Recent advances in electrocatalysts, mechanism, and cell architecture for direct formic acid fuel cells

Abstract

Direct formic acid fuel cells (DFAFCs) are potential candidates as power sources for various applications, especially in portable electronics and medical diagnostic devices. Though they have been the subject of considerable research, commercial prototypes of DFAFCs are rudimentary compared to other liquid fuel cells, particularly the widespread methanol‐based direct methanol fuel cells. Various strategies for rationally engineering the electrocatalysts for enhancing DFAFC performance have been explored in the last few years, such as alloying noble metals with earth‐abundant transition metals, designing specific morphological and structural arrangements, decorating the surface with corrosion‐tolerant cocatalysts, and providing better catalyst support for effective catalyst dispersion. An overall approach may be necessary and should include (i) understanding the underlying mechanism, which will guide the direction of catalyst engineering, (ii) employing morphological, compositional, and structural control of the electrocatalysts to improve catalyst utilization and enhance the intrinsic activity for real‐world applications, and (iii) integrating these in a proficiently designed cell architecture suitable for targeted applications. In this review, we focus on the recent advances in electrocatalysts, formic acid electrooxidation mechanisms, and DFAFC cell architectures, which could help address the opportunities and challenges of commercializing DFAFC as a prospective alternative power source for portable applications. This article is categorized under: Fuel Cells and Hydrogen > Science and Materials Energy Research & Innovation > Science and Materials

Recent Advances in Anode Electrocatalysts for Direct Formic Acid Fuel Cells – Part I – Fundamentals and Pd Based Catalysts

“…The main source of the electrical energy in a DFAFC is electrooxidation reaction of formic acid at the anode side. It is well established now that the electrooxidation of the formic acid takes place via a dual pathway including either a direct pathway (dehydrogenation) or indirect pathway (dehydration) [21,41,42] . The two mechanisms were first proposed by Capon and Parson in 1973 [43–45] .…”

“…Iron is one of the cheapest and most abundant metals in the world [188] . Bimetallic PdFe nanomaterials are highly effect active catalyst for FAO [21] . Fe improves the performance of the Pd catalysts through bifunctional mechanism.…”

“…It is well established now that the electrooxidation of the formic acid takes place via a dual pathway including either a direct pathway (dehydrogenation) or indirect pathway (dehydration). [21,41,42] The two mechanisms were first proposed by Capon and Parson in 1973. [43][44][45] In the direct or dehydrogenation mechanism, formic acid is firstly adsorbed on the metal surface forming an active intermediate that eventually results in CO 2 .…”

“…The vapor phase toxicity of methanol further inhibits its commercial utilization. These limitations have motivated researchers to look for other feeds such as formic acid [21] …”

Catalyst Composites of Palladium and N-Doped Carbon Quantum Dots-Decorated Silica and Reduced Graphene Oxide for Enhancement of Direct Formic Acid Fuel Cells

“… 4 It is an active metal element for formic acid adsorption and is regularly utilized as an electrocatalyst owing to its high tolerance to acidic condition. 1 , 4 …”