Facile Synthesis of High Areal Density and Stable Pt Single-Atom Electrocatalysts by Arc Discharge Atomization and CoNi Trapping.

Pt-group metal single-atom catalysts (SACs) with a large single-atom areal density are highly desirable for efficient electrocatalysis but remain challenging to synthesize. Herein, a facile vacuum direct current arc discharge (DCAD) strategy is reported for the rapid and scalable synthesis of Pt SACs with an unprecedented areal density of 10.6 atoms nm (3.82 wt.% Pt loading) firmly anchored on CoNi nanoalloy and confined by carbon nanotubes (CoNiPt@G). Notably, due to the strong electron trapping effect between Pt SA and CoNi substrates, CoNiPt@G retains its structural integrity at 1000 °C, demonstrating an outstanding thermal stability despite the ultra-high areal density. Moreover, the DCAD strategy is universal, which can be applied to other metals such as Iridium. It is also scalable, with a demonstrated gram-scale yield achieved within 0.5 h. The resulting CoNiPt@G catalyst exhibits exceptional hydrogen evolution reaction performance, achieving an overpotential of 23 mV at 10 mA cm, a mass activity over 5 times higher than that of 20 wt.% Pt/C catalyst and high stability during the 120 h test. This work provides a groundbreaking pathway for the large-scale production of high single-atom areal density, thermally robust SACs, advancing their practical applications in clean energy technologies.