Dynamically self-assembled adenine-mediated synthesis of pristine graphene-supported clean Pd nanoparticles with superior electrocatalytic performance toward formic acid oxidation

Pd-based catalysts with maximized exposure of active sites, ultrafast electron transport, and cocatalyst-promoted intrinsic activity are highly desirable for the formic acid oxidation reaction (FAOR), but their fabrication presents a formidable challenge. For the first time, dynamic self-assembly of adenine has been utilized for growth of ultrasmall, highly dispersed, and clean Pd NPs on pristine graphene. The obtained nanohybrid shows remarkably enhanced FAOR catalytic activity and durability compared to Pd NPs directly grown on pristine graphene and commercial Pd/C. The activity is also among the highest for Pd-based catalysts. The excellent catalytic performance is due to well-dispersed, ultrasmall, and clean Pd NPs intimately grown on pristine graphene offering numerous electrochemically accessible active sites and preserving high intrinsic catalytic activity of Pd, great cocatalytic effect of pristine graphene enhancing CO tolerance and intrinsic activity of Pd, and robust attachment of Pd with high CO tolerance on graphene providing high durability. This study develops a facile, mild, and economical strategy to create pristine graphene supported clean Pd NPs with outstanding FAOR catalytic performance, and also sheds light on the mechanism of dynamically self-assembled adenine-mediated synthesis, which is extendable to fabricate other nanohybrids.