scholarly journals Efficient CO2 electroreduction on facet-selective copper films with high conversion rate

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gong Zhang ◽  
Zhi-Jian Zhao ◽  
Dongfang Cheng ◽  
Huimin Li ◽  
Jia Yu ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Membrane Electrode Assembly ◽  
Membrane Electrode ◽  
Copper Films ◽  
Faradaic Efficiency ◽  
Polymer Binders ◽  
Co2 Electroreduction ◽  
High Conversion Rate ◽  
Insight Into

AbstractTuning the facet exposure of Cu could promote the multi-carbon (C2+) products formation in electrocatalytic CO2 reduction. Here we report the design and realization of a dynamic deposition-etch-bombardment method for Cu(100) facets control without using capping agents and polymer binders. The synthesized Cu(100)-rich films lead to a high Faradaic efficiency of 86.5% and a full-cell electricity conversion efficiency of 36.5% towards C2+ products in a flow cell. By further scaling up the electrode into a 25 cm2 membrane electrode assembly system, the overall current can ramp up to 12 A while achieving a single-pass yield of 13.2% for C2+ products. An insight into the influence of Cu facets exposure on intermediates is provided by in situ spectroscopic methods supported by theoretical calculations. The collected information will enable the precise design of CO2 reduction reactions to obtain desired products, a step towards future industrial CO2 refineries.

scholarly journals Stable, active CO2 reduction to formate via redox-modulated stabilization of active sites

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Le Li ◽  
Adnan Ozden ◽  
Shuyi Guo ◽  
F. Pelayo Garcı́a de Arquer ◽  
Chuanhao Wang ◽  
...  
Keyword(s):  
Active Sites ◽  
Structural Changes ◽  
Experimental Studies ◽  
Co2 Reduction ◽  
Membrane Electrode Assembly ◽  
Membrane Electrode ◽  
Faradaic Efficiency ◽  
Stable Production ◽  
Exchange Membrane

AbstractElectrochemical reduction of CO2 (CO2R) to formic acid upgrades waste CO2; however, up to now, chemical and structural changes to the electrocatalyst have often led to the deterioration of performance over time. Here, we find that alloying p-block elements with differing electronegativities modulates the redox potential of active sites and stabilizes them throughout extended CO2R operation. Active Sn-Bi/SnO2 surfaces formed in situ on homogeneously alloyed Bi0.1Sn crystals stabilize the CO2R-to-formate pathway over 2400 h (100 days) of continuous operation at a current density of 100 mA cm−2. This performance is accompanied by a Faradaic efficiency of 95% and an overpotential of ~ −0.65 V. Operating experimental studies as well as computational investigations show that the stabilized active sites offer near-optimal binding energy to the key formate intermediate *OCHO. Using a cation-exchange membrane electrode assembly device, we demonstrate the stable production of concentrated HCOO– solution (3.4 molar, 15 wt%) over 100 h.

In-Situ Tem Investigation During Thermal Cycling of thin Copper Films

1996 ◽  
Vol 436 ◽  
Author(s):  
R.-M. Keller ◽  
W. Sigle ◽  
S. P. Baker ◽  
O. Kraft ◽  
E. Arzt
Keyword(s):  
Grain Growth ◽  
Room Temperature ◽  
Dislocation Motion ◽  
In Situ Tem ◽  
Copper Films ◽  
Stress Evolution ◽  
Cu Films ◽  
Transmission Electron ◽  
Insight Into

AbstractIn-situ transmission electron microscopy (TEM) was performed to study grain growth and dislocation motion during temperature cycles of Cu films with and without a cap layer. In addition, the substrate curvature method was employed to determine the corresponding stresstemperature curves from room temperature up to 600°C. The results of the in-situ TEM investigations provide insight into the microstructural evolution which occurs during the stress measurements. Grain growth occurred continuously throughout the first heating cycle in both cases. The evolution of dislocation structure observed in TEM supports an explanation of the stress evolution in both capped and uncapped films in terms of dislocation effects.

