Controlled Synthesis of Bead‐like Pt as an Efficient Electrocatalyst for Electrocatalytic Ammonia Oxidation

Abstract

AbstractPromoting electrocatalytic ammonia oxidation reaction (AOR) holds the key to develop efficient direct ammonia fuel cells (DAFCs) and ammonia‐mediated hydrogen production (AMHP). Recent investigations indicated that Pt with the exposure of (100) facet has a moderate *N intermediate bonding strength, resulting in the highest AOR electrocatalytic activity among others. Therefore, maximizing the exposure of (100) planes with high active surface area is highly desired for efficient electrocatalysts. In this paper, Pt catalyst composed of directional alignment of nanoparticles around 50 nm (Pt‐100/C) were synthesized by hydrothermal method in the presence of KOH. The KOH concentration was found to modulate the one‐dimensional alignment of nanoparticles. The electrocatalyst showed the largest electrochemically active areas and the highest peak current density (3.14 mA cm−2), and the catalyst exhibited high stability after 500 cycles. A series of electrochemical tests and structural characterizations show that unique bead‐structured Pt combines the excellent activity of nanoparticles with the structural stability of nanowires. A scheme for “exchanging electrodes” has been proposed to solve the problem of catalyst poisoning caused by AOR in AMHP.