A 3D self-supported integrated electrode, consisting of heteroatomic nitrogen-doped carbon nanotube arrays on carbon cloth with confined ultrafine Co₄N nanoparticles and a distribution of anchored single-atom Co, is fabricated via a cobalt-catalyzed growth strategy using dicyandiamide as the nitrogen and carbon source and a layered cobalt hydroxide-nitrate salt as the precursor. The abundance of exposed active sites, namely, the Co₄N nanoparticles, single-atom Co, and heteroatomic N-doped carbon nanotubes, and multiple synergistic effects among these components provide suitable tailoring of thed-band center for facilitating vectorial electron transfer and efficient electrocatalysis. Benefiting from the merits of its structural features and electronic configuration, the prepared electrode exhibits robust performance toward the hydrogen evolution reaction with overpotentials of only 78 and 86 mV at 10 mA cm⁻²in acidic and basic electrolytes, respectively. Density functional theory calculations and X-ray photoelectron spectroscopy valence band measurements reveal that the effective tailoring of thed-band center by Co₄N nanoparticles plays a crucial role in optimizing the hydrogen adsorption free energy to a more thermoneutral value for efficient electrocatalysis.

Novel hollow mesoporous @M/CeO₂ (M = Au, Pd, and Au–Pd) nanospheres are created. The nanospheres can be used as effective nanoreactors with superior catalytic activity and stability for reduction of 4-nitrophenol due to their hollow mesoporous structural features.

Catalyzed reduction of 4-nitrophenol with NaBH₄ and oxidation of methanol, the Fe₃O₄@CeO₂/M (M = Pt and Pd) dual-heterostructural catalysts manifest superior catalytic efficiency and electrocatalytic reactivity and reusability.