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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. 

For the first time, a fast heating–cooling process is reported for the synthesis of carbon‐coated nickel (Ni) nanoparticles on a reduced graphene oxide (RGO) matrix (nano‐Ni@C/RGO) as a high‐performance H₂O₂fuel catalyst. The Joule heating temperature can reach up to ≈2400 K and the heating time can be less than 0.1 s. Ni microparticles with an average diameter of 2 µm can be directly converted into nanoparticles with an average diameter of 75 nm. The Ni nanoparticles embedded in RGO are evaluated for electro‐oxidation performance as a H₂O₂fuel in a direct peroxide–peroxide fuel cell, which exhibits an electro‐oxidation current density of 602 mA cm⁻²at 0.2 V (vs Ag/AgCl), ≈150 times higher than the original Ni microparticles embedded in the RGO matrix (micro‐Ni/RGO). The high‐temperature, fast Joule heating process also leads to a 4–5 nm conformal carbon coating on the surface of the Ni nanoparticles, which anchors them to the RGO nanosheets and leads to an excellent catalytic stability. The newly developed nano‐Ni@C/RGO composites by Joule heating hold great promise for a range of emerging energy applications, including the advanced anode materials of fuel cells.