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.

Electrocatalytic nitrogen reduction reaction (NRR) is a promising alternative to the traditional Haber–Bosch process. However, the sluggish kinetics and competitive hydrogen evolution reaction result in poor NH₃ yield and low Faradaic efficiency (FE). Herein, single bismuth atoms incorporated hollow titanium nitride nanorods encapsulated in nitrogen‐doped carbon layer (NC) supported on carbon cloth (NC/Bi SAs/TiN/CC) is constructed for electrocatalytic NRR. Impressively, as an integrated electrode, it exhibits a superior ammonia yield rate of 76.15 µg mg_cat⁻¹ h⁻¹ (9859 µg μmol_Bi⁻¹ h⁻¹) at −0.8 V versus RHE and a high FE of 24.60% at −0.5 V versus RHE in 0.1 m Na₂SO₄ solution, which can retain stable performance in 10 h continuous operation, surpassing the overwhelming majority of reported Bi‐based NRR catalysts. Coupling various characterizations with theory calculations, it is disclosed that the unique monolithic core‐shell configuration with porous structure endows abundant accessible active sites, outstanding charge‐transfer property, and good stability, while the cooperation effect of Bi SAs and TiN can simultaneously promote the hydrogenation of N₂ into NH₃* on the TiN surface and the desorption of NH₃^* to release NH₃ on the Bi SA sites. These features result in the significant promotion of NRR performance.

Preferential oxidation of CO (PROX) in a H₂-rich stream is considered as a promising strategy for abatement of trace amounts of CO to prevent poisoning of Pt anodes by H₂ in polymer–electrolyte membrane fuel cells (PEMFCs). The design of efficient catalysts is highly desirable to promote PROX. In this review, the recent advances in noble metal-based and non-noble metal-based catalysts for PROX are reviewed including some representative single-atom catalysts with outstanding catalytic performance. We summarize their synthetic methods, catalytic performance for PROX and reaction mechanisms with special emphasis on the synergistic effects between different components of catalysts that contribute to enhanced catalytic performance. Finally, the remaining challenges in PROX and some related promising strategies are indicated.