Increased activity in the oxygen evolution reaction by Fe4+-induced hole states in perovskite La1−xSrxFeO3

2020 ◽  
Vol 8 (8) ◽  
pp. 4407-4415 ◽  
Author(s):  
Zechao Shen ◽  
Yongbin Zhuang ◽  
Weiwei Li ◽  
Xiaochun Huang ◽  
Freddy E. Oropeza ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Energy Barrier ◽  
Hole State ◽  
Reaction Intermediates ◽  
Increased Activity

Hole for faster OER: The hole state induced by Fe4+ promotes the OER process. It reduces the energy barrier for electron transfer at the interface and facilitates a faster electron transfer from reaction intermediates to the catalyst.

The electron-transfer intermediates of the oxygen evolution reaction (OER) as polarons by in situ spectroscopy

2021 ◽  
Author(s):  
Hanna Lyle ◽  
Suryansh Singh ◽  
Michael Paolino ◽  
Ilya Vinogradov ◽  
Tanja Cuk
Keyword(s):  
Electron Transfer ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Catalytic Reactions ◽  
In Situ Spectroscopy ◽  
Chemical Bonds

The conversion of diffusive forms of energy (electrical and light) into short, compact chemical bonds by catalytic reactions regularly involves moving a carrier from an environment that favors delocalization to one that favors localization.

Boosting the oxygen evolution reaction using defect-rich ultra-thin ruthenium oxide nanosheets in acidic media

2020 ◽  
Vol 13 (12) ◽  
pp. 5143-5151 ◽  
Author(s):  
Zhi Liang Zhao ◽  
Qi Wang ◽  
Xiang Huang ◽  
Qi Feng ◽  
Shuang Gu ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Energy Barrier ◽  
Ruthenium Oxide ◽  
Acidic Media

A Ru vacancy decreases the energy barrier from O* to OOH*, thus dramatically enhancing the OER performance of defect-rich RuO2 nanosheets.

scholarly journals Spin-Polarized Oxygen Evolution Reaction Under Magnetic Field

2021 ◽  
Author(s):  
Xiao Ren ◽  
Tianze Wu ◽  
Yuanmiao Sun ◽  
Yan Li ◽  
Guoyu Xian ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Transfer ◽  
Triplet State ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Spin Exchange ◽  
Momentum Conservation ◽  
Exclusion Principle ◽  
Fast Kinetics ◽  
Spin Polarized

<p><a></a><a>The oxygen evolution reaction (OER) is the bottleneck that limits the energy efficiency of water-splitting. The process involves four electrons’ transfer and the generation of triplet state O<sub>2</sub> from singlet state species (OH<sup>- </sup>or H<sub>2</sub>O). Recently, explicit spin selection was described as a possible way to promote OER in alkaline conditions, but the specific spin-polarized kinetics remains unclear. </a><a></a><a>Here, we report that </a><a>by using ferromagnetic ordered catalysts as the spin polarizer for spin selection under </a><a></a><a>a constant magnetic field</a>, <a>the OER can be enhanced.</a> However, it does not applicable to non-ferromagnetic catalysts. We found that the spin <a>polarization occurs at the first electron transfer step in OER</a>, where <a></a><a>coherent spin exchange happens </a>between the <a></a><a>ferromagnetic</a> catalyst and the adsorbed oxygen species <a>with fast kinetics</a>, under the principle of spin angular momentum conservation. In the next three electron transfer steps, as the adsorbed O species adopt fixed spin direction, the OER electrons need to follow the Hund rule and Pauling exclusion principle, thus to carry out spin polarization spontaneously and finally lead to the generation of triplet state O<sub>2</sub>. Here, we showcase spin-polarized kinetics of oxygen evolution reaction, which gives references in the understanding and design of spin-dependent catalysts.</p>

scholarly journals Highly active Bifunctional Lamo3 (M=Cr, Mn, Fe, Co, Ni) Perovskites for Oxygen Reduction and Oxygen Evolution Reaction in Alkaline Media

2020 ◽  
Author(s):  
Areeba Hameed ◽  
Khulood Logade ◽  
Naba Ali ◽  
Priya Ghosh ◽  
Sadiya Shafath ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
High Energy ◽  
Literature Survey ◽  
Experimental Results ◽  
Alkaline Media ◽  
Reaction Intermediates ◽  
Perovskite Catalyst ◽  
Rate Determining Step

