Tailor-nanostructured iron oxide, gold and platinum ternary catalyst for boosted electrochemical oxidation of formic acid.

A robust catalyst for the electrochemical oxidation of formic acid (EOFA) was develop by depositing semi-spherical platinum nanoparticles (nano-Pt, <37 nm in diameters) as connected aggregates (ca. 106 nm in an average diameter) onto the surface of a glassy carbon (GC) rod (Pt/GC catalyst). This Pt/GC catalyst was further amended sequentially with spherical gold nanoparticles (nano-Au, ca. 50 nm in an average diameter) and iron oxide nanowires (nano-FeOx, ca. 30 nm in average diameter and 194 nm in average length). The layers' sequencing of the catalyst was critical in optimizing the catalyst's efficiency. Surprisingly, the modification of the Pt/GC catalyst first with nano-Au and next with nano-FeOx (FeOx/Au/Pt/GC catalyst) decreased the electrochemical surface area of nano-Pt ca. 16-times, which is highly desirable. Besides, it increased tremendously the activity (two-orders of magnitude), stability (ca. 18-fold) and tolerance against CO poisoning (7-times) of the catalyst for EOFA. Moreover, it saved up to ca. −236 mV in the onset potential of the "non-poisoning" dehydrogenation pathway of EOFA. It further retained a high mass activity of 300 A g−1. With the aid of multiple materials and electrochemical inspections, the catalyst's development was confirmed and the role of catalytic ingredients was elucidated. Interestingly, nano-Au hindered geometrically the adsorption of poisoning CO molecules onto the Pt surface, whereas nano-FeOx improved significantly the charge transfer kinetics of EOFA while mediating a faster mechanism. [Display omitted] • A nanostructured FeOx/Au/Pt/GC catalyst was successfully developed. • It boosted (2 order of magnitude) the activity toward the electrochemical oxidation of formic acid (EOFA). • It owned an improved stability (ca. 18-fold) and tolerance against CO poisoning (7-times), in relative to the Pt/GC catalyst. • It saved up to ca. −236 mV in the onset potential of the "non-poisoning" dehydrogenation pathway of EOFA. [ABSTRACT FROM AUTHOR]