Neodymium‐Evoked Valence Electronic Modulation to Balance Reversible Oxygen Electrocatalysis

Abstract

Suffering from the competition adsorption between oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), the development of high‐efficiency oxygen electrocatalysts with bifunctional properties still remains a challenge. Herein, a novel and effective neodymium‐evoked valence electronic perturbation strategy to improve and balance reversible oxygen electrocatalysis of metallic cobalt sites is proposed. To heighten the coupling between Nd and Co, the metal‐organic‐framework‐induced method is chosen to prepare the target catalyst of atomic Nd‐doped Co on an N‐doped carbon substrate. The as‐prepared catalyst presents excellent bifunctional electrocatalytic properties with a low overpotential of 288 mV at 10 mA cm−2 for the OER and a high half‐wave potential of 0.85 V for the ORR. The robust electrocatalytic stabilities for both the ORR and OER are also proven. The electrochemical in situ Raman spectra confirm the surface dynamic change of the transformation of oxygen intermediates by noting the formation of Co–OOH. Theoretical calculations verify that the adsorption of oxygen intermediates is balanced owing to the strong Co 3d‐Nd 4f orbital electronic coupling effect below the Fermi level. Moreover, the potential practicability of catalyst is further demonstrated in solid‐state rechargeable Zn‐Air batteries, which exhibit large power density and a long cycling life.

Heterointerface and Tensile Strain Effects Synergistically Enhances Overall Water‐Splitting in Ru/RuO2 Aerogels

“…Based on the Sabatier principle, an excellent HER electrocatalyst shows hydrogen adsorption free energy (ΔG H *) near zero. [68,69] The HER Gibbs free energy graph shows that the ΔG H * of Ru/RuO 2 (−0.22 eV) is closer to ideal (ΔG H * = 0 eV) in contrast with Ru (−0.54 eV) and RuO 2 (−0.26 eV) (Figure 6e), which demonstrates the exceptional HER electrocatalytic performance of Ru/RuO 2 .…”

Controlled synthesis of Crx–FeCo2P nanoarrays on nickel foam for overall urea splitting

“…Among them, the OER involves a complex process of four electrons and four protons, which leads to slow kinetics and exhibits high potentials, thus making it as a rate-determining step in water splitting and greatly limiting the efficiency of hydrogen production. 7–12 Therefore, by replacing the OER reaction of high theoretical potential (1.23 V vs. RHE) with a reaction of low theoretical potential, the energy consumption during the reaction can be reduced. 13–16 In contrast, the urea oxidation reaction (UOR) demands only a low theoretical potential of 0.37 V ( vs. RHE), which, together with its non-toxic, low-cost, easy storage and the ability to purify wastewater, allows urea splitting to replace water splitting and thus achieve hydrogen economy.…”

Cross-Linked Double-Active Centers for Efficient pH-Universal Oxygen Reduction Catalysis

“…In recent years, zinc–air batteries (ZABs) are one of the most promising clean energy conversion and storage devices on account of their advantages of high theoretical energy density (1086 W h kg –1 ), low cost, high safety, and environmental friendliness. − However, the slow electron transfer kinetics of the oxygen reduction reaction (ORR) during cathode discharge limits the overall reaction rate and battery durability. , At present, a platinum (Pt)-based catalyst is considered the best catalyst for ORR. Unfortunately, the disadvantages of high cost and low natural abundance hinder its further application in energy conversion devices.…”