Electrocatalysis by Nanoparticle: Enhanced Electro-Oxidation of Formic Acid at NiO_x–Pd Binary Nanocatalysts

Abstract

This study addresses formic acid (FA) electro-oxidation (FAO) at a binary catalyst composed of palladium (PdNPs) and nickel oxide (nano-NiOx) nanoparticles electrodeposited onto a glassy carbon (GC) electrode. The deposition sequence of PdNPs and nano-NiOx onto the GC electrode is properly adjusted in such a way that maximizes the electrode efficiency toward FAO. The highest catalytic activity and stability are obtained at the NiOx/Pd/GC electrode (with PdNPs directly deposited onto the GC electrode followed with nano-NiOx with an optimum surface coverage, Γ, of ca. 41%). The enhancement is manifested in the increase of the oxidation peak current of FA together with a favorable negative shift of the onset potential of FAO. It is believed that nano-NiOx could facilitate the direct oxidation of FA via minimizing the amount of the poisoning species at the Pd surface.

Fabrication of CuOx-Pd Nanocatalyst Supported on a Glassy Carbon Electrode for Enhanced Formic Acid Electro-Oxidation

“…Table 2 summarizes the electrochemical parameters, extracted from Figures 5 and 6, of the CuO x /Pd/ GC compared with Pd/GC and Pd/CuO x /GC electrodes. It also compares the data obtained in this investigation with the same data obtained from other previous investigations at which Pt surface was modified with nano-NiO x and IrNPs [49,50].…”

Facile Synthesis of a Tailored-Designed Au/Pt Nanoanode for Enhanced Formic Acid, Methanol, and Ethylene Glycol Electrooxidation

“…Hydrogen, the lightest carbon-free fuel, has been the focus of fundamental and applied research for potential applications in HFCs. However, the high cost of miniaturized hydrogen containers; the potential risk associated with using, storing, and transporting hydrogen; and its low gas-phase energy density have driven the attention towards liquid fuels such as formic acid (FA) [7], methanol (M) [8], and ethylene glycol (EG) [9]. Interestingly, the FCs of these particular fuels have shown inherent features that excel from those of HFCs.…”

Intriguing Catalytic Activity of Surface Active Gold‐Platinum Islands on Nano‐Porous Au in Determining Efficient Direct Formic Acid Oxidation Pathway

“…Enhancing the electro‐catalytic activity of proton exchange membrane fuel cells (PEMFCs) catalysts using ultra‐low platinum group metal (PGM) content is one of the daunting challenges because PGMs are most effective for PEMFC electrode reactions but are less abundant . Among other PEMFC reactions, FAOR is gaining more importance because, it involves liquid formic acid as fuel and has additional advantages like high reversible cell voltage (1.48 V vs. RHE) and energy density at ambient conditions, safer handling compared to H 2 fuel and lower crossover compared to methanol . In commercialization point of view, FAOR catalysts with less PGM and maximal Pt utilization are highly needed for enhanced electrode kinetics .…”

“…The fundamental aspects of FAOR were studied on polycrystalline and single crystalline Pt and Au surfaces . Pd based, Ir/Pd catalyst and monometallic Au and Pt clusters modified glassy carbon based catalysts are employed for FAOR catalysis . However, monometallic PGMs like Pt and Pd are non‐selective and unstable towards FAOR, Particularly, FAOR on monometallic Pt happens through dual pathways (either dehydrogenation or dehydration pathway) .…”

“…Hence, there is a challenging need to develop a Pt based bimetallic catalysts which mitigate the indirect pathway and selective towards the most desired direct dehydrogenation FAOR pathway. The main expectations towards adding the second metal in Pt based FAOR catalyst is that; it should supress the CO adsorption/poisoning, improve FAOR selectivity towards direct dehydrogenation pathway and exhibit enhanced stability in acidic environment ,. In this regard, noble metal counterparts like Au, Pd, Ru and Ag are included with Pt to form Pt−Ru, Pd−Pt, Au−Pd, Au‐PdPt, Ag−Pt@Pt, and Au‐Pt projected as better FAOR catalysts owing to the ensemble and electronic effect .…”