scholarly journals Improved electrochemical conversion of CO2 to multicarbon products by using molecular doping

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Huali Wu ◽  
Ji Li ◽  
Kun Qi ◽  
Yang Zhang ◽  
Eddy Petit ◽  
...  
Keyword(s):  
Reaction Pathway ◽  
Copper Catalyst ◽  
Reduction Reaction ◽  
Reaction Products ◽  
Faradaic Efficiency ◽  
Electrochemical Conversion ◽  
Cell Energy ◽  
Molecular Doping ◽  
X Ray Absorption ◽  
Carbon Economy

AbstractThe conversion of CO2 into desirable multicarbon products via the electrochemical reduction reaction holds promise to achieve a circular carbon economy. Here, we report a strategy in which we modify the surface of bimetallic silver-copper catalyst with aromatic heterocycles such as thiadiazole and triazole derivatives to increase the conversion of CO2 into hydrocarbon molecules. By combining operando Raman and X-ray absorption spectroscopy with electrocatalytic measurements and analysis of the reaction products, we identified that the electron withdrawing nature of functional groups orients the reaction pathway towards the production of C2+ species (ethanol and ethylene) and enhances the reaction rate on the surface of the catalyst by adjusting the electronic state of surface copper atoms. As a result, we achieve a high Faradaic efficiency for the C2+ formation of ≈80% and full-cell energy efficiency of 20.3% with a specific current density of 261.4 mA cm−2 for C2+ products.

scholarly journals Improved electrochemical conversion of CO2 to multicarbon products by using molecular doping

2021 ◽  
Author(s):  
Huali WU ◽  
Ji Li ◽  
Kun Qi ◽  
Yang Zhang ◽  
Eddy Petit ◽  
...  
Keyword(s):  
High Efficiency ◽  
Reaction Pathway ◽  
Reaction Rates ◽  
Reduction Reaction ◽  
Reaction Products ◽  
Faradaic Efficiency ◽  
Cu Catalyst ◽  
Cell Energy ◽  
Current Densities ◽  
Novel Strategy

Abstract The conversion of CO2 into desirable multicarbon products such as ethylene and ethanol via the carbon dioxide reduction reaction (CO2RR) hold promise to achieve a circular carbon economy. The develop of such a technology is currently hampered by the lack of catalysts, which can drive the reaction at industrially relevant current densities with high efficiency and selectivity. Here, we report a novel strategy for increasing the conversion of CO2 into hydrocarbon molecules with two or more carbon atoms (C2+) by modifying the surface of bimetallic silver-copper (Ag-Cu) catalyst with aromatic heterocycles such as thiadiazole and triazole derivatives. By combining operando Raman and X-ray absorption spectroscopy with electrocatalytic measurements and analysis of the reaction products, we identified that the electron withdrawing nature of functional groups orients the reaction pathway towards the production of C2+ species such as ethanol and ethylene and enhances the reaction rates on the surface of the catalyst. As a result, we achieve a maximum Faradaic efficiency for the formation of C2+ of ≈ 80% and full-cell energy efficiency of 20.3% with a specific current density of 261.4 mA cm-2 for C2+ using functionalized Ag-Cu electrodes, compared to only 33.8% and 70.6 mA cm-2 for the pristine Ag-Cu electrodes. We anticipate that our strategy can further be extended in order to improve the selectivity of the reaction towards the production of specific multicarbon molecules.

Electrochemical and spectroscopic characterization of a dicobalt macrocyclic Pacman complex in the catalysis of the oxygen reduction reaction in acid media

2013 ◽  
Vol 17 (04) ◽  
pp. 252-258 ◽  
Author(s):  
Qinggang He ◽  
Xiao Cheng ◽  
Ying Wang ◽  
Ruimin Qiao ◽  
Wanli Yang ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reaction Pathway ◽  
Spectroscopic Characterization ◽  
Reduction Reaction ◽  
Acid Media ◽  
Crystal Fields ◽  
Mononuclear Cobalt ◽  
X Ray Absorption

