scholarly journals Boosting oxygen reduction activity and enhancing stability through structural transformation of layered lithium manganese oxide

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xuepeng Zhong ◽  
M’hamed Oubla ◽  
Xiao Wang ◽  
Yangyang Huang ◽  
Huiyan Zeng ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Density Functional ◽  
Manganese Oxides ◽  
Rational Design ◽  
Reaction Pathway ◽  
Density Functional Theory Calculations ◽  
Cost Effective ◽  
Reduction Reaction ◽  
Proton Exchange ◽  
Type Structure

AbstractStructural degradation in manganese oxides leads to unstable electrocatalytic activity during long-term cycles. Herein, we overcome this obstacle by using proton exchange on well-defined layered Li2MnO3 with an O3-type structure to construct protonated Li2-xHxMnO3-n with a P3-type structure. The protonated catalyst exhibits high oxygen reduction reaction activity and excellent stability compared to previously reported cost-effective Mn-based oxides. Configuration interaction and density functional theory calculations indicate that Li2-xHxMnO3-n has fewer unstable O 2p holes with a Mn3.7+ valence state and a reduced interlayer distance, originating from the replacement of Li by H. The former is responsible for the structural stability, while the latter is responsible for the high transport property favorable for boosting activity. The optimization of both charge states to reduce unstable O 2p holes and crystalline structure to reduce the reaction pathway is an effective strategy for the rational design of electrocatalysts, with a likely extension to a broad variety of layered alkali-containing metal oxides.

scholarly journals Noble metal supported hexagonal boron nitride for the oxygen reduction reaction: a DFT study

2019 ◽  
Vol 1 (1) ◽  
pp. 132-139 ◽  
Author(s):  
Seoin Back ◽  
Samira Siahrostami
Keyword(s):  
Boron Nitride ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Density Functional ◽  
Hexagonal Boron Nitride ◽  
Density Functional Theory Calculations ◽  
Cost Effective ◽  
Reduction Reaction ◽  
Functional Theory ◽  
The Stability

Discovering active, stable and cost-effective catalysts for the oxygen reduction reaction (ORR) is of utmost interest for commercialization of fuel cells. Herein, we use density functional theory calculations to systematically study metal supported hexagonal boron nitride as ORR catalysts. Our results indicate that this strategy is a promising to increase the stability against CO poisoning as well as to activate inert h-BN toward the ORR.

scholarly journals Highly active and selective oxygen reduction to H2O2 on boron-doped carbon for high production rates

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yang Xia ◽  
Xunhua Zhao ◽  
Chuan Xia ◽  
Zhen-Yu Wu ◽  
Peng Zhu ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Density Functional ◽  
High Selectivity ◽  
Density Functional Theory Calculations ◽  
Reduction Reaction ◽  
Production Rates ◽  
Practical Applications ◽  
Highly Active ◽  
Boron Doped ◽  
Oxidized Carbon

AbstractOxygen reduction reaction towards hydrogen peroxide (H2O2) provides a green alternative route for H2O2 production, but it lacks efficient catalysts to achieve high selectivity and activity simultaneously under industrial-relevant production rates. Here we report a boron-doped carbon (B-C) catalyst which can overcome this activity-selectivity dilemma. Compared to the state-of-the-art oxidized carbon catalyst, B-C catalyst presents enhanced activity (saving more than 210 mV overpotential) under industrial-relevant currents (up to 300 mA cm−2) while maintaining high H2O2 selectivity (85–90%). Density-functional theory calculations reveal that the boron dopant site is responsible for high H2O2 activity and selectivity due to low thermodynamic and kinetic barriers. Employed in our porous solid electrolyte reactor, the B-C catalyst demonstrates a direct and continuous generation of pure H2O2 solutions with high selectivity (up to 95%) and high H2O2 partial currents (up to ~400 mA cm−2), illustrating the catalyst’s great potential for practical applications in the future.

scholarly journals A density functional theory study of the oxygen reduction reaction on the (111) and (100) surfaces of cobalt(II) oxide

2019 ◽  
Vol 44 (2) ◽  
pp. 122-131
Author(s):  
Bangchang Qin ◽  
Yang Tian ◽  
Pengxiang Zhang ◽  
Zuoyin Yang ◽  
Guoxin Zhang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Free Energy ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Gibbs Free Energy ◽  
Density Functional ◽  
Rational Design ◽  
Reduction Reaction ◽  
Functional Theory ◽  
Associative Mechanism

Density functional theory calculations were employed to investigate the electrochemical oxygen reduction reaction on the (111) and (100) surfaces of cobalt(II) oxide. Different mechanisms were applied to evaluate the oxygen reduction reaction performance of cobalt(II) oxide structures in terms of the Gibbs free energy and density of states. A variety of intermediate structures based on associative and dissociative mechanisms were constructed and optimized. As a result, we estimated the catalytic activity by calculating the free energy of the intermediates and constructing free energy diagrams, which suggested that the oxygen reduction reaction Gibbs free energy on cobalt(II) oxide (111) and (100) surfaces based on the associative mechanism is smaller than that based on the dissociative mechanism, demonstrating that the associative mechanism should be more likely to be the oxygen reduction reaction pathway. Moreover, the theoretical oxygen reduction reaction activity on the cobalt(II) oxide (111) surface was found to be higher than that on the cobalt(II) oxide (100) surface. These results shed light on the rational design of high-performance cobalt(II) oxide oxygen reduction reaction catalysts.

