Remarkable direct formic acid electrocatalysis enabled by rare earth-doped platinum-tellurium heterostructures

Abstract The lack of new high-efficiency platinum (Pt)-based nanomaterials remains a formidable and exigent challenge in achieving high formic acid oxidation reaction (FAOR) and membrane electrode assembly (MEA) catalysis for direct formic acid fuel cell (DFAFC) technology. Herein, by adopting a synergistic amalgamation strategy, we report 16 types of Pt-based heterophase nanotrepang with rare earth (RE)-doped face-centered cubic Pt (fcc-Pt) and trigonal Pt-tellurium (t-PtTe2) configurations ((RE-Pt)-PtTe2 HPNT) to largely boost the FAOR and MEA catalysis. Comprehensively considering all the non-radioactive RE elements, yttrium (Y) is demonstrated to be the optimized doped element, coexisting as the forms of single site and cluster on the surface. The resulted (Y-Pt)-PtTe2 HPNT/C exhibits a competitive mass activity of 6.4 A mgPt-1, outperforming commercial Pt/C by 50.5 times. Simultaneously, it achieves the normalized MEA power density of 281.9 W gPt-1, 2.4 times higher than that of commercial Pt/C, demonstrating a large potential for DFAFC device application. The experimental findings evidence the key role of beneficial surface compositions of Y-doped fcc-Pt and t-PtTe2, significantly hindering the formation of CO intermediate and promoting the reaction kinetics. Density functional theory calculations further reveal the efficacy of Y doping, which predominantly locates on the high-energy Pt (110) facet and heightens the binding energy barrier with CO intermediate. The dehydrogenation pathway can be effectively promoted by enhancing the decomposition of formic acid and accelerating the conversion of reaction intermediates, resulting in the remarkable direct FAOR performance. This work achieves the high electrocatalysis in both FAOR and MEA media, highlighting the profound importance of RE metals served as favorable doping forms in heterostructure regulation of newly-designed Pt-based anodic nanomaterials for fuel cells and beyond.