V–O Species-Doped Carbon Frameworks Loaded with Ru Nanoparticles as Highly Efficient and CO-Tolerant Catalysts for Alkaline Hydrogen Oxidation

Dilute RuCo Alloy Synergizing Single Ru and Co Atoms as Efficient and CO‐Resistant Anode Catalyst for Anion Exchange Membrane Fuel Cells

“…[8a] Figure S10a shows the O 1s spectrum in (RuCo) NC + SAs /N-CNT, with three peaks assigned to MÀ O (M = Ru or Co), C=O, and O=C-O at 529.9, 531.7, and 533.8 eV, respectively. [16] In addition, the N 1s spectrum in Figure S10b corresponds to pyridine N, metal N, and graphite N at 398.7, 399.9, and 401.9 eV, respectively. [17] The atomic-level structure of (RuCo) NC + SAs /N-CNT was further characterized by X-ray absorption fine structure (XAFS) spectroscopy technology.…”

“…This is consistent with the results of the CO stripping experiment, which indicates the strength of OH adsorption. [25] As shown in Figure 5c, the CO stripping peak potential of (RuCo) NC + SAs /N-CNT is lower than that of Ru NC + SA /N-CNT, indicating that the OH adsorption on active sites in (RuCo) NC + SAs /N-CNT is stronger than that of Ru NC + SA /N-CNT, which can promote the Volmer step, accelerate the alkaline HOR, and facilitate the removal of *CO, improving the ability to resist CO. [16] The changing of *CO oxidation's free energy was calculated to estimate the capacity to resist CO poisoning during HOR, including *CO adsorption and consecutive oxidization into *COOH and CO 2 species (Figure 5d). CO molecules are highly adsorbed on the surfaces of Ru(001) (À 1.61 eV) and RuCo NC (À 1.32 eV).…”

Hydrogen oxidation electrocatalysts for anion-exchange membrane fuel cells: activity descriptors, stability regulation, and perspectives

“…Similarly, Chen et al presented a robust Ru-based catalyst (Ru/VOC) comprising ultrasmall Ru nanoparticles supported on carbon frameworks with atomically dispersed V–O species. 376 This catalyst demonstrates superior HOR activity and stability, coupled with exceptional CO tolerance. Experimental findings, alongside DFT calculations, reveal that the V–O species serve as ideal sites for OH − adsorption, enabling Ru to free up additional sites for hydrogen adsorption.…”

Balancing the Binding of Intermediates Enhances Alkaline Hydrogen Oxidation on D-Band Center Modulated Pd Sites

“…It is essential to comprehend the overall mechanism of the HOR in alkaline environments in order to develop a precise approach for creating efficient catalysts for the HOR. − The mechanistic sequence of the elementary steps for the HOR is generally accepted to start with the adsorption of H 2 and its subsequent transformation to a surface-adsorbed H-adatom (H ads ) by either the Tafel (H 2 → 2H ads ) or Heyrovsky step (H 2 + OH – → H 2 O + H ads + e – ), followed by the Volmer step (H ads + OH – → H 2 O + e – ). − According to Markovic et al’s well-known bifunctional mechanism, additional incorporation of OH – adsorption in the Volmer step is often regarded to be the step that determines the rate of alkaline HOR by engaging in competition with H ads to decrease the number of available active sites. , That is, the facilitation of HOR kinetics is significantly influenced by the adsorption of both hydrogen and OH – . − In particular, some mechanistic studies have specifically examined the attachment of water molecules (Δ G 0 H2O* ) at the interface on catalyst surfaces that is strongly linked to HOR catalytic rates. − Despite the widespread recognition of water’s impact on reactants and intermediates, there is still a need for further investigation into the role of water as the product of the Volmer step. Besides the well-known Pt, Pd displays similar properties but has more abundant natural reserves in comparison to Pt, optimal values of *H binding energy (HBE), and thus has been considered a potential contender for HOR to substitute expensive Pt in order to decrease the cost of catalysts. − Therefore, it is evident that simultaneous rational and precise engineering of the surface of Pd-based catalysts and understanding the detailed mechanism of interfacial water molecules on the surface of catalysts are crucial for enhancing the activity and longevity of electrocatalysts for HOR in alkaline environments; however, these continue to present difficulties.…”