scholarly journals Electrochemical Reduction of CO2: Overcoming Chemical Inertness at Ambient Conditions

Electrochem ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 56-59
Author(s):  
Ana Cristina Perez ◽  
Manuel Antonio Diaz-Perez ◽  
Juan Carlos Serrano-Ruiz
Keyword(s):  
Electrochemical Reduction ◽  
Active Sites ◽  
Storage System ◽  
Reduction Process ◽  
Electrochemical Reactor ◽  
Great Promise ◽  
Ambient Conditions ◽  
Faradaic Efficiency ◽  
Fine Control ◽  
Reduction Of Co2

Electroreduction allows for the transformation of a chemically inert molecule such as CO2 into a wide variety of useful carbon products. Unlike other approaches operating at higher temperatures, electrochemical reduction holds great promise since it achieves reduction under ambient conditions, thereby providing more control over the reaction selectivity. By controlling basic parameters such as the potential and the composition of the electrode, CO2 can be transformed into a variety of products including carbon monoxide, syngas (CO/H2), methane, and methanol. This reduction process takes place without external hydrogen, since water can be used as a source of both electrons and protons. Furthermore, this technology, when combined with renewable wind- or solar-derived electricity, has the potential to serve as a storage system for excess electricity. Despite these advantages, a number of challenges need to be overcome before reaching commercialization. New (and cheaper) electrocatalyst formulations with high faradaic selectivities are required. Impressive progress has been made on carbon-doped materials, which, in certain cases, have outperformed expensive noble metal-based materials. Research is also needed on new electrochemical reactor configurations able to overcome kinetic/mass transport limitations, which are crucial to reduce overpotentials. Fine control over the nature of the active sites and the reaction conditions is important to avoid parasitic reactions such as the hydrogen evolution reaction (HER), and therefore increases the faradaic efficiency towards the desired products.

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 Synthesis of Valeric Acid by Selective Electrocatalytic Hydrogenation of Biomass-Derived Levulinic Acid

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 692
Author(s):  
Yan Du ◽  
Xiao Chen ◽  
Ji Qi ◽  
Pan Wang ◽  
Changhai Liang
Keyword(s):  
Levulinic Acid ◽  
Active Sites ◽  
Valeric Acid ◽  
Future Research ◽  
Adsorbed Hydrogen ◽  
Electrocatalytic Hydrogenation ◽  
Ambient Conditions ◽  
Metallic Lead ◽  
Faradaic Efficiency ◽  
Lead Electrode

The electrocatalytic hydrogenation (ECH) of biomass-derived levulinic acid (LA) is a promising strategy to synthetize fine chemicals under ambient conditions by replacing the thermocatalytic hydrogenation at high temperature and high pressure. Herein, various metallic electrodes were investigated in the ECH of LA in a H-type divided cell. The effects of potential, electrolyte concentration, reactant concentration, and temperature on catalytic performance and Faradaic efficiency were systematically explored. The high conversion of LA (93%) and excellent “apparent” selectivity to valeric acid (VA) (94%) with a Faradaic efficiency of 46% can be achieved over a metallic lead electrode in 0.5 M H2SO4 electrolyte containing 0.2 M LA at an applied voltage of −1.8 V (vs. Ag/AgCl) for 4 h. The combination of adsorbed LA and adsorbed hydrogen (Hads) on the surface of the metallic lead electrode is key to the formation of VA. Interestingly, the reaction performance did not change significantly after eight cycles, while the surface of the metallic lead cathode became rough, which may expose more active sites for the ECH of LA to VA. However, there was some degree of corrosion for the metallic lead cathode in this strong acid environment. Therefore, it is necessary to improve the leaching-resistance of the cathode for the ECH of LA in future research.

scholarly journals CuZnAl-Oxide Nanopyramidal Mesoporous Materials for the Electrocatalytic CO2 Reduction to Syngas: Tuning of H2/CO Ratio

