Cyclic voltammetry electrodeposition of well-dispersed Pd nanoparticles on carbon paper as a flow-through anode for microfluidic direct formate fuel cells.

The preparation of low-loading and high-performance Pd-based electrodes is required for direct formate fuel cells. In this study, cyclic voltammetry electrodeposition is used to electrodeposit Pd nanoparticles on carbon paper (Pd/CP) and achieve excellent activity and promising stability toward the formate oxidation reaction (FOR). The prepared electrode shows a thin layer of hemispherical and well-dispersed Pd nanoparticles on the fibers of the carbon paper. The open structure and uniform catalyst distribution make the Pd/CP electrode show 2.56-fold higher active area and stability in the FOR as compared with those of commercial Pd/C catalysts. An air-breathing microfluidic direct formate fuel cell (μDFFC) with a Pd/CP electrode used as a flow-through anode is constructed to further assess electrode performance. The Pd/CP electrode with low Pd loading, 0.105 mg cm-2, delivers a peak power density and limiting current density of 46.6 mW cm-2 (443.8 mW mg-1Pd) and 288.4 mA cm-2, respectively. The performance of the μDFFC is superior to those of most others reported in the literature, further boosting the commercialization of this direct formate fuel cell to power next-generation portable electronics.