Single-atom catalysts (SACs) have emerged as one of the most promising frontiers in heterogeneous catalysis owing to their maximal atom utilization efficiency, well-defined active sites, and tunable electronic structures. [1], [2] Nevertheless, achieving both high metal loading and atomic dispersion while maintaining stability and scalability remains a formidable challenge, particularly for noble metals such as platinum. Conventional wet-chemical routes often involve complicated procedures, long synthesis durations, and limited yields, restricting large-scale production. [3], [4] Developing a rapid, universal, and cost-effective method to fabricate SACs with high areal density and structural robustness is therefore of great significance for advancing industrial electrocatalysis and sustainable hydrogen energy technologies.
Herein, we report a facile one-step vacuum direct current arc discharge (DCAD) strategy that enables the gram-scale synthesis of high areal density Pt single-atom catalysts (10.6 atoms nm-2, 3.82 wt% Pt loading) within 30 minutes. In this process, PtO2, Co, Ni, and carbon precursors are atomized at high temperature (~6000 K) and rapidly quenched, forming Pt single atoms confined on CoNi nanoalloys encapsulated by carbon nanotubes (CoNiPtSA@G). The CoNi substrate acts simultaneously as an electron reservoir and atomic trap, ensuring uniform dispersion and exceptional stability of Pt atoms. Advanced characterizations confirm the atomic-level distribution and strong Pt-M (M = Co, Ni) coordination. The catalyst exhibits remarkable hydrogen evolution reaction (HER) activity with an overpotential of 23 mV at 10 mA cm-2, surpassing commercial 20 wt% Pt/C by over fivefold in mass activity, along with outstanding durability (120 h without Pt agglomeration). Density functional theory calculations reveal the strong electron transfer from CoNi alloy substrate to Pt atoms. Notably, due to the strong electron trapping effect between Pt SA and CoNi substrates, CoNiPtSA@G retains its structural integrity at 1000 ℃, 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.
This work demonstrates a universal, scalable, and time-efficient strategy for fabricating thermally stable, high-density single-atom catalysts through the DCAD approach. By integrating atomization, trapping, and self-assembly in one step, the strategy eliminates the need for complex chemical synthesis and enables rapid, large-scale production. The proposed methodology not only advances the rational design of Pt-based SACs but also offers a transformative platform for the sustainable synthesis of diverse single-atom electrocatalysts for clean energy and industrial applications.