铈掺杂对α-Bi_(2)Mo_(3)O_(12)纳米片催化剂丙烯选择性氧化性能的影响

Effect of cerium doping on performance ofα-Bi_(2)Mo_(3)O_(12) nanosheet catalysts for selective oxidation of propylene

采用快速微波辅助水热法制备了4种不同的Bi_(2-x)Ce_(x)Mo_(3)O_(12)纳米片催化剂。在制备过程中通过调节铈的掺杂量可以改变合成催化剂的形貌和结构,成功地提高了Bi_(2-x)Ce_(x)Mo_(3)O_(12)纳米片催化剂的比表面积。结果表明,煅烧温度为500℃、pH为3、掺杂量x=0.05时制备的Bi_(2-x)Ce_(x)Mo_(3)O_(12)纳米片催化剂具有最高的丙烯选择性氧化性能,丙烯转化率为42.1%,丙烯醛选择性为88.3%。Bi_(2-x)Ce_(x)Mo_(3)O_(12)纳米片催化剂的性能与结晶度呈负相关。用XPS表征了Bi_(2-x)Ce_(x)Mo_(3)O_(12)的氧迁移率,Bi_(2-x)Ce_(x)Mo_(3)O_(12)的催化性能与其氧流动性呈正相关。

Four kinds of Bi_(2-x)Ce_(x)Mo_(3)O_(12) nanosheet catalysts are prepared by rapid microwave assisted hydrothermal method.The surface area of catalysts is successfully increased through adjusting the doped amount of cerium to change the morphology and structure of the synthesized catalysts.It is shown by the results that Bi_(2-x)Ce_(x)Mo_(3)O_(12) nanosheet catalyst prepared at a calcination temperature of 500℃,a pH of 3 and a doping amount of 0.05 exhibits the highest performance for selective oxidation of propylene,delivering a propylene conversion of 42.1%and an acrolein selectivity of 88.3%.The performance of the catalyst is negatively correlated with its crystallinity,because higher crystallinity will inhibit the flow of lattice oxygen between the lattices,thus inhibiting the selective oxidation and reducing the conversion rate of the reaction.The oxygen mobility of Bi_(2-x)Ce_(x)Mo_(3)O_(12) is characterized by XPS.The catalytic performance of Bi_(2-x)Ce_(x)Mo_(3)O_(12) is positively correlated with its oxygen fluidity.