scholarly journals Metallosupramolecular Polymer Precursor Design for Multi-Element Co-Doped Carbon Shells with Improved Oxygen Reduction Reaction Catalytic Activity

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 102 ◽  
Author(s):  
Yuzhe Wu ◽  
Yuntong Li ◽  
Jie Mao ◽  
Haiyang Wu ◽  
Tong Wu ◽  
...  

Heteroatom-doped carbon materials have been extensively studied in the field of electrochemical catalysis to solve the challenges of energy shortage. In particular, there is vigorous research activity in the design of multi-element co-doped carbon materials for the improvement of electrochemical performance. Herein, we developed a supramolecular approach to construct metallosupramolecular polymer hollow spheres, which could be used as precursors for the generation of carbon shells co-doped with B, N, F and Fe elements. The metallosupramolecular polymer hollow spheres were fabricated through a simple route based on the Kirkendall effect. The in situ reaction between the boronate polymer spheres and Fe3+ could easily control the component and shell thickness of the precursors. The as-prepared multi-element co-doped carbon shells showed excellent catalytic activity in an oxygen reduction reaction, with onset potential (Eonset) 0.91 V and half-wave (Ehalf-wave) 0.82 V vs reversible hydrogen electrode (RHE). The fluorine element in the carbon matrix was important for the improvement of oxygen reduction reaction (ORR) activity performance through designing the control experiment. This supramolecular approach may afford a new route to explore good activity and a low-cost catalyst for ORR.

2020 ◽  
Vol 16 (4) ◽  
pp. 625-638
Author(s):  
Leila Samiee ◽  
Sedigheh Sadegh Hassani

Background: Porous carbon materials are promising candidate supports for various applications. In a number of these applications, doping of the carbon framework with heteroatoms provides a facile route to readily tune the carbon properties. The oxygen reduction reaction (ORR), where the reaction can be catalyzed without precious metals is one of the common applications for the heteroatom-doped carbons. Therefore, heteroatom doped catalysts might have a promising potential as a cathode in Microbial fuel cells (MFCs). MFCs have a good potential to produce electricity from biological oxidization of wastes at the anode and chemical reduction at the cathode. To the best of our knowledge, no studies have been yet reported on utilizing Sulfur trioxide pyridine (STP) and CMK-3 for the preparation of (N and S) doped ordered porous carbon materials. The presence of highly ordered mesostructured and the synergistic effect of N and S atoms with specific structures enhance the oxygen adsorption due to improving the electrocatalytic activity. So the optimal catalyst, with significant stability and excellent tolerance of methanol crossover can be a promising candidate for even other storage and conversion devices. Methods: The physico-chemical properties of the prepared samples were determined by Small Angle X-ray Diffraction (SAXRD), N2 sorption-desorption, Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy (FESEM) and X-ray Photoelectron Spectroscopy (XPS). The prepared samples were further applied for oxygen reduction reaction (ORR) and the optimal cathode was tested with the Microbial Fuel Cell (MFC) system. Furthermore, according to structural analysis, The HRTEM, and SAXRD results confirmed the formation of well-ordered hexagonal (p6mm) arrays of mesopores in the direction of (100). The EDS and XPS approved that N and S were successfully doped into the CMK-3 carbon framework. Results: Among all the studied CMK-3 based catalysts, the catalyst prepared by STP precursor and pyrolysis at 900°C exhibited the highest ORR activity with the onset potential of 1.02 V vs. RHE and 4 electron transfer number per oxygen molecule in 0.1 M KOH. The high catalyst durability and fuel-crossover tolerance led to stable performance of the optimal cathode after 5000 s operation, while the Pt/C cathode-based was considerably degraded. Finally, the MFC system with the optimal cathode displayed 43.9 mW·m-2 peak power density showing even reasonable performance in comparison to a Pt/C 20 wt.%.cathode. Conclusions: The results revealed that the synergistic effect of nitrogen and sulfur co-doped on the carbon substrate structure leads to improvement in catalytic activity. Also, it was clearly observed that the porous structure and order level of the carbon substrate could considerably change the ORR performance.


2019 ◽  
Vol 467-468 ◽  
pp. 75-83 ◽  
Author(s):  
André L. Cazetta ◽  
Lucas Spessato ◽  
Karen C. Bedin ◽  
Isis P.F.A. Souza ◽  
Rafael A. Araújo ◽  
...  

Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1163
Author(s):  
Ning Cui ◽  
Kexiao Bi ◽  
Wei Sun ◽  
Qianqian Wu ◽  
Yinan Li ◽  
...  

MOF–derived porous carbon is a type of promising catalyst to replace expensive Pt–based catalysts for oxygen reduction reaction (ORR). The catalytic activity for ORR depends closely on pyrolysis conditions. In this work, a Co–doped ZIF–8 material was chosen as a research object. The effect of pyrolysis conditions (temperature, heating rate, two–step heating) on the ORR performance of ZIF–derived carbon catalysts was systematically studied. The Co–ZIF–8 catalyst carbonized at 900 °C exhibits better ORR catalytic activity than that carbonized at 800 °C and 1000 °C. Moreover, a low heating rate can enhance catalytic activity. Two–step pyrolysis is proven to be an effective way to improve the performance of catalysts. Reducing the heating rate in the low–temperature stage is more beneficial to the ORR performance, compared to the heating rate in the high–temperature stage. The results show that the Co–ZIF–8 catalyst exhibits the best performance when the precursor was heated to 350 °C at 2 °C/min, and then heated to 900 °C at 5 °C/min. The optimum Co–ZIF–8 catalyst shows a half–wave potential of 0.82 V and a current density of 5.2 mA·cm−2 in 0.1 M KOH solution. It also exhibits high content of defects and good graphitization. TEM mapping shows that Co and N atoms are highly dispersed in the polyhedral carbon skeleton. However, two–step pyrolysis has no significant effect on the stability of the catalyst.


2018 ◽  
Vol 5 (11) ◽  
pp. 2985-2991 ◽  
Author(s):  
Yunjie Zhou ◽  
Yue Sun ◽  
Huibo Wang ◽  
Cheng Zhu ◽  
Jin Gao ◽  
...  

A N, B co-doped carbon material exhibits excellent catalytic activity for an oxygen reduction reaction.


2015 ◽  
Vol 3 (24) ◽  
pp. 12718-12722 ◽  
Author(s):  
Shaofang Fu ◽  
Chengzhou Zhu ◽  
He Li ◽  
Dan Du ◽  
Yuehe Lin

One-step synthesis of cobalt and nitrogen co-doped carbon nanotubes and their catalytic activity for the oxygen reduction reaction.


RSC Advances ◽  
2021 ◽  
Vol 11 (23) ◽  
pp. 13906-13911
Author(s):  
Can Sun ◽  
Xinde Duan ◽  
Jiajun Song ◽  
Mengxian Zhang ◽  
Yachao Jin ◽  
...  

ZIF-derived RhNC-900 bifunctional electrocatalysts for the oxygen reduction reaction and hydrogen evolution reaction have been prepared via a simple and scalable method, exhibiting excellent catalytic activity and promising performance.


Author(s):  
Ziyan Kong ◽  
Tao Liu ◽  
Kun Hou ◽  
Lunhui Guan

Developing efficient and stable non-precious metal (NPM) oxygen reduction reaction (ORR) catalyst in an environmentally benign and economically affordable way is highly desired but remains challenging. Manganese and nitrogen co-doped...


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