N-Doped Graphene as an Efficient Metal-Free Electrocatalyst for Indirect Nitrate Reduction Reaction

N-doped graphene samples with different N species contents were prepared by a two-step synthesis method and evaluated as electrocatalysts for the nitrate reduction reaction (NORR) for the first time. In an acidic solution with a saturated calomel electrode as reference, the pyridinic-N dominant sample (NGR2) had an onset of 0.932 V and a half-wave potential of 0.833 V, showing the superior activity towards the NORR compared to the pyrrolic-N dominant N-doped graphene (onset potential: 0.850 V, half-wave potential: 0.732 V) and the pure graphene (onset potential: 0.698 V, half-wave potential: 0.506 V). N doping could significantly boost the NORR performance of N-doped graphene, especially the contribution of pyridinic-N. Density functional theory calculation revealed the pyridinic-N facilitated the desorption of NO, which was kinetically involved in the process of the NORR. The findings of this work would be valuable for the development of metal-free NORR electrocatalysts.

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An ultra-dispersive, nonprecious metal MOF–FeZn catalyst with good oxygen reduction activity and favorable stability in acid

Journal of Materials Science ◽

10.1007/s10853-021-05803-7 ◽

2021 ◽

Vol 56 (14) ◽

pp. 8600-8612

Author(s):

Qing Zhao ◽

Cheng Wang ◽

Haifeng Wang ◽

Jianlong Wang

Keyword(s):

Oxygen Reduction ◽

High Performance ◽

Reduction Reaction ◽

Graphitic Carbon ◽

Potential Cycling ◽

Onset Potential ◽

Wave Potential ◽

Reduction Activity ◽

Half Wave Potential ◽

Half Wave

AbstractDevelopment of the more stable nonprecious oxygen reduction reaction (ORR) catalyst is of great significance nowadays. Herein, a high-performance iron-doped integral uniform macrocyclic organic framework (MOF–FeZn) catalyst is synthesized through a combined hydrothermal and pyrolysis process, showing favorable ORR activity and stability in acid. This as-synthesized MOF–FeZn catalyst displays high porous and graphitic structures with sufficient catalytic active dopants of pyridinic N, Fe–N, pyrrolic N, graphitic N, making it a promising ORR candidate catalyst with high electrochemical stability. The onset potential, half-wave potential and limited diffusion current density of MOF–FeZn are 0.93 V @ 0.1 mA cm−2, 0.768 V@ 2.757 mA cm−2 and 5.5 mA cm−2, respectively, which are comparable to the state-of-the-art nonprecious catalyst and commercial Pt/C. ORR catalysis on MOF–FeZn follows the nearly four-electron path. What is more, MOF–FeZn can sustain the 10,000 cycles electrochemical potential cycling process in acid with the half-wave potential changed only 21 mV, superior to the reduction of 149 mV for Pt/C. The well-developed integral uniform structures, homogeneously dispersed carbides and nitrides protected by the highly graphitic carbon layers and the better agglomeration suppression of nanoparticles by the confined graphitic carbon layers on catalyst can significantly enhance the catalytic activity and stability of MOF–FeZn.

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Modified Carbon Nanotubes: Surface Properties and Activity in Oxygen Reduction Reaction

Catalysts ◽

10.3390/catal11111354 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1354

Author(s):

Vera Bogdanovskaya ◽

Inna Vernigor ◽

Marina Radina ◽

Vladimir Sobolev ◽

Vladimir Andreev ◽

...

Keyword(s):

Carbon Nanotubes ◽

Zeta Potential ◽

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Surface Area ◽

Surface Properties ◽

Reduction Reaction ◽

Wave Potential ◽

Half Wave Potential ◽

Half Wave

In order to develop highly efficient and stable catalysts for oxygen reduction reaction (ORR) that do not contain precious metals, it is necessary to modify carbon nanotubes (CNT) and define the effect of the modification on their activity in the ORR. In this work, the modification of CNTs included functionalization by treatment in NaOH or HNO3 (soft and hard conditions, respectively) and subsequent doping with nitrogen (melamine was used as a precursor). The main parameters that determine the efficiency of modified CNT in ORR are composition and surface area (XPS, BET), hydrophilic–hydrophobic surface properties (method of standard contact porosimetry (MSP)) and zeta potential (dynamic light scattering method). The activity of CNT in ORR was assessed following half-wave potential, current density within kinetic potential range and the electrochemically active surface area (SEAS). The obtained results show that the modification of CNT with oxygen-containing groups leads to an increase in hydrophilicity and, consequently, SEAS, as well as the total (overall) current. Subsequent doping with nitrogen ensures further increase in SEAS, higher zeta potential and specific activity in ORR, reflected in the shift of the half-wave potential by 150 mV for CNTNaOH-N and 110 mV for CNTHNO3-N relative to CNTNaOH and CNTHNO3, respectively. Moreover, the introduction of N into the structure of CNTHNO3 increases their corrosion stability.

