Co−Co Dinuclear Active Sites Dispersed on Zirconium‐doped Heterostructured Co₉S₈/Co₃O₄ for High‐current‐density and Durable Acidic Oxygen Evolution

Abstract

Developing cost‐effective and sustainable acidic water oxidation catalysts requires significant advances in material design and in‐depth mechanism understanding for proton exchange membrane water electrolysis. Herein, we developed a single atom regulatory strategy to construct Co‐Co dinuclear active sites (DASs) catalysts that atomically dispersed zirconium doped Co9S8/Co3O4 heterostructure. The X‐ray absorption fine structure elucidated the incorporation of Zr greatly facilitated the generation of Co‐Co DASs layer with stretching of cobalt oxygen bond and S‐Co‐O heterogeneous grain boundaries interfaces, engineering attractive activity of significantly reduced overpotential of 75 mV at 10 mA cm−2, a breakthrough of 500 mA cm−2 high current density, and water splitting stability of 500 hours in acid, making it one of the best‐performing acid‐stable OER non‐noble metal materials. The optimized catalyst with interatomic Co‐Co distance (ca. 2.80 Å) followed oxo–oxo coupling mechanism that involved obvious oxygen bridges on dinuclear Co sites (1,090 cm–1), confirmed by in situ SR‐FTIR, XAFS and theoretical simulations. Furthermore, a major breakthrough of 120,000 mA g–1 high mass current density using the first reported noble metal‐free cobalt anode catalyst of Co‐Co DASs/ZCC in PEM‐WE at 2.14 V was recorded.

Mapping current high-entropy materials for water electrolysis: from noble metal to transition metal

“…The direct oxo–oxo coupling mechanism (DOOC) can be achieved in dinuclear active-site catalysts, for instance, dinuclear Co–Co sites in Co 9 S 8 /Co 3 O 4 . 61 O–O coupling occurs at the heterointerface between Au clusters and NiFe-hydroxide, which is denoted as interfacial DOOC. 62 Very recently, Ru atoms embedded into cation vacancies of the Co 3 O 4 surface can switch the reaction pathway from LOM to optimized AEM by activating the proton donor–acceptor mechanism (PDAM), elucidating the acidic oxygen evolution.…”

State-of-the-Art In Situ Technologies for Unravelling the Dynamic Structure Evolution during Acidic Oxygen Evolution Reaction

“…Thus, the AEM pathway could be further classified into the new type AEM which occurred over synergistic sites to break the scaling relationships and the classic type at a single site with limited performance (Figure 3c). 38 Besides the peaks attributed to *OOH/*OO, other intermediates such as M�O and *O have been monitored via SR-FTIR to analyze the specific process of the OER. For oxygen species adsorbed over Ir-based catalysts, the adsorption peak of the O−O species was always located between 700 and 900 cm −1 , while M�O tended to be observed between 800 and 1000 cm −1 .…”

“…By comparing the stretching vibration of *OOH, the peak of 1090 cm –1 could be attributed to the O–O bond formed at dual Co–Co sites (Figure b), while the peak of 1024 cm –1 was considered the Co–*OOH intermediates. Thus, the AEM pathway could be further classified into the new type AEM which occurred over synergistic sites to break the scaling relationships and the classic type at a single site with limited performance (Figure c) …”

Atomic-Level Asymmetric Tuning of the Co1–N3P1 Catalyst for Highly Efficient N-Alkylation of Amines with Alcohols

“…Typically, the metal center in SACs is stabilized and regulated by the coordination of the heteroatom (N, S, O, P, etc.) in the support matrix. − The direct pyrolysis of metal-zeolite imidazolate frameworks (M-ZIFs) is currently believed to be a significant method for the preparation of metal–nitrogen-carbon SACs (M/NC-SACs) with the symmetric coordination of N atoms. − It is noteworthy that compared with symmetrical M-NC, asymmetric M-NPC constructed by doping P atoms with a weaker electronegativity than N atoms can further modulate the electronic structure of the metal center and improve its catalytic efficiency. For example, our recent study has demonstrated that the superior peroxidase-like activity of FeN 3 P-SAzyme was attributed to the electron-donating P atoms, which reduced the positive charge of the metal Fe center .…”