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Coordination modulation of iridium single-atom catalyst maximizing water oxidation activity.

ABSTRACT: Single-atom catalysts (SACs) have attracted tremendous research interests in various energy-related fields because of their high activity, selectivity and 100% atom utilization. However, it is still a challenge to enhance the intrinsic and specific activity of SACs. Herein, we present an approach to fabricate a high surface distribution density of iridium (Ir) SAC on nickel-iron sulfide nanosheet arrays substrate (Ir₁/NFS), which delivers a high water oxidation activity. The Ir₁/NFS catalyst offers a low overpotential of ~170 mV at a current density of 10 mA cm^-2 and a high turnover frequency of 9.85 s^-1 at an overpotential of 300 mV in 1.0 M KOH solution. At the same time, the Ir₁/NFS catalyst exhibits a high stability performance, reaching a lifespan up to 350 hours at a current density of 100 mA cm^-2. First-principles calculations reveal that the electronic structures of Ir atoms are significantly regulated by the sulfide substrate, endowing an energetically favorable reaction pathway. This work represents a promising strategy to fabricate high surface distribution density single-atom catalysts with high activity and durability for electrochemical water splitting.

SUBMITTER: Lei Z

PROVIDER: S-EPMC8748886 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Origin of enhanced water oxidation activity in an iridium single atom anchored on NiFe oxyhydroxide catalyst.

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Dynamic chloride ion adsorption on single iridium atom boosts seawater oxidation catalysis.

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Project description:Tailoring the local chemistry environment to optimize the geometric and electronic properties of single atom catalysts has received much attention recently. Yet, most efforts have been devoted to establishing the preferable binding between the solid support and the single metal atom. In this work, a hybrid coordination environment was created for Fe-based single atom catalysts, comprising inorganic anchoring site from the support and organic ligands from the precursor. Using N,S co-doped graphene oxide as the support, Fe phthalocyanine was selectively anchored by the N/S sites, creating the unique N/S-Fe-N4 active sites as evidenced by extended X-ray absorption fine structure and Mössbauer spectrometry. Compared with other analogues with different metal centers or support, N/S-Fe-N4 showed much improved activity in oxygen reduction reaction, delivering onset and half-wave potentials of 1.02 and 0.94 V. This was superior over the state-of-the-art 20 wt % Pt/C and the classic Fe-N4 carbon catalysts. Density functional theory calculations revealed that the interaction between phthalocyanine ligands and heteroatom dopant from the support pushed electrons of Fe site to para-position, facilitating O2 adsorption and activation. This work shows the exciting opportunities of creating a hybrid coordination environment in single atom catalysts and paves a new avenue of improving their catalytic performance.

| S-EPMC9311226 | biostudies-literature

Iron atomic cluster supported on Co/NC having superior water oxidation activity over iron single atom.

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Ultrafast photodriven intramolecular electron transfer from an iridium-based water-oxidation catalyst to perylene diimide derivatives.

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| S-EPMC3465409 | biostudies-literature

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