Abstract
Direct methanol fuel cells (DMFCs) are strong candidates for portable power generation due to their high energy density and simple system architecture. However, they have not become widespread due to platinum cost, CO poisoning, and limited durability. This review reevaluates methanol oxidation reaction (MOR) anode catalysts based on the fundamental surface processes that determine reaction rate (CO binding, OH∗ formation, and charge transfer), rather than simply classifying them by material type. Alloying, support engineering, and surface functionalization approaches have been shown to be interdependent components of the same performance architecture. While Pt-alloys provide a high activity-durability balance, Pd- and Ni-based systems have been found to offer cost-advantaged alternatives, particularly in alkaline environments. The relationship between electrochemical performance, platinum usage, and system lifetime has been jointly addressed from a techno-economic perspective, proposing a feasible roadmap for the design of low-Pt and Pt-free anodes. This approach aims to accelerate the transition of DMFC technologies from the laboratory scale to practical applications.
A comprehensive schematic illustration summarizing the design rationale for low-Pt and Pt-free anode electrocatalysts for the methanol oxidation reaction (MOR) in direct methanol fuel cells (DMFCs) and the key research areas highlighted in the literature. At the center, the fundamental bottleneck defined by the strong adsorption of COads species on Pt-based anode surfaces, high platinum cost, and limited durability is presented. The peripheral modules respectively illustrate: (i) the role of carbon, advanced/hybrid carbon, and non-carbon supports in MOR performance, (ii) how functionalization with oxygen, nitrogen, and other heteroatoms modulates metal–support interactions and CO tolerance, (iii) how metallic, oxide, and photo-supported promoters facilitate CO removal through bifunctional and ligand effects, (iv) the position of low-Pt alloys, Pd- and Ni-based systems, and alternative/hybrid active phases in the performance–cost balance, and (v) the simultaneous effects of platinum loading, durability, and stack lifetime on techno-economic feasibility. The general framework emphasizes that the joint optimization of support engineering, surface functionalization, promoter integration, and active phase selection is critical to achieving sustainable, economical, and high-performance anode designs in DMFCs.