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3052
Author(s):  
Hilmar Guzmán ◽  
Daniela Roldán ◽  
Adriano Sacco ◽  
Micaela Castellino ◽  
Marco Fontana ◽  
...  
Keyword(s):  
Noble Metals ◽  
Co2 Reduction ◽  
Reduction Process ◽  
Mesoporous Structure ◽  
Catalytic Performance ◽  
H2 Production ◽  
Ambient Conditions ◽  
Transfer Resistance ◽  
Faradaic Efficiency ◽  
Co2 Electroreduction

Inspired by the knowledge of the thermocatalytic CO2 reduction process, novel nanocrystalline CuZnAl-oxide based catalysts with pyramidal mesoporous structures are here proposed for the CO2 electrochemical reduction under ambient conditions. The XPS analyses revealed that the co-presence of ZnO and Al2O3 into the Cu-based catalyst stabilize the CuO crystalline structure and introduce basic sites on the ternary as-synthesized catalyst. In contrast, the as-prepared CuZn- and Cu-based materials contain a higher amount of superficial Cu0 and Cu1+ species. The CuZnAl-catalyst exhibited enhanced catalytic performance for the CO and H2 production, reaching a Faradaic efficiency (FE) towards syngas of almost 95% at −0.89 V vs. RHE and a remarkable current density of up to 90 mA cm−2 for the CO2 reduction at −2.4 V vs. RHE. The physico-chemical characterizations confirmed that the pyramidal mesoporous structure of this material, which is constituted by a high pore volume and small CuO crystals, plays a fundamental role in its low diffusional mass-transfer resistance. The CO-productivity on the CuZnAl-catalyst increased at more negative applied potentials, leading to the production of syngas with a tunable H2/CO ratio (from 2 to 7), depending on the applied potential. These results pave the way to substitute state-of-the-art noble metals (e.g., Ag, Au) with this abundant and cost-effective catalyst to produce syngas. Moreover, the post-reaction analyses demonstrated the stabilization of Cu2O species, avoiding its complete reduction to Cu0 under the CO2 electroreduction conditions.

Facile, cost-effective plasma synthesis of self-supportive FeSx on Fe foam for efficient electrochemical reduction of N2 under ambient conditions

2019 ◽  
Vol 7 (34) ◽  
pp. 19977-19983 ◽  
Author(s):  
Wei Xiong ◽  
Zheng Guo ◽  
Shijun Zhao ◽  
Qian Wang ◽  
Qiyong Xu ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Electrochemical Reduction ◽  
Production Rate ◽  
Low Cost ◽  
Cost Effective ◽  
Plasma Synthesis ◽  
Ambient Conditions ◽  
Faradaic Efficiency

A non-precious, self-supportive FeSx NRR electrocatalyst was synthesized by a simple H2S-plasma treatment on low-cost Fe foam, which shows a remarkable NH3 production rate of 4.13 × 10−10 mol s−1 cm−2 and a high faradaic efficiency of 17.6%.

scholarly journals Electrochemical reduction of CO2 to ethylene on Cu/CuxO-GO composites in aqueous solution

RSC Advances ◽  
2020 ◽  
Vol 10 (30) ◽  
pp. 17572-17581
Author(s):  
Nusrat Rashid ◽  
Mohsin Ahmad Bhat ◽  
U. K. Goutam ◽  
Pravin Popinand Ingole
Keyword(s):  
Aqueous Solution ◽  
Graphene Oxide ◽  
Electrochemical Reduction ◽  
Conversion Rate ◽  
Faradaic Efficiency ◽  
Reduction Of Co2

Herein, we present fabrication of graphene oxide supported Cu/CuxO nano-electrodeposits which efficiently and selectively can electroreduce CO2 into ethylene with a faradaic efficiency of 34% and conversion rate of 194 mmol g−1 h−1 at −0.985 V vs. RHE.

scholarly journals Low-Overpotential Electrochemical Reduction of CO2 to Formic Acid on Surface-Modified Doped Tin Oxide Pellets

