Dual carbon-hosted Co-N3 enabling unusual reaction pathway for efficient oxygen reduction reaction

2021 ◽  
pp. 120390
Author(s):  
Hongbin Xu ◽  
Huaxian Jia ◽  
Haozhe Li ◽  
Jing Liu ◽  
Xiangwen Gao ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reaction Pathway ◽  
Reduction Reaction ◽  
Unusual Reaction

Electrochemical and spectroscopic characterization of a dicobalt macrocyclic Pacman complex in the catalysis of the oxygen reduction reaction in acid media

2013 ◽  
Vol 17 (04) ◽  
pp. 252-258 ◽  
Author(s):  
Qinggang He ◽  
Xiao Cheng ◽  
Ying Wang ◽  
Ruimin Qiao ◽  
Wanli Yang ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reaction Pathway ◽  
Spectroscopic Characterization ◽  
Reduction Reaction ◽  
Acid Media ◽  
Crystal Fields ◽  
Mononuclear Cobalt ◽  
X Ray Absorption

The dicobalt complex [ Co2(L2) ] of a Schiff-base pyrrole macrocycle adopts a Pacman structure in solution and the solid state and shows much greater catalytic activity and selectivity for the four-electron oxygen reduction reaction (ORR) than the mononuclear cobalt phthalocyanine (CoPc) counterpart. Soft X-ray absorption spectroscopy (XAS) shows that the Co center in Co2(L2) is of the same valence as mononuclear CoPc . However, the former complex shows higher unoccupied Co 3d density which is believed to be beneficial for electron transfers. Furthermore, the XAS data suggests that the crystal fields for Co2(L2) and CoPc are different, and that an interaction remains between two Co atoms in Co2(L2) . DFT calculations imply that the sterically hindered, cofacial structure of the dicobalt complex is critical for the operation of the four-electron reaction pathway during the ORR.

Switching the Oxygen Reduction Reaction Pathway via Tailoring the Electronic Structure of FeN4/C Catalysts

ACS Catalysis ◽  
2021 ◽  
pp. 13020-13027
Author(s):  
Yanping Zhu ◽  
Jiejie Li ◽  
Yubin Chen ◽  
Jian Zou ◽  
Qingqing Cheng ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reaction Pathway ◽  
Reduction Reaction

scholarly journals Intermetallic Pd3Pb nanocubes with high selectivity for the 4-electron oxygen reduction reaction pathway

Nanoscale ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 2532-2541 ◽  
Author(s):  
Jocelyn T. L. Gamler ◽  
Kihyun Shin ◽  
Hannah M. Ashberry ◽  
Yifan Chen ◽  
Sandra L. A. Bueno ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
High Selectivity ◽  
Reaction Pathway ◽  
Reduction Reaction

Pd-Based nanoparticles are excellent alternatives to the typically used Pt-based materials that catalyze fuel cell reactions.

Carbon-Supported Spinel Nanoparticle MnCo2O4 as a Cathode Catalyst towards Oxygen Reduction Reaction in Dual-Chamber Microbial Fuel Cell

2015 ◽  
Vol 68 (6) ◽  
pp. 987 ◽  
Author(s):  
Dengping Hu ◽  
Guangyao Zhang ◽  
Juan Wang ◽  
Qin Zhong
Keyword(s):  
Carbon Black ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Microbial Fuel Cells ◽  
Coupling Effect ◽  
Reaction Pathway ◽  
Reduction Reaction ◽  
Cathode Catalyst ◽  
Dual Chamber

