Ir/Ni–NiO/CNT composites as effective electrocatalysts for hydrogen oxidation

Ji, Xiafang; Chen, Peng; Liu, Yuanjun; Ji, Zhenyuan; Zhou, Hongbo; Chen, Caiyao; Shen, Xiaoping; Fu, Xiaoqi; Zhu, Guoxing

doi:10.1039/d2ta07417f

Cited by 12 publications

(15 citation statements)

References 49 publications

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“…As shown by the plots of the RDS free energy relationship with Δ G *H and Δ G *OH (Figure d), the moderately enhanced adsorptions of both *H and *OH derived from the ensemble effects of pairwise Pt 2 -on-Rh coordination sites are pivotal for attaining the lowest RDS free energy, which ensure a certain coverage of *H and then promote the combination of *H and *OH to export drastically increased alkaline HOR activity. This discovery upgrades the previous mainstream research idea that mainly focuses on tuning the *H adsorption strength approaching 0 eV in both the HBE and OHBE theories. , On the basis of the foregoing analysis, it is reasonable to believe that the HOR in alkaline conditions can be substantially enhanced on low-dimensional bimetallic surfaces that can simultaneously provide active sites for coincidentally enhancing the dissociative adsorption of H 2 and the adsorption of reactive *OH . In this case, the synergy not only takes place between two identical Pt atoms but also happens between dual-Pt and adjacent Rh ensemble atomic sites.…”

Section: Resultsmentioning

confidence: 78%

Host–Guest Ensemble Effect on Dual-Pt atom-on-Rh Nanosheets Enables High-Efficiency and Anti-CO Alkaline Hydrogen Oxidation

et al. 2023

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Explicit atomic coordinations of binary metal atoms on low-dimensional host–guest-type bimetallic nanomaterials can arouse unique ensemble effects and significantly improve the catalysis performances, but they confront a formidable challenge in chemical synthesis. Here, we draw on a thermoinduced secondary crystallization process of preprepared amorphous/crystalline hybrid ultrathin Rh nanosheets (NSs) to capture Pt atoms into the two-dimensional (2D) Rh lattice, by which precisely controlled Pt atomic dispersions from a single atom to dual atoms and to clustered atoms can be facilely elected and embedded into the ultrathin Rh hosts. Among them, the dual-Pt atom-on-Rh (denoted as Pt2–Rh) NSs exhibit an extremely high activity and an excellent CO tolerance for the alkaline hydrogen oxidation reaction (HOR), achieving a 18.5 times higher mass activity at 50 mV overpotential than that of commercial Pt/C. Theoretical studies indicate that the host–guest ensemble effect aroused by the specific pairwise Pt2-on-Rh coordination feature can moderately enhance both the surface *H and *OH bindings, which synergistically lower the free energy of the rate-determining Volmer step and thus promote the combination of neighboring *H and *OH to form H2O. Enhanced *H adsorption can also prevent the main available sites from being occupied by hydroxyl groups in alkaline conditions. The free energy diagram and anti-CO experiments coherently indicate that the oxidation of *CO by neighboring *OH to form *COOH is kinetically more favorable to proceed on the Pt2–Rh NSs, effectively preventing the catalysts from being poisoned. This work sheds light on the ensemble effect of host–guest heteroatom coordinations for designing high-efficiency alkaline HOR catalysts.

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Section: Resultsmentioning

confidence: 78%

Host–Guest Ensemble Effect on Dual-Pt atom-on-Rh Nanosheets Enables High-Efficiency and Anti-CO Alkaline Hydrogen Oxidation

et al. 2023

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“…2(d) and Table S2 (ESI†) summarize and compare the two mass-specific values of different precious metal based HOR electrocatalysts reported in the literature as well as the commercial benchmark catalysts. 12,14,23–36 Remarkably, the j k,m value of our Ni@IrNi is about four-fold greater than those of 20 wt% Ir/C and 20 wt% Pt/C, and significantly exceeds that of 20 wt% PtRu/C; its j 0,m value is about twice greater than those of 20 wt% Ir/C and 20 wt% Pt/C as well as 20 wt% PtRu/C (Fig. S13, ESI†).…”

Section: Resultsmentioning

confidence: 89%

“…the literature as well as the commercial benchmark catalysts. 12,14,[23][24][25][26][27][28][29][30][31][32][33][34][35][36] Remarkably, the j k,m value of our Ni@IrNi is about four-fold greater than those of 20 wt% Ir/C and 20 wt% Pt/C, and significantly exceeds that of 20 wt% PtRu/C; its j 0,m value is about twice greater than those of 20 wt% Ir/C and 20 wt% Pt/C as well as 20 wt% PtRu/C (Fig. S13, ESI †).…”

Section: Energy and Environmental Science Papermentioning

confidence: 99%

Prominent electronic effect in iridium-alloy-skinned nickel nanoparticles boosts alkaline hydrogen electrocatalysis

Xu,

Wang,

Mao

et al. 2023

Energy Environ. Sci.

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“…Ir 2 Ni 8 /NHCSs [78] 10 / 0.246 / IrNi@Ir/C [37] 10 1.22 / 1.12 IrNi@PdIr/C [36] 19.7 0.209 / 0.854 Ir/Ni-NiO/CNT [79] 29.46 2.04 / 1.59…”

Section: Discussionmentioning

confidence: 99%

Recent Advances in Platinum Group Metal Based Alloys for Alkaline Hydrogen Oxidation Reaction

Ma,

Zhang,

Zhou

et al. 2023

ChemNanoMat

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The development of efficient electrocatalysts for alkaline hydrogen oxidation reaction (HOR) is crucial to realize the commercialized application of alkaline exchange membrane fuel cells. Platinum group metals (PGMs) have been extensively used as alkaline HOR catalysts because they exhibit high activity and stability. Currently, searching for methods to improve the catalytic activity and reduce the loading of PGMs is the main research interest of PGM‐based electrocatalysts. The alloying method has been regarded as an effective strategy. In this review, we summarized various kinds of PGM‐based alloys, including traditional random alloys, single‐atom alloys, high‐entropy alloys and intermetallic compounds, and highlighted the challenges and future directions regarding the development of advanced PGM‐based alloys.

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Ir/Ni–NiO/CNT composites as effective electrocatalysts for hydrogen oxidation

Abstract: Developing highly efficient non-Pt hydrogen oxidation (HOR) catalysts used in alkaline solution is very important for anion exchange membrane hydrogen-oxygen fuel cells. Herein, Ir/Ni-NiO/CNT composite catalysts were designed and prepared,...

Cited by 12 publications

References 49 publications

Host–Guest Ensemble Effect on Dual-Pt atom-on-Rh Nanosheets Enables High-Efficiency and Anti-CO Alkaline Hydrogen Oxidation

Host–Guest Ensemble Effect on Dual-Pt atom-on-Rh Nanosheets Enables High-Efficiency and Anti-CO Alkaline Hydrogen Oxidation

Prominent electronic effect in iridium-alloy-skinned nickel nanoparticles boosts alkaline hydrogen electrocatalysis

Recent Advances in Platinum Group Metal Based Alloys for Alkaline Hydrogen Oxidation Reaction

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