Clarifying the controversial catalytic active sites of Co3O4 for the oxygen evolution reaction

2019 ◽  
Vol 7 (40) ◽  
pp. 23191-23198 ◽  
Author(s):  
Yong Xu ◽  
Fengchu Zhang ◽  
Tian Sheng ◽  
Tao Ye ◽  
Ding Yi ◽  
...  

Controversial results still exist about the activities of tetrahedral (Co2+) and octahedral (Co3+) sites in Co3O4 toward the OER. Theoretical and experimental data confirm that octahedral sites are responsible for the OER, using model catalysts.

2020 ◽  
Vol 13 (11) ◽  
pp. 4225-4237
Author(s):  
Xin Bo ◽  
Rosalie K Hocking ◽  
Si Zhou ◽  
Yibing Li ◽  
Xianjue Chen ◽  
...  

The catalytic active sites of NiFe and NiFeCr (oxy)hydroxides are revealed by operando spectroscopic techonologies for alkaline water oxidation.


2017 ◽  
Vol 19 (24) ◽  
pp. 5809-5817 ◽  
Author(s):  
Haidong Yang ◽  
Yu Long ◽  
Yan Zhu ◽  
Ziming Zhao ◽  
Ping Ma ◽  
...  

The highly efficient OER performance of the ultrathin cobalt hydroxides nanosheets is due to the elongated Co–OOHbonds generated from crystal lattice distortion, which can serve as the efficiently catalytic active sites.


2020 ◽  
Author(s):  
Ioannis Spanos ◽  
Justus Masa ◽  
Aleksandar Zeradjanin ◽  
Robert Schlögl

AbstractThere is an ongoing debate on elucidating the actual role of Fe impurities in alkaline water electrolysis, acting either as reactivity mediators or as co-catalysts through synergistic interaction with the main catalyst material. This perspective summarizes the most prominent oxygen evolution reaction (OER) mechanisms mostly for Ni-based oxides as model transition metal catalysts and highlights the effect of Fe incorporation on the catalyst surface in the form of impurities originating from the electrolyte or co-precipitated in the catalyst lattice, in modulating the OER reaction kinetics, mechanism and stability. Graphic Abstract


Nanoscale ◽  
2021 ◽  
Author(s):  
Ya-Nan Zhou ◽  
Ruo-Yao Fan ◽  
Yu-Ning Cao ◽  
Hui-Ying Wang ◽  
Bin Dong ◽  
...  

The oriental distribution and strong conjunction of Fe active sites in multiple metals hydroxides are very crucial to modulate the activity and stability for efficient oxygen evolution reaction (OER). Whereas,...


Author(s):  
Kaiyao Wu ◽  
Fei Chu ◽  
Yuying Meng ◽  
Kaveh Edalati ◽  
Qingsheng Gao ◽  
...  

Transition metal-based amorphous alloys have attracted increasing attention as precious-metal-free electrocatalysts for oxygen evolution reaction (OER) of water splitting due to their high macro-conductivity and abundant surface active sites. However,...


2021 ◽  
Author(s):  
Qiaoling Kang ◽  
Dawei Lai ◽  
Wenyin Tang ◽  
Qingyi Lu ◽  
Feng Gao

Effective strategies to increase the intrinsic activity by electronic modulation and to increase the number of active sites by structural design are discussed for improving the oxygen evolution activities of NiFe alloys.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gang Zhou ◽  
Peifang Wang ◽  
Hao Li ◽  
Bin Hu ◽  
Yan Sun ◽  
...  

AbstractOxygen evolution reaction (OER) plays a determining role in electrochemical energy conversion devices, but challenges remain due to the lack of effective low-cost electrocatalysts and insufficient understanding about sluggish reaction kinetics. Distinguish from complex nano-structuring, this work focuses on the spin-related charge transfer and orbital interaction between catalysts and intermediates to accelerate catalytic reaction kinetics. Herein, we propose a simple magnetic-stimulation approach to rearrange spin electron occupation in noble-metal-free metal-organic frameworks (MOFs) with a feature of thermal-differentiated superlattice, in which the localized magnetic heating in periodic spatial distribution makes the spin flip occur at particular active sites, demonstrating a spin-dependent reaction pathway. As a result, the spin-rearranged Co0.8Mn0.2 MOF displays mass activities of 3514.7 A gmetal−1 with an overpotential of ~0.27 V, which is 21.1 times that of pristine MOF. Our findings provide a new paradigm for designing spin electrocatalysis and steering reaction kinetics.


2021 ◽  
Vol 9 ◽  
Author(s):  
Yubing Yan

Developing efficient and low-cost replacements for noble metals as electrocatalysts for the oxygen evolution reaction (OER) remain a great challenge. Herein, we report a needle-like cobalt carbonate hydroxide hydrate (Co(CO3)0.5OH·0.11H2O) nanoarrays, which in situ grown on the surface of carbon cloth through a facile one-step hydrothermal method. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterizations demonstrate that the Co(CO3)0.5OH nanoarrays with high porosity is composed of numerous one-dimensional (1D) nanoneedles. Owing to unique needle-like array structure and abundant exposed active sites, the Co(CO3)0.5OH@CC only requires 317 mV of overpotential to reach a current density of 10 mA cm−2, which is much lower than those of Co(OH)2@CC (378 mV), CoCO3@CC (465 mV) and RuO2@CC (380 mV). For the stability, there is no significant attenuation of current density after continuous operation 27 h. This work paves a facile way to the design and construction of electrocatalysts for the OER.


2018 ◽  
Vol 30 (32) ◽  
pp. 1802912 ◽  
Author(s):  
Ye Zhou ◽  
Shengnan Sun ◽  
Jiajia Song ◽  
Shibo Xi ◽  
Bo Chen ◽  
...  

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