The poor kinetics of oxygen reduction reaction (ORR) in neutral media and ambient temperature limit the performance of microbial fuel cells (MFCs). So higher-performing, low-cost oxygen reduction catalysts play a key role in power output. Through direct nanoparticle nucleation and growth on carbon black, a nanocomposite of manganese cobaltite and carbon black (in situ-MnCo2O4/C) was synthesized via a facile hydrothermal method. Subsequently, the in situ-MnCo2O4/C samples were characterized. The results show that the MnCo2O4 nanoparticles with a crystalline spinel structure are well dispersed on carbon black. Electrochemical measurements reveal that in situ-MnCo2O4/C demonstrates excellent ORR catalytic activity, which may account for the synergetic coupling effect between MnCo2O4 and carbon black. The ORR on as-prepared in situ-MnCo2O4/C hybrid mainly favours a direct 4-electron reaction pathway in alkaline solution. Moreover, in situ-MnCo2O4/C was used as an alternative catalyst for ORR in dual-chamber MFC. The obtained maximum power density is 545 mW m–2, which is far higher than that of the plain cathode (Pmax = 214 mW m–2) and slightly lower than that of commercial Pt/C catalyst (Pmax = 689 mW m–2). This study implies that in situ-MnCo2O4/C nanocomposite is an efficient and cost-effective cathode catalyst for practical MFC application.

Enhancing Oxygen Reduction Reaction Activity of α-MnO2 Nanowires Through Ag Doping

NANO ◽  
2020 ◽  
Vol 15 (09) ◽  
pp. 2050115
Author(s):  
Zixu Wu ◽  
Guangxing Li ◽  
Qin Liao ◽  
Ruida Ding ◽  
Xuze Zuo ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Fuel Cells ◽  
Oxygen Reduction Reaction ◽  
Manganese Oxide ◽  
Oxygen Reduction ◽  
High Performance ◽  
Large Scale ◽  
Reaction Pathway ◽  
Reduction Reaction ◽  
Ag Doping

Enhancing the catalytic activity of manganese oxide in oxygen reduction reaction (ORR) is a key issue for its large-scale application in metal-air fuel cells. Ag-doped [Formula: see text]-MnO2 nanowires without Ag or Ag2O have been successfully synthesized via a facile hydrothermal method, and the changes in both the structure and electrochemical catalytic performances after Ag doping are investigated. Compared with the pristine [Formula: see text]-MnO2, the as-prepared Ag-doped MnO2 exhibits a significantly enhanced catalytic activity in both ORR and Mg-air fuel cell application. With Ag/Mn ratio of 1:25, Ag-doped MnO2 exhibits a typical 4e-reaction pathway and presents a 163 mV higher half-wave potential than that of the pristine [Formula: see text]-MnO2. Furthermore, it demonstrates a power density of 75.1[Formula: see text]mW[Formula: see text]cm[Formula: see text] at current density of 134.5[Formula: see text]mA[Formula: see text]cm[Formula: see text] in the Mg-air fuel cells. The enhanced ORR performances are considered to be contributed from the activation of surface lattice oxygen, the improvement in conductivity and the increase in oxygen vacancies of [Formula: see text]-MnO2. These findings provide new understanding for developing high-performance manganese oxide catalysts.

The bifurcation point of the oxygen reduction reaction on Au–Pd nanoalloys

2016 ◽  
Vol 188 ◽  
pp. 257-278 ◽  
Author(s):  
Jakub Staszak-Jirkovský ◽  
Elisabet Ahlberg ◽  
Itai Panas ◽  
David J. Schiffrin
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Bifurcation Point ◽  
Reaction Pathway ◽  
Mechanistic Model ◽  
Direct Synthesis ◽  
Reduction Reaction ◽  
Acid Media ◽  
Energy Conversion And Storage ◽  
And Storage

The oxygen reduction reaction is of major importance in energy conversion and storage. Controlling electrocatalytic activity and its selectivity remains a challenge of modern electrochemistry. Here, first principles calculations and analysis of experimental data unravel the mechanism of this reaction on Au–Pd nanoalloys in acid media. A mechanistic model is proposed from comparison of the electrocatalysis of oxygen and hydrogen peroxide reduction on different Au–Pd ensembles. A H2O production channel on contiguous Pd sites proceeding through intermediates different from H2O2 and OOHσ adsorbate is identified as the bifurcation point for the two reaction pathway alternatives to yield either H2O or H2O2. H2O2 is a leaving group, albeit reduction of H2O2 to H2O can occur by electrocatalytic HO–OH dissociation that is affected by the presence of adsorbed OOHσ. Similarities and differences between electrochemical and direct synthesis from H2 + O2 reaction on Au–Pd nanoalloys are discussed.

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