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Cobalt decorated nitrogen-doped carbon bowls as efficient electrocatalysts for the oxygen reduction reaction

Chemical Communications ◽

10.1039/c9cc10036a ◽

2020 ◽

Vol 56 (32) ◽

pp. 4488-4491 ◽

Cited By ~ 4

Author(s):

Haobin Zhong ◽

Changwei Shi ◽

Jiantao Li ◽

Ruohan Yu ◽

Qiang Yu ◽

...

Keyword(s):

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Reduction Reaction ◽

Nitrogen Doped ◽

Wave Potential ◽

Half Wave Potential ◽

Half Wave ◽

Nitrogen Doped Carbon

Cobalt decorated nitrogen-doped carbon bowls (Co@NCB) demonstrate better ORR performance than Pt/C in terms of half-wave potential and stability.

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Cathodic action of lead malate complexes at the dropping mercury electrode

Australian Journal of Chemistry ◽

10.1071/ch9730971 ◽

1973 ◽

Vol 26 (5) ◽

pp. 971 ◽

Cited By ~ 4

Author(s):

SC Khurana ◽

CM Gupta

Keyword(s):

Stability Constants ◽

Mercury Electrode ◽

Reduction Reaction ◽

Ligand Concentration ◽

Wave Potential ◽

Half Wave Potential ◽

Half Wave ◽

Dropping Mercury Electrode ◽

The Stability

The electrode reduction reaction of lead malate, involving deprotonated malate ion and a proton, between pK1 and pK2 values of the acid has been investigated. At pH < pK1 protonated ion participates and a proton is involved. The effect of ligand concentration on the half-wave potential of Pb2+ has been investigated and the stability constants of species so formed computed.

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Bimetallic ZIF derived Co nanoparticle anchored N-doped porous carbons for an efficient oxygen reduction reaction

Inorganic Chemistry Frontiers ◽

10.1039/c9qi01487j ◽

2020 ◽

Vol 7 (4) ◽

pp. 946-952 ◽

Cited By ~ 4

Author(s):

Kaili Li ◽

Daohao Li ◽

Liangkui Zhu ◽

Zhuangzhuang Gao ◽

Qianrong Fang ◽

...

Keyword(s):

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

High Performance ◽

Reduction Reaction ◽

Porous Carbons ◽

Wave Potential ◽

Half Wave Potential ◽

Half Wave ◽

Reaction Performance

A high-performance electrocatalytic material was derived from a new bimetallic ZIF precursor, exhibiting excellent oxygen reduction reaction performance with a half-wave potential (E1/2) of 0.849 V, superior to that of commercial Pt/C.

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One-pot synthesis of nitrogen and sulfur co-doped graphene as efficient metal-free electrocatalysts for the oxygen reduction reaction

Chemical Communications ◽

10.1039/c4cc00440j ◽

2014 ◽

Vol 50 (37) ◽

pp. 4839-4842 ◽

Cited By ~ 240

Author(s):

Xin Wang ◽

Jie Wang ◽

Deli Wang ◽

Shuo Dou ◽

Zhaoling Ma ◽

...

Keyword(s):

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Current Density ◽

Reaction Pathway ◽

Reduction Reaction ◽

One Pot ◽

Onset Potential ◽

Metal Free ◽

Doped Graphene ◽

Co Doped

Novel N and S co-doped graphene (NSG) was prepared by annealing GO with thiourea. The NSG electrodes show a direct four-electron reaction pathway, higher onset potential, current density and stability than undoped graphene.

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Nitrogen and sulfur co-doped graphene aerogels as an efficient metal-free catalyst for oxygen reduction reaction in an alkaline solution

RSC Advances ◽

10.1039/c5ra22136f ◽

2016 ◽

Vol 6 (27) ◽

pp. 22781-22790 ◽

Cited By ~ 29

Author(s):

Mei Wu ◽

Zhiyu Dou ◽

Jingjing Chang ◽

Lili Cui

Keyword(s):

Alkaline Solution ◽

Reduction Reaction ◽

Limiting Current ◽

Random Orientation ◽

Onset Potential ◽

Metal Free ◽

Limiting Current Density ◽

3D Network ◽

Doped Graphene ◽

Co Doped

N–S-GAs 900 exhibit an interconnected porous 3D network with random orientation, crumpled sheets in SEM. The onset potential and limiting current density of N–S-GAs 900 are more positive and larger than other catalysts.

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