Highly Active, Selective, and Stable Direct H₂O₂Generation by Monodispersive Pd–Ag Nanoalloy

Jin Zhang^†,Bolong Huang^*‡,Qi Shao^†, andXiaoqing Huang^*†（黄小青）

^†College of Chemistry, Chemical Engineering and Materials Science,Soochow University,Suzhou,Jiangsu215123,China

^‡Department of Applied Biology and Chemical Technology,The Hong Kong Polytechnic University, Hung Hom,Kowloon,Hong Kong SAR,China  

ACS Appl. Mater. Interfaces,2018,10(25), 21291--21296

Hydrogen peroxide (H₂O₂), a green oxidant, has wide applications in various chemical syntheses and is also a promising candidate to replace the traditional toxic oxidants. The direct synthesis of H₂O₂from H₂and O₂is a potential approach, as it is a green and atomically economic reaction. However, the most previous systems are notorious in complicated post-purification procedures, high energy cost, and low selectivity because of the uncontrollable O–O bond cleavage. We have solved this challenge by tuning the chemical state of Pd with high H₂O₂productivity of 80.4 mol kg_cat^–1h^–1and high H₂O₂selectivity of 82.1% via the design of Pd–Ag nanoalloys with flexibly tuned size and composition. The created Pd–Ag nanoalloy also exhibits excellent stability with limited performance decay over recycles. The X-ray photoelectron spectroscopy analysis confirms the electron transfer from Ag to Pd, which generates more Pd⁰and enables improved H₂O₂productivity. The theoretical calculation shows that the incorporation of Ag into Pd is beneficial for the stabilization of O₂^2–and the cleavage of H₂for the enhanced H₂O₂generation. In addition, the enhanced H₂O₂desorption on Pd–Ag nanoalloy is beneficial for releasing H₂O₂, which results in the increased H₂O₂selectivity.

链接：https://pubs.acs.org/doi/10.1021/acsami.8b03756