The development of electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is crucial for sustainable energy and environmental initiatives. This work establishes an atomically-dispersed Ru-based model to investigate the promoting mechanism by the Ru-Integration effect in RuCo bimetallic nanoparticles supported on nitrogen-doped carbon (RuCo@NC). Specially, the Ru content in RuCo@NC plays a vital role for both HER and OER. The optimized catalyst shows an outstanding performance, requiring only 217 and 97 mV overpotential to reach a current density of 10 mA·cm⁻² for OER and HER respectively in alkaline conditions. Combined with advanced characterizations such as spherical aberration-corrected scanning transmission electron microscopy, X-ray absorption spectroscopy, in-situ Raman spectroscopy, and density functional theory calculations, it is found that Ru plays multiple crucial roles: (1) Ru restricts the growth of large Co NPs, while the small-sized Co NPs facilitate the formation of carbon nanotubes, which significantly enhances the mass/electron transfer; (2) Ru not only tunes the surface properties of Co but also acts as an active site for HER. As a result, when using RuCo@NC as an overall water splitting catalyst, it only needs a potential of 1.62 V to reach a current density of 100 mA·cm⁻². This work offers valuable insights into designing Ru-based electrocatalysts for water splitting.

Zinc-air batteries hold great promise as a next-generation efficient and environmentally friendly energy technology. However, the sluggish kinetics of the oxygen reduction reaction (ORR) process pose a significant challenge to their development. To address this issue, atom dispersion catalysts are developed to maximize the utilization of metal active centers. Metal-organic frameworks (MOFs) are a series of molecular materials with high atomic-level dispersion metal utilization, but they often lack sufficient electrical conductivity. Their application in MOF electrocatalysis remains limited unless the MOF material is transferred to a carbon-based material through heat treatment. To overcome this limitation, we employed coordination engineering to incorporate hexaaminotriphenylene (HATP) molecules with strong conjugation into Co-MOF-74. The resulting Co-MOF-74-HATP catalyst represents high activity, achieving an ORR half-wave potential (E_1/2) of 0.84 V and demonstrating good stability (ΔE_1/2 = 20 mV after 10,000 cycles). Additionally, the Co-MOF-74-HATP also performs a 320 mV overpotential (10 mA·cm⁻²) for the oxygen evolution reaction. Meanwhile, Co-MOF-74-HATP displays a peak power density of 96.6 mW·cm⁻² in zinc-air batteries, surpassing the commercially available Pt/C + RuO₂. This work presents a new pathway to design MOF-based ORR catalysts and provides a new direction for the preparation of key materials for zinc-air battery (ZAB).

Polyoxometalate-based nanocomposites with electrocatalytic activity have been applied in hydrogen evolution reactions (HER). Seawater as the main water resource on the earth should be developed as the water electrolysis to prepare high-purity hydrogen. In this paper, we used two synthesis strategies to prepare the nanocomposite Co₄-POM@Co-PGDY (Co₄-POM: the Kegging-type microcrystals of K₁₀[Co₄(PW₉O₃₄)₂] and Co-PGDY: cobalt-porphyrin linked graphdiyne) with excellent activity for HER. Co-PGDY as the porous material is applied not only as the protection of microcrystals towards the metal ion in seawater but also as the co-electrocatalyst of Co₄-POM. Co₄-POM@Co-PGDY exhibits excellent HER performance in seawater electrolytes with low overpotential and high stability at high density. Moreover, we have observed a key H₃O⁺ intermediate emergence on the surface of nanocomposite during hydrogen evolution process in seawater by Raman synchrotron radiation-based Fourier transform infrared (SR-FTIR). The results in this paper provide an effective strategy for preparing polyoxometalate-based electrocatalysts with high-performance toward hydrogen evolution reaction.