Kinetically favorable edge-type iron–cobalt atomic pair sites synthesized via a silica xerogel approach for efficient bifunctional oxygen electrocatalysis

Abstract

Efficient fabrication of bimetallic single-atom catalysts (SACs), holding bi-activity to accelerate both electrochemical oxygen reduction (ORR) and evolution reaction (OER), is highly desired for advanced battery devices. The chemical environment...

Carbon-Layer-Protected CoP/Carbon Nanosheets as Highly Durable Bifunctional Electrocatalysts for Rechargeable Zinc–Air Batteries

“…The X-ray diffraction (XRD) pattern of the CoP@C/CNSs displayed in Figure a shows distinct diffractions at 31.8°, 36.5°, 46.2°, 48.3°, 52.4°, and 56.8°, respectively assigned to the (011), (111), (112), (211), (103), and (301) facets of CoP (JCPDS 29-0497), further confirming the formation of CoP crystals. The Raman spectrum offers the details of the chemical composition and geometric defect, which can affect the electrocatalytic performance of OER and ORR . As shown in Figure b, the deconvoluted Raman spectrum of the CoP@C/CNSs features two distinct peaks at ∼1350 and ∼1590 cm –1 for the D and G bands, respectively.…”

“…The Raman spectrum offers the details of the chemical composition and geometric defect, which can affect the electrocatalytic performance of OER and ORR. 28 As shown in Figure 2b, the deconvoluted Raman spectrum of the CoP@ C/CNSs features two distinct peaks at ∼1350 and ∼1590 cm −1 for the D and G bands, respectively. The band intensity ratio, i.e., I D /I G , was calculated to be ∼0.997, suggesting the abundance of graphitic C in CoP@C/CNSs.…”

Molecular design and coordination regulation of atomically dispersed bi-functional catalysts for oxygen electrocatalysis

“…The mechanism of the ORR has been widely studied by experimental and computational methods. Generally, the ORR involves a four-proton electron pathway for the electrochemical reduction of molecular oxygen (O 2 ) to water (H 2 O) (eqn (1)), or a two-proton electron transfer for production of hydrogen peroxide (H 2 O 2 ) (eqn (2)). The direct four-electron mechanism that can ensure an ideal efficiency is desirable for energy conversion devices such as metal-air batteries and fuel cells, so we discuss it in the following parts.…”

“…Novel secondary batteries as promising alternatives to fossil energy, including metal-air batteries, metal-CO 2 batteries, and metal-sulfur batteries, perform reversible conversion reactions of activators (O 2 , CO 2 , and sulde), which require highly efficient bi-functional catalysts due to the slow kinetics and high dissociation energy barriers involving multiple electron-transfer-proton coupling processes. [1][2][3] In fact, catalysts with dual/multiple functions not only play a key role in enhancing target product selectivity and accelerating reaction kinetics, but also are of great signicance in driving practical large-scale applications. [4][5][6] Among the various catalytic processes, oxygen electrocatalysis is considered as one of the most important reactions because of its extensive involvement in energy storage and chemical production.…”

Nanoporous-Structured Fe-NC Single-Atom Electrocatalysts Based on Lotus Seedpods and Industrial Acid Residues for Efficient Oxygen Reduction Reaction

“…These results strongly suggest the formation of more defects in FeNC-SAC-LS induced by a Lewis acid pretreatment. 32,33 XPS was used to further characterize the chemical state and content of the key elements in FeNC-SAC-LS (Figure S3a and Table S2). The high-resolution Fe 2p spectrum in Figure 3c presents the doublets of Fe 2+ 2p (710.2, 723.7 eV) and Fe 3+ 2p (713.7, 728.9 eV), in which the resonance at ∼529 eV assigned to the O−Fe bonding was absent, underlining ineffective coordination between O and Fe (Figure S3b).…”