Ag nanoparticle-loaded to MnO2 with rich oxygen vacancies and Mn3+ for the synergistically enhanced oxygen reduction reaction

He, Manchao; Turup, Zulhumar; Jin, Xuekun; Chen, Fengjuan

doi:10.1016/j.ijhydene.2023.03.283

Cited by 11 publications

(6 citation statements)

References 66 publications

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“…In addition, using the RRDE technique, the LSV curves of NP-AM-5 at 1600 rpm were measured, as shown in Figure d, and the calculated result presents that the electron transfer number (inset of Figure d) always keeps in 4e – during the reaction. , The perfect 4e – transfer in the oxygen reduction process suggests that O 2 in the electrolyte is completely reduced, without the formation of peroxides origined from 2e – transfer. In fact, the peroxides could be decomposed by MnO x in time to maintain the efficient 4e – transfer process at all times . This also illustrates that alloying of Ag–Mn and the synergistic effect of MnO x in NP-AM-5 are effective ways to improve the ORR activity.…”

Section: Resultsmentioning

confidence: 85%

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Nanoporous Ag–Mn Alloy Electrocatalysts via Dealloying for Enhanced Oxygen Reduction Reaction in Zinc-Air Batteries

Guo,

Chen,

Wang

et al. 2024

ACS Appl. Nano Mater.

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Zinc-air batteries (ZABs) are an emerging energy technology that is environmentally friendly and has a high theoretical energy density, but their commercial application is limited by the oxygen reduction reaction (ORR). Silver-based nanocatalysts can effectively improve the ORR performance. In this paper, a nanoporous Ag−Mn (NP-AM) electrocatalyst with bicontinuous ligaments was prepared by a combination of the melt-spinning technique and dealloying method. Theoretical calculations show that Mn-doped Ag(111) indicates a shift of the d-band center toward the Fermi energy level, which improves the adsorption energy of the OOH and thus reduces the overpotential of the decision step in the ORR process. Among them, the electrocatalyst NP-AM-5 reached a half-wave potential of 0.81 V (vs reversible hydrogen electrode (RHE)) with a limiting current density of −5.63 mA cm −2 . Tests showed that its ORR process almost completely undergoes 4e − transfer with higher conversion efficiency and also exhibits better long-term stability in comparison to commercial Pt/C electrocatalysts. When used as the cathode of a zinc-air battery, the maximum power density reaches 140 mW cm −2 . The discharge voltage can be maintained at about 1.2 V for a long period of time by discharging at a constant current of 10 mA cm −2 , and the specific capacity is calculated to be 724 mAh g −1 .

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Section: Resultsmentioning

confidence: 85%

“…In fact, the peroxides could be decomposed by MnO x in time to maintain the efficient 4e − transfer process at all times. 60 This also illustrates that alloying of Ag−Mn and the synergistic effect of MnO x in NP-AM-5 are effective ways to improve the ORR activity.…”

Section: Electrochemical Properties Of Np-am In the Orrmentioning

confidence: 84%

Nanoporous Ag–Mn Alloy Electrocatalysts via Dealloying for Enhanced Oxygen Reduction Reaction in Zinc-Air Batteries

Guo,

Chen,

Wang

et al. 2024

ACS Appl. Nano Mater.

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“…The Tafel slope values for Ag/MnO 2 _MWCNT catalysts (in potential range from −0.15 V to −0.25 V vs. SCE) were similar and stayed between −81 and −94 mV regardless of the nominal thickness of the sputter-deposited Ag layers (Table 2). Tafel slope values of −91 mV and −163 mV were obtained for Ag-based catalysts where Ag was deposited onto MnO 2 nanorods (Ag/MnO 2 ) and clean MnO 2 nanorods, respectively [64]. The Tafel slope value for polycrystalline bulk Ag electrode remained around −80 mV.…”

Section: Oxygen Reduction Reaction Studiesmentioning

confidence: 98%

“…For example, Liu et al argue that the enhanced stability might come from a synergistic effect between Ag and Mn 3 O 4 nanoparticles [34]. The synergistic effect is argued to include an ensemble effect between Ag and Mn 3 O 4 nanoparticles, where on Mn 3 O 4 , hydroperoxide ions form and then diffuse or re-adsorb on AgNPs, where they can disproportionate or be further reduced to OH − ions [34,35,64]. Part of the synergistic effect might arise from the electron transfer from carbon substrate to Mn 3 O 4 , which creates a positive charge on adjacent carbon surfaces allowing for side-on O 2 adsorption, where O-O bonding is weakened, and it facilitates the four-electron pathway [34,56].…”

