Ruthenium Engineered A_2B_2O_6-Hybrid Columbite Ferrite for Bifunctional pH-Universal Water Splitting

摘要

Single-atomic catalysts based on ruthenium have a balanced efficiency forwater splitting, but it is necessary to control their activity and durability. Inthis work, a binder-free Fe_(2-x)Ru_xNb_2O_6 (FRNO) hybrid catalyst is rationallydesigned through a facile hydrogel-crosslinking route. The as-prepared FRNOcatalyst exhibits high electrocatalytic activity and stability when operatingunder acidic (0.5 m H_2SO_4) and alkaline (1 m KOH) media. Operando X-rayadsorption and density functional theory calculations show that FRNO/CC, with its high intrinsic conductivity, promotes the adsorption and dissociationof water on its surface by regulating the charge distribution viacharge transfer to the coordinated surface oxygen. This facilitates the oxygenevolution reaction (OER) performance by stabilizing *OOH adsorption on Ruand Fe. The FRNO/carbon cloth (CC) hybrid catalyst also delivers excellentactivity and stability for both hydrogen evolution reaction (HER) and OERin pH-universal electrolytes with low overpotentials of 30 mV per 82 mV forHER and 200 mV per 260 mV for OER at a current density of 10 mA cm~(-2) inacidic/basic medium. Ultimately, the FRNO/CC hybrid catalyst shows goodwater-splitting performance, and it is expected to help contribute to the creationof various hybrid electrocatalysts.