Improved Electrocatalytic Performance of Multiwalled Carbon Nanotube‐Anchored Au‐Based Bimetallic Catalysts Au–X (X = Cu, Fe, and Sn) for Direct Borohydride Fuel Cells

The development of cost‐effective and high‐performance electrocatalysts for the borohydride oxidation reaction (BOR) is crucial to enhancing the efficiency of direct borohydride fuel cells (DBFCs). In this study, Au–X (Fe, Cu, and Sn) nanoparticles supported on multiwalled carbon nanotubes (MWCNTs) are prepared at room temperature and evaluated as anode electrocatalysts. The catalysts are thoroughly characterized using Raman spectroscopy, energy‐dispersive spectroscopy (EDX), field‐emission scanning electron microscopy (FESEM), X‐ray diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS). Incorporating bimetallic nanoparticles into MWCNTs markedly improves the borohydride electrooxidation activity, with the AuCu/MWCNT catalyst exhibiting the most outstanding performance among all tested electrocatalysts. The AuCu/MWCNT catalyst possesses a crystallite size of 14.3 nm, an electrochemically active surface area (ECSA) of 2953.43 cm 2 mg −1 , a highest current density of 27.35 mA cm −2 , a higher turnover frequency 0.06 s −1 , and a low activation energy of 4.5 kJ mol −1 , along with the lowest charge transfer resistance of 61.5 ohms. In single‐cell DBFC evaluations conducted at 303 K, the AuCu/MWCNT catalyst achieves a maximum power density of 24.46 mW cm −2 and a current density of 36 mA cm −2 . These findings highlight the superior catalytic efficiency and economic advantage of AuCu/MWCNT, underscoring its potential as a durable electrocatalyst for next‐generation DBFC systems.