CeO₂ Functionalized Cobalt Layered Double Hydroxide for Efficient Catalytic Oxygen‐Evolving Reaction

Abstract

Water splitting to produce hydrogen is an effective means to alleviate the energy crisis. The anodic oxygen‐evolving reaction (OER) limits the overall efficiency due to its high energy barrier. To address this, layered double hydroxides (LDHs) with high catalytic activities have been widely studied, especially those modified with CeO2, either bound to the surface or doped into interior. However, experimental evidence for the atomic‐level understanding of the mechanism for the enhanced catalytic performance is conspicuously missing. Herein, anchoring CeO2 nanoparticles onto Co LDH, based on the thoughts of loading capacity and size effect to regulate the properties of the interface and to optimize the performance, is attempted. The electronic interactions are studied by X‐ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy (EELS), revealing electron transfer from Co2+ to Ce4+ that leads to an increase in Co3+. The strong Lewis acidity of Co3+ helps the binding of OH−, which is conducive to the formation and transformation of oxygen‐containing intermediates. Providing evidence is the formation of one of the key intermediates Co‐OOH at a sizably reduced potential as monitored by in situ Raman spectroscopy. With this work, the atomic level correlation of site‐specific electronic interactions with the enhanced catalytic performance is clearly established.

Perovskites with Enriched Oxygen Vacancies as a Family of Electrocatalysts for Efficient Nitrate Reduction to Ammonia

“…Deconvolution of Co 2p 3/2 and Co 2p 1/2 peaks confirm the existence of Co 3+ and Co 2+ species in LaCoO 3 (Figure 2e). [42] The La 3d spectra of LaCrO 3 , LaMnO 3 , LaFeO 3 and LaCoO 3 all show a pair of spin orbital peaks at 834.1 and 850.5 eV, respectively (Figure S6, Supporting Information). [33] These results are consistent with the previously reported studies, verifying the successful preparation of LaCrO 3 , LaMnO 3 , LaFeO 3 , and LaCoO 3 perovskites.…”

“X-Scheme” Charge Separation Induced by Asymmetrical Localized Electronic Band Structures at the Ceria Oxide Facet Junction

“…As reported, the Ce species in CeO 2 includes two convertible oxidation states: Ce 4+ and Ce 3+ , which are often accompanied by the formation of oxygen vacancies. 20 As shown in Figure S3, the crystal structure of the (111)/ (100)CeO 2−x photocatalyst is not destroyed under the reduction treatment. The electron energy loss spectrum (EELS) of (111)/(100)CeO 2−x in Figure S4 also proves the coexistence of Ce 3+ and Ce 4+ .…”

Recent advances and perspectives of CeO2-based catalysts: Electronic properties and applications for energy storage and conversion

“…Similarly, CeO 2 (110) presents the highest possibility for FLPs construction ( Huang, 2016 ; Zhang et al, 2017 ). Many studies have proposed that FLPs constructed on defective ceria possess high activities for many small-molecule activation (such as, H 2 , NO, CO 2 ) ( Mo et al, 2015 ; Stephan and Erker, 2015 ; Huang et al, 2018 ; Li J. et al, 2021 ; Li et al, 2022 ; Zhang et al, 2022 ; Zou et al, 2022 ). Qu’s group have explored the adsorption and activation of CO 2 on CeO 2 (110) surface by DFT calculations and found that CO 2 can be easily activated on defective CeO 2 and further activated on FLPs because of the more negatively charged oxygen of CO 2 , when compared to CO 2 on an ideal CeO 2 (110) surface ( Figure 6A ) ( Zhang et al, 2019 ).…”

“…Meanwhile, CeO 2 /Co 3 O 4 interface nanotubes with a Ce/Co ration of 2:20 can achieve an ultrahigh mass activity with a current density of 128.6 A·g −1 at a given overpotential of 340 mV and enable an OER Faradaic efficiency of ∼99%. Li et al (2022) have reported a very different conclusion on the valence of active Co ions by using CeO 2 nanoparticles anchored Co layered double hydroxide (LDH) as a catalyst. They deemed that the Co 3+ with strong Lewis acidity helps the binding of OH − and thus benefiting the formation and transformation of oxygen-containing intermediates by forming CoOOH active species ( Li Z. et al, 2021 ).…”