Nickel-based catalysts have been good candidates for steam reforming of methane, but their stability has been restricted due to the agglomeration among particles at high temperature. In the present work, a new type of Ni@SiO₂ yolk-shell nanoreactor framework comprising Ni cores inside hollow silica shells has been prepared through direct silica coating and subsequent selective etching of the metal cores. This nanoreactor framework is remarkably stable at high temperatures up to 973 K, because the silica hollow shells around the nickel cores essentially block particle sintering. The Ni@SiO₂ nanoreactor structure is employed as a model catalyst for the steam methane reforming reaction. The catalysts exhibit a continuous conversion rate of methane and hydrogen, and significantly enhanced stability at high temperatures, leading to high recyclability without loss of catalytic activity. These reaction properties are superior to Ni/MCF catalysts, and comparable with state-of-the-art commercial catalysts. This catalyst design can be generalized for other bifunctional systems, such as Co@SiO₂ and Fe@SiO₂.

PdCu bimetallic nanoparticles (NPs) having mixed disordered face-centered cubic (fcc) and ordered body-centered cubic (B2-type) phases enhance the kinetics of oxygen reduction/evolution reaction by significant reduction of overpotentials, which leads to the superb round-trip efficiency of ∼80%. In addition, the PdCu catalyst demonstrates a remarkable cyclic enhancement in stability and an outstanding rate capability even at a high current density of 5000 mA g_carbon ⁻¹. Our first-principles calculations demonstrate that the low overpotentials of the PdCu catalyst are strongly correlated with the weak LiO₂ adsorption strength, caused by electron transfer from Cu to the top-layer Pd atoms on the surface.