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Abstract The interaction between metal nanoparticles (NPs) and their substrate plays a critical role in determining the particle morphology, distribution, and properties. The pronounced impact of a thin oxide coating on the dispersion of metal NPs on a carbon substrate is presented. Al₂O₃‐supported Pt NPs are compared to the direct synthesis of Pt NPs on bare carbon surfaces. Pt NPs with an average size of about 2 nm and a size distribution ranging between 0.5 nm and 4.0 nm are synthesized on the Al₂O₃coated carbon nanofiber, a significant improvement compared to those directly synthesized on a bare carbon surface. First‐principles modeling verifies the stronger adsorption of Pt clusters on Al₂O₃than on carbon, which attributes the formation of ultrafine Pt NPs. This strategy paves the way towards the rational design of NPs with enhanced dispersion and controlled particle size, which are promising in energy storage and electrocatalysis. 

Abstract Supported bimetallic alloy nanoparticles are of great interest in various catalytic applications due to the synergistic effects between different metals for improved catalytic performance. However, it still remains a challenge to efficiently synthesize atomically mixed alloy nanoparticles with uniform dispersion onto a desired substrate. Here, in situ, rapid synthesis of atomically mixed bimetallic nanoparticles well‐dispersed on a conductive carbon network via a 1 s high‐temperature pulse (HTP, ≈1550 K, duration 1 s, the rate of 10⁴K s⁻¹) is reported. The high temperature facilitates the total (atomic) mixing of different metals, while the rapid quenching ensures the uniform dispersion of nanoparticles with fine features such as twin boundaries and stacking faults, which are potentially beneficial to their catalytic performance. By varying the ratio of the precursor salts and parameters in the HTP process, the composition, size, and morphology of the resultant nanoparticles can easily be tuned. Moreover, the synthesized bimetallic (PdNi) nanoparticles demonstrate excellent electrocatalytic performance for the hydrogen evolution reaction and hydrogen peroxide electrooxidation. This work provides a general strategy for a facile and rapid synthesis of bimetallic nanoparticles directly from their salts for a range of emerging applications.