Guiding the Catalytic Properties of Copper for Electrochemical CO2 Reduction by Metal Atom Decoration

Author(s):  
Yusaku F. Nishimura ◽  
Hong-Jie Peng ◽  
Stephanie Nitopi ◽  
Michal Bajdich ◽  
Lei Wang ◽  
...  
2017 ◽  
Vol 198 ◽  
pp. 409-418 ◽  
Author(s):  
Hohyun Jeong ◽  
Myung Jong Kang ◽  
Hyeyeong Jung ◽  
Young Soo Kang

Pyridine molecules have been used as a catalyst to reduce the activation energy of the CO2 reduction reaction. It has been reported that CO2 is reduced by pyridine catalysts at low overpotential around −0.58 V vs. SCE. Poly(4-vinylpyridine), which has pyridine functional groups shows similar catalytic properties to reduce CO2 at low overpotential like pyridinium catalysts. Different thickness of P(4-VP) coated Pt electrodes were analyzed to determine the catalytic properties for CO2 reduction. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy methods showed the catalytic CO2 reduction properties of a P(4-VP)/Pt electrode. Thin P(4-VP)/Pt film showed a low current density of −0.16 mA cm−2 under CO2 atmosphere and the current density reached −0.45 mA cm−2 with increase of the P(4-VP) thickness. The increase of current density was explained by an increased surface concentration of adsorbed pyridinium groups of the thick P(4-VP) layer. Nyquist plots also showed decrease of impedance with increase of the P(4-VP) layer indicating fast charge transfer between Pt and the P(4-VP) layer due to the increase of hybrid ionic complex formation on the Pt surface. However, charge transfer is restricted when the P(4-VP) layer becomes more thick because of slowed protonation of pyridine groups adjacent to the Pt surface due to the suppressed permeability of electrolyte solution into the PVP membrane. This electrochemical observation provides a new aspect of P(4-VP) polymer for CO2 reduction.


ACS Catalysis ◽  
2020 ◽  
Vol 10 (17) ◽  
pp. 10068-10095 ◽  
Author(s):  
Tu N. Nguyen ◽  
Mahdi Salehi ◽  
Quyet Van Le ◽  
Ali Seifitokaldani ◽  
Cao Thang Dinh

Author(s):  
Peter T. Smith ◽  
Sophia Weng ◽  
Christopher Chang

We present a bioinspired strategy for enhancing electrochemical carbon dioxide reduction catalysis by cooperative use of base-metal molecular catalysts with intermolecular second-sphere redox mediators that facilitate both electron and proton transfer. Functional synthetic mimics of the biological redox cofactor NADH, which are electrochemically stable and are capable of mediating both electron and proton transfer, can enhance the activity of an iron porphyrin catalyst for electrochemical reduction of CO<sub>2</sub> to CO, achieving a 13-fold rate improvement without altering the intrinsic high selectivity of this catalyst platform for CO<sub>2</sub> versus proton reduction. Evaluation of a systematic series of NADH analogs and redox-inactive control additives with varying proton and electron reservoir properties reveals that both electron and proton transfer contribute to the observed catalytic enhancements. This work establishes that second-sphere dual control of electron and proton inventories is a viable design strategy for developing more effective electrocatalysts for CO<sub>2</sub> reduction, providing a starting point for broader applications of this approach to other multi-electron, multi-proton transformations.


2020 ◽  
Vol 43 ◽  
pp. 154-160 ◽  
Author(s):  
Xianglong Lu ◽  
Tianshui Yu ◽  
Hailing Wang ◽  
Lihua Qian ◽  
Ruichun Luo ◽  
...  

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 482
Author(s):  
Hilmar Guzmán ◽  
Federica Zammillo ◽  
Daniela Roldán ◽  
Camilla Galletti ◽  
Nunzio Russo ◽  
...  

Electrochemical CO2 reduction is a promising carbon capture and utilisation technology. Herein, a continuous flow gas diffusion electrode (GDE)-cell configuration has been studied to convert CO2 via electrochemical reduction under atmospheric conditions. To this purpose, Cu-based electrocatalysts immobilised on a porous and conductive GDE have been tested. Many system variables have been evaluated to find the most promising conditions able to lead to increased production of CO2 reduction liquid products, specifically: applied potentials, catalyst loading, Nafion content, KHCO3 electrolyte concentration, and the presence of metal oxides, like ZnO or/and Al2O3. In particular, the CO productivity increased at the lowest Nafion content of 15%, leading to syngas with an H2/CO ratio of ~1. Meanwhile, at the highest Nafion content (45%), C2+ products formation has been increased, and the CO selectivity has been decreased by 80%. The reported results revealed that the liquid crossover through the GDE highly impacts CO2 diffusion to the catalyst active sites, thus reducing the CO2 conversion efficiency. Through mathematical modelling, it has been confirmed that the increase of the local pH, coupled to the electrode-wetting, promotes the formation of bicarbonate species that deactivate the catalysts surface, hindering the mechanisms for the C2+ liquid products generation. These results want to shine the spotlight on kinetics and transport limitations, shifting the focus from catalytic activity of materials to other involved factors.


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