scholarly journals Green algae and gelatine derived nitrogen rich carbon as an outstanding competitor to Pt loaded carbon catalysts

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anna Ilnicka ◽  
Malgorzata Skorupska ◽  
Magdalena Tyc ◽  
Kinga Kowalska ◽  
Piotr Kamedulski ◽  
...  
Keyword(s):  
Energy Conversion ◽  
Green Algae ◽  
Active Sites ◽  
Noble Metals ◽  
Electrode Materials ◽  
Electronic Conductivity ◽  
Energy System ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Porous Carbons

AbstractThe development of effective catalysts for the oxygen reduction reaction (ORR) is a significant challenge in energy conversion systems, e.g., Zn–air batteries. Herein, green-algae- and gelatine-derived porous, nitrogen-rich carbons were extensively investigated as electrode materials for electrochemical catalytic reactions. These carbon-based catalysts were designed and optimized to create a metal-free catalyst via templating, carbonization, and subsequent removal of the template. The additional incorporation of graphene improved electronic conductivity and enhanced the electrochemical catalytic reaction. Porous carbons with heteroatoms were used as effective platinum-free ORR electrocatalysts for energy conversion; the presence of nitrogen in the carbon provided more active sites for ORR. Our catalyst also displayed notable durability in a rechargeable Zn–air battery energy system. More importantly, the nitrogen-containing porous carbons were found to have comparable ORR performance in alkaline media to commercially available electrocatalysts. The manuscript demonstrates that nitrogen atom insertion is an appropriate approach when aiming to eliminate noble metals from the synthesis route. N-doped carbons are competitive materials compared to reference platinum-based catalysts.

scholarly journals Migration-Prevention Strategy to Fabricate Single-Atom Fe Implanted N-Doped Porous Carbons for Efficient Oxygen Reduction

Research ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Dong-Li Meng ◽  
Chun-Hui Chen ◽  
Jun-Dong Yi ◽  
Qiao Wu ◽  
Jun Liang ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Active Sites ◽  
Carbonaceous Material ◽  
Nitrogen Sources ◽  
Reduction Reaction ◽  
Prevention Strategy ◽  
Alkaline Media ◽  
Single Atom ◽  
Porous Carbons ◽  
Iron Species

It is highly desired but challenging to achieve highly active single-atom Fe sites from iron-based metal-organic frameworks (MOFs) for efficient oxygen reduction reaction (ORR) due to the easy aggregation of iron species and formation of the inactive Fe-based particles during pyrolysis. Herein, a facile migration-prevention strategy is developed involving the incorporation of polyaniline (PANI) into the pores of iron porphyrinic-based MOF PCN-224(Fe) and followed by pyrolysis to obtain the single-atom Fe implanted N-doped porous carbons material PANI@PCN-224(Fe)-900. The introduced PANI inside the pores of PCN-224(Fe) not only served as protective fences to prevent the aggregation of the iron species during thermal annealing, but also acted as nitrogen sources to increase the nitrogen content and form Fe-Nx-C active sites. Compared with the pristine PCN-224(Fe) derived carbonization sample containing Fe-based particles, the carbonaceous material PANI@PCN-224(Fe)-900 without inactive Fe-based particles exhibited superb ORR electrocatalytic activity with a more positive half-wave potential, significantly improved stability in both alkaline media, and more challenging acidic condition. The migration-prevention strategy provides a new way to fabricate atomically dispersed metal active sites via pyrolysis approach for promoting catalysis.

scholarly journals Superior FexN electrocatalyst derived from 1,1′-diacetylferrocene for oxygen reduction reaction in alkaline and acidic media

2020 ◽  
Vol 9 (1) ◽  
pp. 843-852
Author(s):  
Hunan Jiang ◽  
Jinyang Li ◽  
Mengni Liang ◽  
Hanpeng Deng ◽  
Zuowan Zhou
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Current Density ◽  
Active Sites ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Acidic Media ◽  
Onset Potential ◽  
Acidic And Alkaline Media ◽  
The Stability

AbstractAlthough Fe–N/C catalysts have received increasing attention in recent years for oxygen reduction reaction (ORR), it is still challenging to precisely control the active sites during the preparation. Herein, we report FexN@RGO catalysts with the size of 2–6 nm derived from the pyrolysis of graphene oxide and 1,1′-diacetylferrocene as C and Fe precursors under the NH3/Ar atmosphere as N source. The 1,1′-diacetylferrocene transforms to Fe3O4 at 600°C and transforms to Fe3N and Fe2N at 700°C and 800°C, respectively. The as-prepared FexN@RGO catalysts exhibited superior electrocatalytic activities in acidic and alkaline media compared with the commercial 10% Pt/C, in terms of electrochemical surface area, onset potential, half-wave potential, number of electrons transferred, kinetic current density, and exchange current density. In addition, the stability of FGN-8 also outperformed commercial 10% Pt/C after 10000 cycles, which demonstrates the as-prepared FexN@RGO as durable and active ORR catalysts in acidic media.

