Applications of two dimensional material-MXene for proton exchange membrane fuel cells (PEMFCs) and water electrolysis

2020 ◽  
Vol 16 ◽  
Author(s):  
Chanchan Fan ◽  
Peng Zhang ◽  
Ranran Wang ◽  
Yezhu Xu ◽  
Xingrui Sun ◽  
...  

: A new kind of two-dimensional (2D) materials MXene (early transition metal carbides, nitrides and carbonitrides) is obtained by selective etching the A element from the MAX phases. MXene exhibits both the metallic conductivity and the hydrophilic nature due to its metal layer structure and hydroxyl or oxygen terminated surfaces. This review provides an overview of the MXene used in the electrolytes and electrodes for the fuel cells and water splitting. MXene with functional groups termination could construct ion channels that significantly benefits to the ion conductivity through the electrolyte. The metal supported by MXene interaction offers electronic, compositional, and geometric effects that could enhance the catalytic activity and stability. MXene have already shown promising performance for fuel cells and water electrolysis. Herein, the etching and intercalation methods of MXene in recent years are summarized. The applications of MXene for fuel cells electrolyte, catalyst and water splitting catalyst are revealed to provide more brief idea for MXene used as new energy materials.

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Jalal Yazji ◽  
Alicia Li Jen Keow ◽  
Hamza Zaidi ◽  
Luke T. Torres ◽  
Christopher Leroy ◽  
...  

Abstract Fine buoyancy control is essential for underwater robots to maintain neutral buoyancy despite dynamic changes in environmental conditions. This paper introduces a novel buoyancy control system that uses reversible fuel cells (RFC) as a mass-to-volume engine to change the underwater robots' buoyancy. The RFC uses both the water electrolysis process and fuel cell reaction to produce and consume gases in a flexible bladder for volume change. Unlike conventional actuators such as motors and pistons used in buoyancy control, this mechanism is silent, compact, and energy-efficient. A dynamic model that described the dynamics of the RFC-enabled buoyancy change is presented. Then, a proportional-derivative (PD) controller is designed to position the device at any depth underwater. A prototype device is built to validate the dynamic model and the performance of the feedback controller. Experimental results demonstrate a fine depth control performance with 4 cm accuracy and 90 s settling time. The compact buoyancy design is readily integrable with small underwater robots for fine depth change allowing the robots to save actuation energy.


2020 ◽  
Vol 455 ◽  
pp. 227952 ◽  
Author(s):  
Chao Cai ◽  
Zhaohui Wan ◽  
Yan Rao ◽  
Wei Chen ◽  
Jiangfeng Zhou ◽  
...  

AIChE Journal ◽  
1998 ◽  
Vol 44 (11) ◽  
pp. 2410-2422 ◽  
Author(s):  
Vladimir Gurau ◽  
Hongtan Liu ◽  
Sadik Kakaç

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2064 ◽  
Author(s):  
S. Filice ◽  
G. Urzì ◽  
R. G. Milazzo ◽  
S. M. S. Privitera ◽  
S. A. Lombardo ◽  
...  

The aim of this work is to evaluate the possible use of Nexar™ polymer, a sulfonated pentablock copolymer (s-PBC), whose structure is formed by tert-butyl styrene, hydrogenated isoprene, sulfonated styrene, hydrogenated isoprene, and tert-butyl styrene (tBS-HI-SS-HI-tBS), as a more economical and efficient alternative to Nafion® membrane for proton exchange membrane (PEM) electrolysis cells. Furthermore, we have studied a new methodology for modification of gas diffusion layers (GDL) by depositing Pt and TiO2 nanoparticles at the cathode and anode side, respectively, and a protective polymeric layer on their surface, allowing the improvement of the contact with the membrane. Morphological, structural, and electrical characterization were performed on the Nexar™ membrane and on the modified GDLs. The use of modified GDLs positively affects the efficiency of the water electrolysis process. Furthermore, Nexar™ showed higher water uptake and conductivity with respect to Nafion®, resulting in an increased amount of current generated during water electrolysis. In conclusion, we show that Nexar™ is an efficient and cheaper alternative to Nafion® as the proton exchange membrane in water splitting applications and we suggest a possible methodology for improving GDLs’ properties. These results meet the urgent need for low-cost materials and processes for hydrogen production.


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