Lanthanum based electrocatalytically active perovskites, LaMO3 (M=Cr, Mn, Fe, Co, Ni), were synthesized using a single step solution combustion synthesis technique. The perovskites showed exceptional performance for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline medium. Based on the experimental results and literature survey, it is suggested that the exceptional activity of Mn and Co based lanthanum perovskite catalyst could be due to the optimum stabilization of reaction intermediates involved in the rate-determining step (RDS) of ORR/OER. According to crystal field theory (CFT), the d-orbital of transition metals are affected by the octahedral arrangement of six negative charges around it. The d orbital degenerates by splitting into two high energy (eg) and three lower energy orbitals (t2g) while maintaining the same average energy level. The rate-determining step in the ORR/OER reaction that based on the eg orbital filling of B site transition metal cations If the d-electrons are less, the valence state goes up and lowering the eg orbital filling that results in strong adsorption of oxygenated species on the B site (strong B-OH bond). This strong bonding limits the overall reaction rate by the slow desorption of OH and its derivatives during ORR/OER. Similarly, too high eg filling causes weak adsorption of oxygenated species that limits the reaction through the slow adsorption of reactants. Therefore, to enhance the activity of ORR/OER reaction it is required to balance the adsorption and desorption of the reactants and the intermediate respectively. The better way is to optimize the eg orbital filling to be nearly 1 (eg = 1).Based on the experimental results and literature survey, it is suggested that the exceptional activity of Mn and Co based lanthanum perovskite catalyst could be due to the optimum stabilization of reaction intermediates involved in the rate-determining step (RDS) of ORR and OER.

Nickel nitride–black phosphorus heterostructure nanosheets for boosting the electrocatalytic activity towards the oxygen evolution reaction

2019 ◽  
Vol 7 (38) ◽  
pp. 22063-22069 ◽  
Author(s):  
Tong Wu ◽  
Shaoning Zhang ◽  
Kejun Bu ◽  
Wei Zhao ◽  
Qingyuan Bi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Transfer Rate ◽  
Active Sites ◽  
Hydroxyl Groups ◽  
High Electron ◽  
Electron Transfer Rate ◽  
Alkaline Fuel Cells ◽  
Nickel Nitride

The extraordinary oxygen evolution reaction (OER) in alkaline fuel cells and water-splitting systems demands a high electron transfer rate and catalysts with numerous active sites and massive hydroxyl groups.

scholarly journals Beyond the volcano limitations in electrocatalysis – oxygen evolution reaction

2014 ◽  
Vol 16 (27) ◽  
pp. 13682-13688 ◽  
Author(s):  
Niels Bendtsen Halck ◽  
Valery Petrykin ◽  
Petr Krtil ◽  
Jan Rossmeisl
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Surface Reactivity ◽  
Reaction Intermediates ◽  
Adsorption Energies

Oxygen evolution catalysis is restricted by the interdependence of adsorption energies of the reaction intermediates and the surface reactivity.

scholarly journals Spin-polarized oxygen evolution reaction under magnetic field

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiao Ren ◽  
Tianze Wu ◽  
Yuanmiao Sun ◽  
Yan Li ◽  
Guoyu Xian ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Transfer ◽  
Triplet State ◽  
Oxygen Evolution ◽  
Spin Polarization ◽  
Oxygen Evolution Reaction ◽  
Spin Exchange ◽  
Exclusion Principle ◽  
Fast Kinetics ◽  
Spin Polarized

AbstractThe oxygen evolution reaction (OER) is the bottleneck that limits the energy efficiency of water-splitting. The process involves four electrons’ transfer and the generation of triplet state O2 from singlet state species (OH- or H2O). Recently, explicit spin selection was described as a possible way to promote OER in alkaline conditions, but the specific spin-polarized kinetics remains unclear. Here, we report that by using ferromagnetic ordered catalysts as the spin polarizer for spin selection under a constant magnetic field, the OER can be enhanced. However, it does not applicable to non-ferromagnetic catalysts. We found that the spin polarization occurs at the first electron transfer step in OER, where coherent spin exchange happens between the ferromagnetic catalyst and the adsorbed oxygen species with fast kinetics, under the principle of spin angular momentum conservation. In the next three electron transfer steps, as the adsorbed O species adopt fixed spin direction, the OER electrons need to follow the Hund rule and Pauling exclusion principle, thus to carry out spin polarization spontaneously and finally lead to the generation of triplet state O2. Here, we showcase spin-polarized kinetics of oxygen evolution reaction, which gives references in the understanding and design of spin-dependent catalysts.

Fine regulation of electron transfer in Ag@Co3O4 nanoparticles for boosting oxygen evolution reaction

2021 ◽  
Author(s):  
Xiwen Du ◽  
Zhe Li ◽  
Yi Feng ◽  
Xiuyao Lang ◽  
Wenjing Kang ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Shell Structure ◽  
Shell Thickness ◽  
Core Shell ◽  
Co3o4 Nanoparticles ◽  
Fine Regulation ◽  
Core Shell Structure

In this study, a core-shell structure (Ag@Co3O4) was constructed to modify valance state of cobalt cations precisely by continuously adjusting the shell thickness. There exists a volcano relationship between valence...

Interfacial electron transfer of heterostructured MIL-88A/Ni(OH)2 enhances the oxygen evolution reaction in alkaline solutions

2020 ◽  
Vol 8 (6) ◽  
pp. 3311-3321 ◽  
Author(s):  
Zhengxin Qian ◽  
Keke Wang ◽  
Kexin Shi ◽  
Zhaoqin Fu ◽  
Zequn Mai ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Alkaline Solutions ◽  
Interfacial Electron Transfer ◽  
Interfacial Charge Transfer ◽  
Interfacial Charge

A facile strategy is developed to create a MIL-88A/Ni(OH)2 heterostructure, where the interfacial charge transfer significantly boosted the OER performance.

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