that the chemical composition, the activity and the stability of the catalysts were greatly changed with the variation of calcination temperature. The sample calcined at 240 ℃ showed the best stability, i.e. it can maintain CO complete conversion for 600 h. XRD, FTIR, TEM and UV-Vis results indicated that gold could be highly dispersed on the surface of ZnCO3 or ZnO, with the mean diameter of gold particle being 2—5 nm. The type of support was the main influencing factors on the stability of Au/ZnO catalysts, the stability of ZnO supported gold catalysts was better than that of the ZnCO3 supported gold samples. The smaller of ZnO particle and the bigger of SBET, the better of the stability of Au/ZnO catalysts was obtained.