scholarly journals Nanobelts-constructed Porous TiO2-B@SnS2 Heterostructure Hybrids for Enhance Lithium Storage Performance

2021 ◽  
Author(s):  
Chao Cai ◽  
Meiyu Song ◽  
Qixiang Ou ◽  
Jianmei Li ◽  
changsheng an
Keyword(s):  
Active Sites ◽  
Electrode Materials ◽  
Theoretical Calculations ◽  
Electronic Conductivity ◽  
Lithium Ion ◽  
Cycle Performance ◽  
Electrode Structure ◽  
Lithium Storage ◽  
Volume Collapse ◽  
Alloy Type

Abstract Alloy-type anodes materials possess broad prospects for excellent electrochemical property lithium-ion batteries owing to its high theoretical capacity and excellent electronic conductivity. However, this type electrode materials experience poor kinetics and tremendous volume collapse during the repeated lithiation-delithiation process. Herein, an efficient method to provide a fast transmission channel and suppress the volume collapse during the discharge/charge process by constructing the heterostructure between porous TiO2-B nanoblets and few-layer SnS2 nanosheets interface, which provides high-active sites for the nucleation and growth of SnS2 nanosheets, and inhibits the agglomeration of SnS2 nanosheets. Both experimental results and theoretical calculations definite that porous TiO2 nanobelts provides more chemical active sites for the adsorption and transmission of lithium ion and then effectively improve the stability the electrode structure. As a result, TiO2-B@SnS2 hybrid exhibits excellent rate and cycle performance. This work paves a way to design and construction of high performance alloy-type anode materials.

scholarly journals Improving the Performance of Zn-Air Batteries with N-Doped Electroexfoliated Graphene

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2115 ◽  
Author(s):  
Anna Ilnicka ◽  
Malgorzata Skorupska ◽  
Piotr Romanowski ◽  
Piotr Kamedulski ◽  
Jerzy P. Lukaszewicz
Keyword(s):  
Catalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Noble Metals ◽  
Electrode Materials ◽  
Low Cost ◽  
Rapid Development ◽  
Reduction Reaction ◽  
Graphene Sheets ◽  
High Catalytic Activity ◽  
Energy Storage Devices

The constantly growing demand for active, durable, and low-cost electrocatalysts usable in energy storage devices, such as supercapacitors or electrodes in metal-air batteries, has triggered the rapid development of heteroatom-doped carbon materials, which would, among other things, exhibit high catalytic activity in the oxygen reduction reaction (ORR). In this article, a method of synthesizing nitrogen-doped graphene is proposed. Few-layered graphene sheets (FL-graphene) were prepared by electrochemical exfoliation of commercial graphite in a Na2SO4 electrolyte with added calcium carbonate as a separator of newly-exfoliated FL-graphene sheets. Exfoliated FL-graphene was impregnated with a suspension of green algae used as a nitrogen carrier. Impregnated FL-graphene was carbonized at a high temperature under the flow of nitrogen. The N-doped FL-graphene was characterized through instrumental methods: high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. Electrochemical performance was determined using cyclic voltamperometry and linear sweep voltamperometry to check catalytic activity in ORR. The N-doped electroexfoliated FL-graphene obeyed the four-electron transfer pathways, leading us to further test these materials as electrode components in rechargeable zinc-air batteries. The obtained results for Zn-air batteries are very important for future development of industry, because the proposed graphene electrode materials do not contain any heavy and noble metals in their composition.

scholarly journals Metallic Organic Framework-Derived Fe, N, S co-doped Carbon as a Robust Catalyst for the Oxygen Reduction Reaction in Microbial Fuel Cells

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3846 ◽  
Author(s):  
Xiao Luo ◽  
Wuli Han ◽  
Han Ren ◽  
Qingzuo Zhuang
Keyword(s):  
Fuel Cells ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Microbial Fuel Cells ◽  
Active Sites ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
X Ray ◽  
Co Doped ◽  
Organic Framework

