Conversion of Pt nanoparticles encapsulated within MIL-101(Fe) to FePt intermetallic nanoparticles supported on carbon promotes formic acid electrooxidation

Abstract Pt-based catalysts have limited usefulness in direct formic acid fuel cells (DFAFCs) due to their susceptibility to CO poisoning. Combining Pt with Fe atoms is an effective approach for suppressing Pt poisoning by CO. In this work, we fabricate novel carbon-supported FePt alloy nanoparticles (FePt@C) by pyrolyzing Pt nanoparticles encapsulated within mesoporous MIL-101(Fe) (Pt@MIL-101(Fe)). The resulting FePt nanoparticles (Fe3Pt (111)) possess a lower CO adsorption energy (0.64 eV) than the (111) surfaces of Pt, indicating that the FePt nanoparticles are far less susceptible to CO poisoning. The mass activity and current density of a 9.6 wt.% FePt@C catalyst are 4.2 and 4.5 times, respectively, higher than those of a commercial Pt/C catalyst. Furthermore, the 9.6 wt.% FePt@C catalyst exhibits excellent durability, with only a 0.1% loss of mass activity after 1,000 cycles. These results should guide the development of improved anode catalysts for DFAFCs based on MOF precursors.