2019 ◽  
Author(s):  
Emmanuel Abdul ◽  
Jason Pitts ◽  
Deepak Rajput ◽  
Shankar Rananavare
Keyword(s):  
Formic Acid ◽  
Electrochemical Reduction ◽  
Current Density ◽  
Tin Oxide ◽  
Aqueous Media ◽  
Oxide Nanoparticles ◽  
Faradaic Efficiency ◽  
Electrode Potentials ◽  
Tin Oxide Nanoparticles ◽  
Reduction Of Co2

Gas sensors fabricated with antimony doped tin oxide (ATO) nanomaterials exhibit remarkable sensitivity for detecting oxidizing and reducing gases. This study highlights the enhanced selectivity and stability of the porous ATO nanomaterial electrode made for electrochemical reduction of CO2 in aqueous media. During electrochemical reduction, these electrodes prepared from compressed powders tend to crumble within a few hours in aqueous media. To overcome this electrode disintegration effect, we modified the surface of the doped tin-Oxide nanoparticles with Nafion and a dipodal silane (1,2-Bis(triethoxysilyl)ethane). The electrode characterization studies include Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS). Scanning electron microscopic investigation of electrode surface morphology and roughness before and after electrochemical CO2 reduction for derivatized and underivatized electrode revealed lower surface roughness for former than the latter.The derivatized electrodes allowed CO2 electrochemical reduction at low overpotentials and high current density without any electrode crumbling over more than 24 hours of continuous operation. Formate/formic acid and methanol were the major products of reduction at electrode potentials ranging from -0.4 to -1.0V vs. RHE in the CO2 saturated 0.1M KHCO3 electrolyte. Higher current density and Faradaic Efficiency of formic acid was observed when compared to planar tin electrode materials and tin oxide nanoparticles deposited on FTO glass.

scholarly journals Arc Plasma Deposited Copper and Gold Nanoparticles on FTO Substrate for Electrochemical Reduction of CO2

2019 ◽  
Vol 3 (1) ◽  
Keyword(s):  
Gold Nanoparticles ◽  
Formic Acid ◽  
Electrochemical Reduction ◽  
High Efficiency ◽  
Plasma Deposition ◽  
Arc Plasma ◽  
Faradaic Efficiency ◽  
Electro Deposition ◽  
Electro Catalysis ◽  
Reduction Of Co2

A composite of copper and gold nanoparticles was deposited using arc plasma deposition on the conductive FTO substrate for the electrochemical reduction of CO2 . The use of arc plasma deposition system allows the nanoparticles to be implanted onto the substrate as opposed to the commonly used methods of vacuum deposition or electro deposition. This unique structure reduced the CO2 to produce formic acid with up to 60% faradaic efficiency. Copper and gold nanoparticles have never previously been reported to produce formic acid with such high efficiency, suggesting that the co-deposition technique of implanted nanoparticles can provide an interesting future avenue in the field of electrochemical reduction of CO2 . The surface analysis of the electrodes is presented here along with potential dependent faradaic efficiency of the electro catalysis.

scholarly journals Ordered Mesoporous Carbon as a Support of Pd Catalysts for CO2 Electrochemical Reduction

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 912
Author(s):  
Sara Pérez-Rodríguez ◽  
Elena Pastor ◽  
María Jesús Lázaro
Keyword(s):  
Electrochemical Reduction ◽  
Active Sites ◽  
Pd Nanoparticles ◽  
Catalyst Supports ◽  
Mass Ratio ◽  
Pd Catalysts ◽  
Ordered Mesoporous Carbons ◽  
Ordered Mesoporous ◽  
Reduction Of Co2 ◽  
Average Size

