alkaline electrolyte
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Molecules ◽  
2022 ◽  
Vol 27 (1) ◽  
pp. 328
Yifei Zhou ◽  
Lei Yan ◽  
Junhua Hou

The synthesis of metal-free carbon-based electrocatalysts for oxygen reduction reactions (ORR) to replace conventional Pt-based catalysts has become a hot spot in current research. This work proposes an activation-assisted carbonization strategy, to manufacture N-doped ultra-thin carbon nanosheets (GWS180M800) with high catalytic activity, namely, melamine is used as an accelerator/nitrogen source, and walnut green peels biological waste as a carbon source. The melamine acts as a nitrogen donor in the hydrothermal process, effectively enhancing the nitrogen doping rate. The content of pyridine nitrogen groups accounts for up to 48.5% of the total nitrogen content. Electrochemical tests show that the GWS180M800 has excellent ORR electrocatalytic activity and stability, and makes a quasi-four-electron ORR pathway clear in the alkaline electrolyte. The initial potential and half slope potential are as high as 1.01 and 0.82 V vs. RHE, respectively. The GWS180M800 catalyst has a better ability to avoid methanol cross poisoning than Pt/C has. Compared with 20 wt% Pt/C, GWS180M800 has improved methanol tolerance and stability. It is a metal-free biochar ORR catalyst with great development potential and application prospects. This result provides a new space for the preparation of valuable porous nano-carbon materials based on carbonaceous solid waste and provides new ideas for catalyzing a wide range of electrochemical reactions in the future.

Nanoscale ◽  
2022 ◽  
Hyungkuk Ju ◽  
Dong Han Seo ◽  
Sunki Chung ◽  
Xin Mao ◽  
Byeong Seon An ◽  

The electrochemical synthesis of ammonia at ambient temperature and pressure has a potential to replace conventional ammonia production process. However, low ammonia yield and poor long-term stability of the catalyst...

Ji Hye Kim ◽  
HyungKuk Ju ◽  
Byeong-Seon An ◽  
Yena An ◽  
Kanghee Cho ◽  

2021 ◽  
pp. 163509
Chunxia Niu ◽  
Hua Song ◽  
Yunzhen Chang ◽  
Wenjing Hou ◽  
Yanping Li ◽  

2021 ◽  
Kiran Kuruvinashetti ◽  
Nikolay Kornienko

The electrochemical synthesis of hydrogen peroxide (H2O2), a widely used oxidant, is emerging as a green alternative to the conventional anthraquinone method. In this work, Ni-based metal-organic nanosheet (Ni-MONs) catalysts constructed using a variety of linkers were studied as oxygen reduction catalysts. Using a host of analytical techniques, we reveal how modulating the terephthalic acid linker with hydroxy, amine, and fluorine groups impacts the resulting physical and electronic structure of the Ni catalytic sites. These changes further impact the selectivity for H2O2, with the Ni-Amine-MON reaching near 100% Faradaic efficiency at minimal overpotential for the 2e- H2O2 pathway in alkaline electrolyte. Finally, we translate the Ni-Amine-MON catalyst to a gas-diffusion reaction geometry and demonstrate a H2O2 partial current density of 200 mA/cm2 while maintaining 85% Faradaic efficiency. In all, this study puts forth a simple route to catalyst modulation for highly effective H2O2 electrosynthesis.

2021 ◽  
Vol 2131 (4) ◽  
pp. 042021
V Demyan ◽  
V Mikhailenko ◽  
I Zhukova

Abstract Within the framework of these studies, an electrochemical method for the synthesis of highly dispersed powders of copper compounds in aqueous solutions of alkalis is presented. The factors influencing the rate of production of nanoscale copper (II) oxide particles are determined. It is shown that during the anodic oxidation of copper by direct current, the speed of highly dispersed powders formation depends on current density, the nature of alkali cation, and the concentration of electrolyte solution. The mass loss of copper electrodes in NaOH solution is higher than in solutions of potassium hydroxide and lithium hydroxide by 10% and 12%, respectively. This experiment suggests that the studied alkalis act similarly on the anodic behavior of copper and the nature of cation does not significantly affect the speed of anodes destruction. The change in the concentration of alkali solution practically does not affect the mass loss of copper electrodes. The speed of copper oxidation remains almost constant over time, but noticeable weight loss and, accordingly, the speed of copper dissolution is achieved within 15 minutes. The speed of copper oxidation does not depend on current density. It is determined by the amount of electricity that has passed. The current density of 1 A/cm2 can be considered optimal.

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