The dicobalt complex [ Co2(L2) ] of a Schiff-base pyrrole macrocycle adopts a Pacman structure in solution and the solid state and shows much greater catalytic activity and selectivity for the four-electron oxygen reduction reaction (ORR) than the mononuclear cobalt phthalocyanine (CoPc) counterpart. Soft X-ray absorption spectroscopy (XAS) shows that the Co center in Co2(L2) is of the same valence as mononuclear CoPc . However, the former complex shows higher unoccupied Co 3d density which is believed to be beneficial for electron transfers. Furthermore, the XAS data suggests that the crystal fields for Co2(L2) and CoPc are different, and that an interaction remains between two Co atoms in Co2(L2) . DFT calculations imply that the sterically hindered, cofacial structure of the dicobalt complex is critical for the operation of the four-electron reaction pathway during the ORR.

Zr-doped α-FeOOH with High Faradaic Efficiency for Electrochemical Nitrogen Reduction Reaction

2021 ◽  
pp. 150801
Author(s):  
Jiabin Tan ◽  
Xiaobo H ◽  
Fengxiang Yin ◽  
Xin Liang ◽  
Guoru Li ◽  
...  
Keyword(s):  
Reduction Reaction ◽  
Faradaic Efficiency ◽  
Nitrogen Reduction

scholarly journals Efficient electrocatalytic nitrogen reduction to ammonia with aqueous silver nanodots

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Wenyi Li ◽  
Ke Li ◽  
Yixing Ye ◽  
Shengbo Zhang ◽  
Yanyan Liu ◽  
...  
Keyword(s):  
Active Sites ◽  
Theoretical Calculations ◽  
Current Collector ◽  
Electrochemical Reactor ◽  
Reduction Reaction ◽  
Solution Ph ◽  
Faradaic Efficiency ◽  
Yield Rate ◽  
Silver Nanodots ◽  
Ti Mesh

AbstractThe electrocatalytic nitrogen (N2) reduction reaction (NRR) relies on the development of highly efficient electrocatalysts and electrocatalysis systems. Herein, we report a non-loading electrocatalysis system, where the electrocatalysts are dispersed in aqueous solution rather than loading them on electrode substrates. The system consists of aqueous Ag nanodots (AgNDs) as the catalyst and metallic titanium (Ti) mesh as the current collector for electrocatalytic NRR. The as-synthesized AgNDs, homogeneously dispersed in 0.1 M Na2SO4 solution (pH = 10.5), can achieve an NH3 yield rate of 600.4 ± 23.0 μg h−1 mgAg−1 with a faradaic efficiency (FE) of 10.1 ± 0.7% at −0.25 V (vs. RHE). The FE can be further improved to be 20.1 ± 0.9% at the same potential by using Ti mesh modified with oxygen vacancy-rich TiO2 nanosheets as the current collector. Utilizing the aqueous AgNDs catalyst, a Ti plate based two-electrode configured flow-type electrochemical reactor was developed to achieve an NH3 yield rate of 804.5 ± 30.6 μg h−1 mgAg−1 with a FE of 8.2 ± 0.5% at a voltage of −1.8 V. The designed non-loading electrocatalysis system takes full advantage of the AgNDs’ active sites for N2 adsorption and activation, following an alternative hydrogenation mechanism revealed by theoretical calculations.

scholarly journals Quasi-graphitic carbon shell-induced Cu confinement promotes electrocatalytic CO2 reduction toward C2+ products

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ji-Yong Kim ◽  
Deokgi Hong ◽  
Jae-Chan Lee ◽  
Hyoung Gyun Kim ◽  
Sungwoo Lee ◽  
...  
Keyword(s):  
High Efficiency ◽  
Co2 Reduction ◽  
Value Added ◽  
Material Design ◽  
Catalyst System ◽  
Critical Issue ◽  
Reduction Reaction ◽  
Catalyst Design ◽  
Design Strategies ◽  
Faradaic Efficiency