The oxygen reduction reaction mechanism on Pt(111) from density functional theory calculations

2010 ◽  
Vol 55 (27) ◽  
pp. 7975-7981 ◽  
Author(s):  
Vladimir Tripković ◽  
Egill Skúlason ◽  
Samira Siahrostami ◽  
Jens K. Nørskov ◽  
Jan Rossmeisl
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Reduction Reaction ◽  
Functional Theory

scholarly journals Unveiling the high-activity origin of single-atom iron catalysts for oxygen reduction reaction

2018 ◽  
Vol 115 (26) ◽  
pp. 6626-6631 ◽  
Author(s):  
Liu Yang ◽  
Daojian Cheng ◽  
Haoxiang Xu ◽  
Xiaofei Zeng ◽  
Xin Wan ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Density Functional ◽  
Reduction Reaction ◽  
Proton Exchange ◽  
Alkaline Media ◽  
Single Atom ◽  
Iron Catalysts ◽  
Grand Challenge ◽  
Orr Activity

It is still a grand challenge to develop a highly efficient nonprecious-metal electrocatalyst to replace the Pt-based catalysts for oxygen reduction reaction (ORR). Here, we propose a surfactant-assisted method to synthesize single-atom iron catalysts (SA-Fe/NG). The half-wave potential of SA-Fe/NG is only 30 mV less than 20% Pt/C in acidic medium, while it is 30 mV superior to 20% Pt/C in alkaline medium. Moreover, SA-Fe/NG shows extremely high stability with only 12 mV and 15 mV negative shifts after 5,000 cycles in acidic and alkaline media, respectively. Impressively, the SA-Fe/NG-based acidic proton exchange membrane fuel cell (PEMFC) exhibits a high power density of 823 mW cm−2. Combining experimental results and density-functional theory (DFT) calculations, we further reveal that the origin of high-ORR activity of SA-Fe/NG is from the Fe-pyrrolic-N species, because such molecular incorporation is the key, leading to the active site increase in an order of magnitude which successfully clarifies the bottleneck puzzle of why a small amount of iron in the SA-Fe catalysts can exhibit extremely superior ORR activity.

First-principles transition state study of oxygen reduction reaction on Pt (111) surface modified by subsurface transition metals

2012 ◽  
Vol 1384 ◽  
Author(s):  
Zhiyao Duan ◽  
Aditi Datta ◽  
Guofeng Wang
Keyword(s):  
Transition Metals ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Reduction Reaction ◽  
Functional Theory ◽  
State Study ◽  
Surface Modified

ABSTRACTWe have performed first-principles density functional theory calculations to investigate how subsurface 3d transition metals M (M = Ni, Co, Fe, Ti, or V) affect the energetics and mechanisms of oxygen reduction reaction (ORR) on the outermost Pt mono-surface layer of Pt/M (111) surfaces. We found that the alteration of the ORR mechanism pathway can explain the activity enhancement for ORR on the Pt/M (111) surfaces.

MnOx Enhanced Atomically Dispersed Iron-Nitrogen-Carbon Catalyst for Oxygen Reduction Reaction

2021 ◽  
Author(s):  
Shichao Ding ◽  
Zhaoyuan Lyu ◽  
Erik Sarnello ◽  
Mingjie Xu ◽  
Lingzhe Fang ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Proton Exchange Membrane ◽  
Cost Effective ◽  
Reduction Reaction ◽  
Proton Exchange ◽  
Single Atom ◽  
Carbon Catalyst ◽  
Highly Efficient ◽  
Exchange Membrane

Cost-effective and highly efficient Fe-N‑C single-atom catalysts (SACs) have been known as the most promising potential Pt substitutes for the cathodic oxygen reduction reaction (ORR) in proton exchange membrane fuel...

A density functional study on the oxygen reduction reaction mechanism on FeN2-doped graphene

2018 ◽  
Vol 42 (9) ◽  
pp. 6873-6879 ◽  
Author(s):  
Yuewen Yang ◽  
Kai Li ◽  
Yanan Meng ◽  
Ying Wang ◽  
Zhijian Wu
Keyword(s):  
Reaction Mechanism ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Density Functional ◽  
Rational Design ◽  
Reduction Reaction ◽  
Functional Study ◽  
Highly Active ◽  
Doped Graphene ◽  
Commercial Applications

The rational design of heteroatom doped graphene as a highly active and non-noble oxygen reduction reaction (ORR) electrocatalyst is significant for the commercial applications of fuel cells.

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