Nanoparticles supported on carbonaceous substrates are promising electrocatalysts. However, achieving good stability for the electrocatalysts during long-term operations while maintaining high activity remains a grand challenge. Herein, a highly stable and active electrocatalyst featuring high-entropy oxide (HEO) nanoparticles uniformly dispersed on commercial carbon black is reported, which is synthesized via rapid high-temperature heating (≈1 s, 1400 K). Notably, the HEO nanoparticles with a record-high entropy are composed of ten metal elements (i.e., Hf, Zr, La, V, Ce, Ti, Nd, Gd, Y, and Pd). The rapid high-temperature synthesis can tailor structural stability and avoid nanoparticle detachment or agglomeration. Meanwhile, the high-entropy design can enhance chemical stability to prevent elemental segregation. Using oxygen reduction reaction as a model, the 10-element HEO exhibits good activity and greatly enhances stability (i.e., 92% and 86% retention after 12 and 100 h, respectively) compared to the commercial Pd/C electrocatalyst (i.e., 76% retention after 12 h). This superior performance is attributed to the high-entropy compositional design and synthetic approach, which offers an entropy stabilization effect and strong interfacial bonding between the nanoparticles and carbon substrate. The approach promises a viable route toward synthesizing carbon-supported high-entropy electrocatalysts with good stability and high activity for various applications.

Herein, we develop a transient heating-quenching strategy triggered by Joule heating for the synthesis of single-atom cobalt- and nitrogen-doped graphene materials with three-dimensional porous monolithic architecture (denoted as CoNG-JH). The ultrafast Joule heating procedure simultaneously enables the reduction of graphene oxide and the incorporation of metal and nitrogen atoms into the graphene matrix within 2-second period. Meanwhile, the transient quenching avoids the extended heating-induced atom aggregation, ensuring the rapid and stable dispersion of atomic-scale CoNx active sites in graphene. Additionally, the interconnected macropores and nanopores formed by the self-assembly of graphene sheets facilitate the unimpeded ion and gas transport during the catalytic process. When used as an electrode for the hydrogen evolution reaction (HER), the fabricated freestanding CoNG-JH exhibits high catalytic activity and durability with a low overpotential of 106 mV at 10 mA·cm−2 and a small Tafel slope of 66 mV·dec−1 in 0.5 M H2SO4 electrolyte. The presented synthesis and design strategy open up a rapid and facile route for the manufacturing of single atom catalysts.

High-entropy materials (HEMs) have garnered tremendous attention for electrocatalytic water oxidation because of their extraordinary properties. Nevertheless, scant attention has been directed toward comprehending the origin of their excellent activity and intricate atomic arrangements. Herein, we demonstrate the synthesis of high-entropy metal selenides (HEMSs) using a rapid joule-heating method, effectively circumventing the immiscibility challenges inherent in combining multiple metal elements. This achievement is collectively verified by a convergence of diverse analytical techniques encompassing quasi in situ X-ray absorption spectroscopy and operando attenuated total reflectance infrared spectroscopy. The HEMS exhibits a low overpotential of 222 mV at 10 mA cm−2 and extraordinary durability with negligible degradation over a 1,000 h durability test at 10 mA cm−2 and 500 h at 100 mA cm−2. Further, our theoretical investigations establish the pronounced mechanism of asymmetric Cu-Co-Ni active units in HEMS by manipulating the interaction of oxygen-containing intermediates, which leads to enhanced OER activity and durability.