Oxygen reduction reaction (ORR) provides a vital role for microbial fuel cells (MFCs) due to its slow reaction kinetics compared with the anodic oxidation reaction. How to develop new materials with low cost, high efficacy, and eco-friendliness which could replace platinum-based electrocatalysis is a challenge that we have to resolve. In this work, we accomplished this successfully by means of a facile strategy to synthesize a metallic organic framework-derived Fe, N, S co-doped carbon with FeS as the main phase. The Fe/S@N/C-0.5 catalyst demonstrated outstandingly enhanced ORR activity in neutral PBS and alkaline media, compared to that of commercial 20% Pt-C catalyst. Here, we started-up and operated two parallel single-chamber microbial fuel cells of an air cathode, and those cathode catalysts were Fe/S@N/C-0.5 and commercial Pt-C (20% Pt), respectively. Scanning electron microscopy (SEM) elaborated that the Fe/S@N/C-0.5 composite did not change the polyhedron morphology of ZIF-8. According to X-ray diffractometry(XRD) curves, the main crystal phase of the resulted Fe/S@N/C-0.5 was FeS. The chemical environment of N, S, and Fe which are anticipated to be the high-efficiency active sites of ORR for MFCs were investigated by X-ray photoelectron spectroscopic(XPS). Nitrogen adsorption/desorption techniques were used to calculate the pore diameter distribution. In brief, the obtained Fe/S@N/C-0.5 material exhibited a pronounced reduction potential at 0.861 V (versus Reversible Hydrogen Electrode(RHE)) in 0.1M KOH solution and –0.03 V (vs. SCE) in the PBS solution, which both outperform the benchmark platinum-based catalysts. Fe/S@N/C-0.5-MFC had a higher Open Circuit Voltage(OCV) (0.71 V), stronger maximum power density (1196 mW/m2), and larger output voltage (0.47 V) than the Pt/C-MFC under the same conditions.

An MOF-derived C@NiO@Ni electrocatalyst for N2 conversion to NH3 in alkaline electrolytes

2020 ◽  
Vol 4 (1) ◽  
pp. 164-170 ◽  
Author(s):  
Shijian Luo ◽  
Xiaoman Li ◽  
Wanguo Gao ◽  
Haiqiang Zhang ◽  
Min Luo
Keyword(s):  
Active Sites ◽  
Oxygen Vacancies ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Alkaline Electrolytes

MOF-derived C@NiO@Ni are proposed as an efficient electrocatalyst for N2 reduction reaction in alkaline media. Abundant oxygen vacancies and NiO/Ni interfaces can act as active sites for adsorbing nitrogen and proton, respectively.

scholarly journals Development of novel air electrode materials for the SOFC and SOEC technologies

2019 ◽  
Vol 108 ◽  
pp. 01019 ◽  
Author(s):  
Anna Niemczyk ◽  
Konrad Świerczek
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Electrode Materials ◽  
Operating Temperature ◽  
Electronic Conductivity ◽  
Reduction Reaction ◽  
Significant Decline ◽  
Solid Oxide ◽  
Air Electrode ◽  
Good Catalytic Activity ◽  
New Compounds

One of major goals in the development of solid oxide fuel cells and its reversible mode, solid oxide electrolyzer cells, is related to a decrease of the operating temperature, down to the intermediate range (600-800 °C) or even lower temperatures. However, this reduction causes an increase of the polarization resistance, especially for the air electrode, which results in a significant decline of the efficiency of the device. Therefore, it is essential to obtain new, thermally and chemically stable materials with the high ionic-electronic conductivity and good catalytic activity for the oxygen reduction reaction working in the decreased temperature range. At the same time, environmental and economic aspects have to be considered in the development of the new compounds. Promising cobalt-free electrode materials can be Cu-based oxides with the perovskite and perovskite-related structures.

scholarly journals Graphene/nitrogen-doped porous carbon sandwiches for the metal-free oxygen reduction reaction: conductivity versus active sites

2016 ◽  
Vol 4 (32) ◽  
pp. 12658-12666 ◽  
Author(s):  
M. Qiao ◽  
C. Tang ◽  
G. He ◽  
K. Qiu ◽  
R. Binions ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Porous Carbon ◽  
Active Sites ◽  
Electronic Conductivity ◽  
Hydrothermal Carbonization ◽  
Reduction Reaction ◽  
Active Nitrogen ◽  
Free Oxygen ◽  
Nitrogen Doped ◽  
Metal Free

Graphene/nitrogen-doped porous carbon sandwiches were prepared by hydrothermal carbonization. Once the electronic conductivity in the carbon–carbon hybrids reaches a certain value, the performance is controlled by the active nitrogen sites.

scholarly journals Insights into the role of an Fe–N active site in the oxygen reduction reaction on carbon-supported supramolecular catalysts

RSC Advances ◽  
2020 ◽  
Vol 10 (15) ◽  
pp. 8709-8716
Author(s):  
Lin Gu ◽  
Yunyun Dong ◽  
Yan Zhang ◽  
Bo Wang ◽  
Qing Yuan ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Active Site ◽  
Active Sites ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Supramolecular Catalysts

The PPYTZ–Fe/C catalyst containing Fe–N active sites exhibited high ORR catalytic activity and stability in alkaline media with a four-electron pathway progress.

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