柠檬酸量对水热合成CuO/Ce_(0.8)Zr_(0.2)O_(2)催化水气变换制氢性能的影响

Effect of citric acid content on the hydrothermal synthesis of CuO/Ce_(0.8)Zr_(0.2)O_(2) catalytic water gas shift hydrogen production performance

采用水热法合成了Ce_(0.8)Zr_(0.2)O_(2)固溶体,再经浸渍法负载活性组分制备了CuO/Ce_(0.8)Zr_(0.2)O_(2)催化剂,考察了柠檬酸量对CuO/Ce_(0.8)Zr_(0.2)O_(2)催化剂结构、性质及其催化水气变换反应制氢性能的影响。结果表明,不同柠檬酸量制备的CuO/Ce_(0.8)Zr_(0.2)O_(2)催化剂的催化活性主要与Cu比表面积、还原性能及Ce_(0.8)Zr_(0.2)O_(2)固溶体与CuO之间的相互作用有关。其中,柠檬酸浓度为0.04 mol/L所制备的催化剂具有较大的Cu比表面积,较低的CuO还原温度和较强的Ce_(0.8)Zr_(0.2)O_(2)固溶体与CuO之间的相互作用,在水气变换制氢过程中具有较高的CO转化率,表现出了较好的催化活性。在反应温度为320℃,水气物质的量比n(H_(2)O)/n(CO)=2,总气体体积空速GHSV=6600 h^(−1)时,CO转化率接近热力学平衡值,为96.9%。

Ce_(0.8)Zr_(0.2)O_(2) solid solutions were synthesized by hydrothermal method,and active components were loaded by impregnation method to get CuO/Ce_(0.8)Zr_(0.2)O_(2) catalysts.Effects of citric acid content on the structure,properties and hydrogen production performance of CuO/Ce_(0.8)Zr_(0.2)O_(2) catalysts were investigated.CuO/Ce_(0.8)Zr_(0.2)O_(2) catalysts prepared with different citric acid content are distinct in Cu surface area,reduction performance and interaction between Ce_(0.8)Zr_(0.2)O_(2) solid solution and CuO.Among them,the catalyst prepared with a citric acid concentration of 0.04 mol/L has a large Cu surface area,a low CuO reduction temperature and a strong interaction between Ce_(0.8)Zr_(0.2)O_(2) solid solution and CuO,which has the best catalytic activity and the highest CO conversion in the water gas shift conversion process.At 320℃,water/gas molar ratio n(H_(2)O)/n(CO)=2,total volume velocity GHSV=6600 h^(−1),its CO conversion is 96.9%close to thermodynamic equilibrium value.