Ru/Rh Cation Doping and Oxygen‐Vacancy Engineering of FeOOH Nanoarrays@Ti₃C₂T_x MXene Heterojunction for Highly Efficient and Stable Electrocatalytic Oxygen Evolution

Abstract

Oxyhydroxides hold promise as highly-efficient non-noble electrocatalysts for the oxygen evolution reaction (OER), but their poor conductivity and structural instability greatly impede their progress. Herein, the authors develop a cation-doping and oxygenvacancy engineering strategy to fabricate Ru/Rh-doped FeOOH nanoarrays with abundant oxygen-vacancies in situ grown on Ti 3 C 2 T x MXene (Ru/Rh-FeOOH@Ti 3 C 2 T x ) as highly-efficient OER electrocatalysts. Benefiting from Ru/Rh-cation regulation, oxygenvacancy engineering, and heterojunction synergy between MXene and modulated FeOOH, the optimized Rh/Ru-FeOOH@Ti 3 C 2 T x electrocatalysts exhibit excellent OER activities and remarkable stabilities with 100 h. Particularly, 3%Rh-FeOOH@Ti 3 C 2 T x electrocatalyst only needs a 223 mV overpotential at 10 mA cm -2 and 306 mV to reach 100 mA cm -2 , which is superior to commercial IrO 2 catalyst and most reported oxyhydroxide-based electrocatalysts. Further, systematically theoretical caculation, kinetics, thermodynamics, and microstructural analysis verify that the integration of Ru/Rh-cation doping and oxygen vacancy obviously enhances the intrinsic conductivity and lattice defects of FeOOH and expose more active sites, thereby decreasing the adsorption/desorption energy barrier and activation energy, and improving the specific activity and catalytic kinetics of electrocatalysts, whereas in situ hybridization with MXene strengthens the structural stability. This work clearly confirms that cationdoping and oxygen-vacancy engineering offers a joint strategy for the electronic structure modulation and design of highlyefficient inexpensive OER electrocatalysts.Research data are not shared.

In situ construction of 3D low-coordinated bismuth nanosheets@Cu nanowire core–shell nanoarchitectures for superior CO2 electroreduction activity

“…32 The abundant defects may provide more active sites, thus being favorable for boosting the charge transfer and improving the catalytic activity of the catalyst. 15,33–36 XPS was conducted to further probe the surface elemental composition and chemical bonding states of the reduced Bi catalyst. Two obvious peaks positioned at 159 eV and 164.3 eV are shown in the high-resolution XPS spectrum of Bi 4f in Fig.…”

Plasma-Induced Surface Reconstruction of NiFe/Co3O4 Nanoarrays for High-Current and Ultrastable Oxygen Evolution and the Urea Oxidation Reaction

“…The significant increment in the O v concentration after the i−t test demonstrates the formation of defect sites and dangling bonds, which can exhibit excellent electrocatalytic activity for the OER. 53,54 In general, XPS results show that the surface modification may due to the chemical reduction of the plasma, and the amorphous trimetal structure may further favor the electrochemical surface reconstruction to generate active sites during the OER process. 44,55 In addition, the Ni and Fe elements are well preserved even after the 240 h i−t test at 1 A cm −2 (Table S2), further illustrating their good structural stability.…”

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