Section: Oxygen Reduction Reaction Studiesmentioning

confidence: 99%

“…Part of the synergistic effect might arise from the electron transfer from carbon substrate to Mn 3 O 4 , which creates a positive charge on adjacent carbon surfaces allowing for side-on O 2 adsorption, where O-O bonding is weakened, and it facilitates the four-electron pathway [34,56]. Hu et al argued that in the case of Ag/MnO 2 catalysts, oxygen vacancies could play a role in the ORR invigorating synergistic effect [64]. In the case of Ag/MnO 2 _MWCNT2 catalysts, there may be fewer available carbon sites along MnO 2 , and only the ensemble effect between Ag and MnO 2 might affect the electroreduction of the formed peroxide intermediates, which in turn could induce a greater decrease in half-wave potential after AST for Ag/MnO 2 _MWCNT2 catalysts.…”

Section: Oxygen Reduction Reaction Studiesmentioning

confidence: 99%

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Ag Sputter-Deposited on MnO2-Carbon Nanotube Nanocomposites as Electrocatalysts for Oxygen Reduction Reaction in Alkaline Media

et al. 2023

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As energy demand increases, new energy conversion methods are also sought. In this study, two MnO2 and multiwalled carbon nanotube (MWCNT) composites were prepared and decorated with silver using magnetron sputtering, to evaluate their electrocatalytic activity towards the oxygen reduction reaction (ORR). Three nominal thicknesses of Ag layers were used, 5, 10 and 20 nm. The physicochemical characterisation was carried out using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, as well as X-ray photoelectron spectroscopy. The substrate materials (MnO2-MWCNT) were also investigated by X-ray diffraction analysis. The electrochemical studies of the ORR revealed that the activity and stability of the composite catalysts depend on the substrate material and the Ag layer thickness.

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Dual‐Carbon Assisted Oxygen Vacancy Engineering for Optimizing Mn(III) Sites to Enhance Zn–air Battery Performances

Zhou,

Xu,

et al. 2024

Adv Funct Materials

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Owing to kinetic‐sluggish nature of electrocatalytic oxygen transformation processes, it is pivotal to develop durable and efficient bifunctional air electrode catalysts for fabricating high‐performance Zn–air batteries (ZABs). In this work, oxygen vacancy (Ov) induced Mn(III) sites optimization is achieved via nano‐micro structure modulation. Protonated carbon nitride (p‐C3N4) is applied as a structure‐stiffening module to immobilize α‐MnO2 on N/P‐doped active carbon (NPAC) and induce Ov construction. X‐ray adsorption spectra (XAS) disclose the formation of Ov and Mn(III) sites in MCC, the unit coordination structure is well maintained with the aid of a dual‐carbon strategy. Mn(III) sites efficiently catalyze oxygen reduction/evolution reaction (ORR/OER), MCC shows high half‐wave potential (E1/2) of 0.88 V for ORR and low potential at 10 mA cm−2 (Ej = 10) of 1.64 V for OER. According to density functional theory (DFT) simulations analysis, the gorgeous bifunctional activity is owing to that optimized charge distribution facilitates the intermediates transformation. Aqueous ZABs based on MCC manifests high peak power density of 452 mW cm−2 and durable cycling stability of 1640 h. Quasi‐solid‐state ZABs based on MCC also show satisfactory performances (175 mW cm−2, 105 h). This work provides the route to develop efficient and durable electrocatalyst for constructing ZABs with long lifespan and high‐power‐density.

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Ag nanoparticle-loaded to MnO2 with rich oxygen vacancies and Mn3+ for the synergistically enhanced oxygen reduction reaction

Cited by 11 publications

References 66 publications

Nanoporous Ag–Mn Alloy Electrocatalysts via Dealloying for Enhanced Oxygen Reduction Reaction in Zinc-Air Batteries

Nanoporous Ag–Mn Alloy Electrocatalysts via Dealloying for Enhanced Oxygen Reduction Reaction in Zinc-Air Batteries

Ag Sputter-Deposited on MnO2-Carbon Nanotube Nanocomposites as Electrocatalysts for Oxygen Reduction Reaction in Alkaline Media

Dual‐Carbon Assisted Oxygen Vacancy Engineering for Optimizing Mn(III) Sites to Enhance Zn–air Battery Performances

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