5f Covalency Synergistically Boosting Oxygen Evolution of UCoO₄ Catalyst

Abstract

Electronic structure modulation among multiple metal sites is key to the design of efficient catalysts. Most studies have focused on regulating 3d transition-metal active ions through other d-block metals, while few have utilized f-block metals. Herein, we report a new class of catalyst, namely, UCoO 4 with alternative CoO 6 and 5f-related UO 6 octahedra, as a unique example of a 5f-covalent compound that exhibits enhanced electrocatalytic oxygen evolution reaction (OER) activity because of the presence of the U 5f−O 2p−Co 3d network. UCoO 4 exhibits a low overpotential of 250 mV at 10 mA cm −2 , surpassing other unitary cobalt-based catalysts ever reported. X-ray absorption spectroscopy revealed that the Co 2+ ion in pristine UCoO 4 was converted to high-valence Co 3+/4+ , while U 6+ remained unchanged during the OER, indicating that only Co was the active site. Density functional theory calculations demonstrated that the OER activity of Co 3+/4+ was synergistically enhanced by the covalent bonding of U 6+ -5f in the U 5f−O 2p−Co 3d network. This study opens new avenues for the realization of electronic structure manipulation via unique 5f involvement.

Combined Corner‐Sharing and Edge‐Sharing Networks in Hybrid Nanocomposite with Unusual Lattice‐Oxygen Activation for Efficient Water Oxidation

“…As shown in Figure a, the XRD peaks of H‐SCF0.55 show almost no changes before and after OER, suggesting its stable crystal structure. [ 27,48 ] Additionally, the morphology of H‐SCF0.55 changes from long nanorods to short nanorods after sonication and after OER, which is ascribed to the necessary sonication step for sample preparation (Figure 2d; Figure S12, Supporting Information). According to the classical Scherrer formula, [ 49 ] the smaller particle size will lead to the larger integral half‐height width and thus a weaker XRD peak intensity, which is the origin of the reduced XRD peak intensity for H‐SCF0.55 after OER in Figure 5a.…”

Tremella-Like Ni–NiO with O-Vacancy Heterostructure Nanosheets Grown In Situ on MXenes for Highly Efficient Hydrogen and Oxygen Evolution

“…Over the past few years, transition-metal oxides (TMOs) have been extensively studied as potential OER catalysts due to their low cost, high activity, and tunable composition. They include binary Fe 2 O 3 , Co 3 O 4 , NiO, MoO 2 , and Cu 2 O and ternary Co 2 FeO 4 , NiCo 2 O 4 , NiMoO 4 , CoCr 2 O 4 , MnCo 2 O 4 , and UCoO 4 . Nevertheless, the catalytic HER activity of TMOs is poor due to their sluggish water dissociation kinetics.…”

“…They include binary Fe 2 O 3 , 10 Co 3 O 4 , 11 NiO, 12 MoO 2 , 13 and Cu 2 O 14 and ternary Co 2 FeO 4 , 15 NiCo 2 O 4 , 16 NiMoO 4 , 17 CoCr 2 O 4 , 18 MnCo 2 O 4 , 19 and UCoO 4 . 20 Nevertheless, the catalytic HER activity of TMOs is poor due to their sluggish water dissociation kinetics. Exploring earth-abundant bifunctional HER/OER electrocatalysts that can not only simplify the overall system but also reduce costs is extremely desirable for practical applications of water splitting but remains challenging.…”

Implanting an Electron Donor to Enlarge the d–p Hybridization of High‐Entropy (Oxy)hydroxide: A Novel Design to Boost Oxygen Evolution

“…Renewable energy technologies, therefore, have been drawing considerable attention and developed by leaps and bounds. [1][2][3] The oxygen evolution reaction (OER) is the fundamental process in several renewable energy technologies including water splitting, fuel cells, and metal-air batteries, and has been considered as a core issue in the production of green energy carriers, while OER is also the bottleneck due to its intrinsically sluggish four-electron transfer process. [4][5][6] In this regard, developing efficient electrocatalysts to boost OER kinetics is highly demanded.…”