In-Situ Measurements of Water Transfer Due to Different Mechanisms in a PEM Fuel Cell

2007 ◽  
Author(s):  
Attila Husar ◽  
Andrew Higier ◽  
Hongtan Liu
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Membrane Electrode Assembly ◽  
Pem Fuel Cells ◽  
Water Transfer ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Order Of Magnitude

Water management is of critical importance in a proton exchange membrane (PEM) fuel cell. Yet there are very limited studies of water transfer through the membrane and no data are available for water transfer due to individual mechanisms through the membrane electrode assembly (MEA) in an operational fuel cell. Thus it is the objective of this study to measure water transfer through the MEA due to different mechanisms through the membrane electrode assembly (MEA) of an operational PEM fuel cell. The three different mechanisms of water transfer, i.e., electro-osmotic drag, diffusion and hydraulic permeation were isolated by specially imposed boundary conditions. Therefore water transfer through the MEA due to each mechanism could be measured separately. In this study, all the data were collected in an actual assembled operational fuel cell, and some of the data were collected while the fuel cell was generating power. The measured results showed that water transfer due to hydraulic permeation, i.e. the pressure difference between the anode and cathode is at least an order of magnitude lower than those due to other two mechanisms. The data for water transfers due to electro-osmosis and diffusion through the MEA are in good agreement with some of the data and model predications in the literature for the membrane. The methodology used in this study is simple and can be easily adopted for in-situ water transfer measurement due to different mechanisms in actual PEM fuel cells without any cell modifications.

CO2 Electroreduction to C2 / C2+ Products Using Membrane Electrode Assembly

2020 ◽  
Vol MA2020-01 (39) ◽  
pp. 1739-1739
Author(s):  
Shariful Kibria Nabil ◽  
Md Golam Kibria
Keyword(s):  
Membrane Electrode Assembly ◽  
Membrane Electrode ◽  
Co2 Electroreduction

Integration of Micro Array Sensors in the MEA on Diagnosis of Micro Fuel Cells

2007 ◽  
Vol 364-366 ◽  
pp. 855-860
Author(s):  
Chi Yuan Lee ◽  
Shuo Jen Lee ◽  
Guan Wei Wu
Keyword(s):  
Fuel Cells ◽  
High Sensitivity ◽  
Membrane Electrode Assembly ◽  
Membrane Electrode ◽  
Humidity Sensors ◽  
Micro Electro Mechanical Systems ◽  
Mems Fabrication ◽  
Temperature And Humidity ◽  
Micro Array

The temperature and humidity conditions of a membrane electrode assembly (MEA) determine the performance of fuel cells. The volume of traditional temperature and humidity sensors is too large to allow them to be used to measure the distribution of temperature and humidity in the MEA of fuel cells. Measurements cannot necessarily be made where required. They measure only the temperature and humidity distribution outside the fuel cells and yield results with errors that exceed those of measurements made in MEA. Therefore, in this study, micro-electro-mechanical-systems (MEMS) fabrication technology was employed to fabricate an array of micro sensors to monitor in situ the temperature and humidity distributions within the MEA of fuel cells. In this investigation, an array of micro temperature and humidity sensors was made from gold on the MEA. The advantages of array micro gold temperature and humidity sensors are their small volume, which enable them to be placed on MEA and their high sensitivity and accuracy. The dimensions of the temperature and humidity sensors are 180μm × 180μm and 180μm × 220μm, respectively. The experiment involves temperatures from 30 to 100 °C. The resistance varied from 23.084 to 28.196 /. The experimental results reveal that the temperature is almost linearly related to the resistance and the accuracy and sensitivity are less than 0.3 °C and 3.2×10-3/°C, respectively. The humidity sensor showed that the capacitance changed from 15.76 to 17.95 pF, the relative humidity from 20 to 95 %RH, and the accuracy and sensitivity were less than 0.25 %RH and 0.03 pF/%RH.

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