AbstractFor steady electroconversion to value-added chemical products with high efficiency, electrocatalyst reconstruction during electrochemical reactions is a critical issue in catalyst design strategies. Here, we report a reconstruction-immunized catalyst system in which Cu nanoparticles are protected by a quasi-graphitic C shell. This C shell epitaxially grew on Cu with quasi-graphitic bonding via a gas–solid reaction governed by the CO (g) - CO2 (g) - C (s) equilibrium. The quasi-graphitic C shell-coated Cu was stable during the CO2 reduction reaction and provided a platform for rational material design. C2+ product selectivity could be additionally improved by doping p-block elements. These elements modulated the electronic structure of the Cu surface and its binding properties, which can affect the intermediate binding and CO dimerization barrier. B-modified Cu attained a 68.1% Faradaic efficiency for C2H4 at −0.55 V (vs RHE) and a C2H4 cathodic power conversion efficiency of 44.0%. In the case of N-modified Cu, an improved C2+ selectivity of 82.3% at a partial current density of 329.2 mA/cm2 was acquired. Quasi-graphitic C shells, which enable surface stabilization and inner element doping, can realize stable CO2-to-C2H4 conversion over 180 h and allow practical application of electrocatalysts for renewable energy conversion.

Switching the Oxygen Reduction Reaction Pathway via Tailoring the Electronic Structure of FeN4/C Catalysts

ACS Catalysis ◽  
2021 ◽  
pp. 13020-13027
Author(s):  
Yanping Zhu ◽  
Jiejie Li ◽  
Yubin Chen ◽  
Jian Zou ◽  
Qingqing Cheng ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reaction Pathway ◽  
Reduction Reaction

Efficient N2 Reduction with VS2 Electrocatalyst: Identifying the Active Sites and Unraveling the Reaction Pathway

2021 ◽  
Author(s):  
Liang Zhao ◽  
Rui Zhao ◽  
Yixiang Zhou ◽  
Xiaoxuan Wang ◽  
Xinyue Chi ◽  
...  
Keyword(s):  
Active Sites ◽  
Reaction Pathway ◽  
Reduction Reaction ◽  
Sustainable Production ◽  
Nitrogen Reduction

Electrochemical nitrogen reduction reaction (NRR) is an effective method for sustainable production of NH3. However, a robust NRR electrocatalyst is predominantly required in order to active the inert N2 molecule....

One-Step Simultaneous Differential Scanning Calorimetry-FTIR Microspectroscopy to Quickly Detect Continuous Pathways in the Solid-State Glucose/Asparagine Maillard Reaction

2013 ◽  
Vol 96 (6) ◽  
pp. 1362-1364 ◽  
Author(s):  
Deng-Fwu Hwang ◽  
Tzu-Feng Hsieh ◽  
Shan-Yang Lin
Keyword(s):  
Differential Scanning Calorimetry ◽  
Solid State ◽  
Maillard Reaction ◽  
Reaction Pathway ◽  
Molar Ratio ◽  
Maillard Reaction Products ◽  
Reaction Products ◽  
Scanning Calorimetry ◽  
Ftir Microspectroscopy ◽  
Amadori Product

Abstract The stepwise reaction pathway of the solid-state Maillard reaction between glucose (Glc) and asparagine (Asn) was investigated using simultaneous differential scanning calorimetry (DSC)-FTIR microspectroscopy. The color change and FTIR spectra of Glc-Asn physical mixtures (molar ratio = 1:1) preheated to different temperatures followed by cooling were also examined. The successive reaction products such as Schiff base intermediate, Amadori product, and decarboxylated Amadori product in the solid-state Glc-Asn Maillard reaction were first simultaneously evidenced by this unique DSC-FTIR microspectroscopy. The color changed from white to yellow-brown to dark brown, and appearance of new IR peaks confirmed the formation of Maillard reaction products. The present study clearly indicates that this unique DSC-FTIR technique not only accelerates but also detects precursors and products of the Maillard reaction in real time.

Sign in / Sign up

Export Citation Format

Share Document