铁稳定的铂单原子催化选择性加氢反应

Iron-Stabilized Pt Single-Atom Catalysis for the Selective Hydrogenation

多相催化剂常以过渡金属为活性中心,当催化活性位点呈原子级分散时,金属利用率达到最高,故具有优异的催化性能。然而,铂族金属和惰性氧化物的结合较弱,所以在Al_(2)O_(3)和SiO_(2)之类的载体上,铂很难被分散成单原子的形式。使用简单的溶胶-凝胶法,在惰性氧化物中掺杂铁元素可显著增强铂与载体之间的共价相互作用,从而制得单原子铂催化剂。在苯乙炔选择性加氢生成苯乙烯的反应中,0.2 wt%PtFe_(50)/Al_(2)O_(3)-SiO_(2)单原子催化剂具有良好的选择性,其反应速率是0.2 wt%Pt/Al_(2)O_(3)-SiO_(2)纳米颗粒催化剂的1.4倍。该单原子催化剂还在循环测试中表现出高稳定性,证明了载体的掺杂改性是一种将活性金属分散在惰性氧化物上,得到高活性和高稳定性的单原子催化剂的有效策略。

The heterogeneous catalysts with isolated active metal centers at the atomic dispersion show the highest metal utilization,leading to superior catalytic activities.However,achieving the atomic dispersion of Pt-group metals on irreducible oxides,such as Al_(2)O_(3) and SiO_(2),is quite difficult.Consequently,the Al_(2)O_(3)-SiO_(2) support is modified by the Fe component to strengthen the interaction with Pt species.The single-atom Pt catalyst was fabricated using a simple sol-gel method,showing high selectivity for the hydrogenation of phenylacetylene to styrene.Besides,the reaction rate of 0.2 wt%PtFe_(50)/Al_(2)O_(3)-SiO_(2) single-atom catalyst is 1.4 times higher than that of 0.2 wt%Pt/Al_(2)O_(3)-SiO_(2) nanoparticle analogue.Moreover,the high stability of thus synthesized single-atom catalyst is proved by the recycling tests,demonstrating an efficient method to anchor single metal atoms on the modified inert oxide supports.