Ordered mesoporous carbons (OMCs) have been used as catalyst supports of Pd nanoparticles for the electrochemical reduction of CO2 in 0.1 M KHCO3. OMC with tunable porosity and morphology were obtained by the hard-template approach using synthesized SBA-15 templates. SBA-15 materials were prepared using a mass ratio of the silica precursor (TEOS) and the surfactant (P123) of 2 or 5. After removing silica particles by a purification treatment with NaOH-ethanol or HF, different OMCs were obtained, with a developed porosity (up to 1050 m2 g−1) and ordered 2D hexagonal mesostructure (p6 mm). An increase in the TEOS/P123 ratio as well as the treatment with HF resulted in a decrease in the structural ordering of the materials. Pd nanoparticles with an average size of around 3 nm were deposited on the OMC. However, larger nanoparticles were also observed, especially for the materials obtained using a mass ratio TEOS/P123 of 5. Despite these differences, electrochemical experiments showed that CO2 was successfully reduced to other species (mainly COad) for all Pd/OMC electrocatalysts. These reduced species were adsorbed on Pd active sites, inhibiting the hydrogen evolution reaction.

scholarly journals Photoelectrochemical Reduction of CO2 to Syngas by Reduced Ag Catalysts on Si Photocathodes

2020 ◽  
Vol 10 (10) ◽  
pp. 3487 ◽  
Author(s):  
Changyeon Kim ◽  
Seokhoon Choi ◽  
Min-Ju Choi ◽  
Sol A Lee ◽  
Sang Hyun Ahn ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Co2 Reduction ◽  
Reduction Reaction ◽  
Hydrogen Electrode ◽  
Faradaic Efficiency ◽  
Onset Potential ◽  
Reduction Of Co2 ◽  
Co2 Reduction Reaction ◽  
Ag Catalysts

The photoelectrochemical reduction of CO2 to syngas that is used for many practical applications has been emerging as a promising technique to relieve the increase of CO2 in the atmosphere. Si has been considered to be one of the most promising materials for photoelectrodes, but the integration of electrocatalysts is essential for the photoelectrochemical reduction of CO2 using Si. We report an enhancement of catalytic activity for CO2 reduction reaction by Ag catalysts of tuned morphology, active sites, and electronic structure through reducing anodic treatment. Our proposed photocathode structure, a SiO2 patterned p-Si photocathode with these reduced Ag catalysts, that was fabricated using electron-beam deposition and electrodeposition methods, provides a low onset-potential of −0.16 V vs. the reversible hydrogen electrode (RHE), a large saturated photocurrent density of −9 mA/cm2 at −1.23 V vs. RHE, and faradaic efficiency for CO of 47% at −0.6 V vs. RHE. This photocathode can produce syngas in the ratio from 1:1 to 1:3, which is an appropriate proportion for practical application. This work presents a new approach for designing photocathodes with a balanced catalytic activity and light absorption to improve the photoelectrochemical application for not only CO2 reduction reaction, but also water splitting or N2 reduction reaction.

scholarly journals Electrochemical Reduction of CO2 to Formate on Easily Prepared Carbon-Supported Bi Nanoparticles

Molecules ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 2032 ◽  
Author(s):  
Beatriz Ávila-Bolívar ◽  
Leticia García-Cruz ◽  
Vicente Montiel ◽  
José Solla-Gullón
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Reduction ◽  
Carbon Paper ◽  
Faradaic Efficiency ◽  
X Ray ◽  
Bismuth Nanoparticles ◽  
Electrode Potentials ◽  
Co2 Electroreduction ◽  
Reduction Of Co2 ◽  
Bi Nanoparticles

Herein, the electrochemical reduction of CO2 to formate on carbon-supported bismuth nanoparticles is reported. Carbon-supported Bi nanoparticles (about 10 nm in size) were synthesized using a simple, fast and scalable approach performed under room conditions. The so-prepared Bi electrocatalyst was characterized by different physicochemical techniques, including transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction and subsequently air-brushed on a carbon paper to prepare electrodes. These electrodes were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy and also by cyclic voltammetry. Finally, CO2 electroreduction electrolyses were performed at different electrode potentials for 3 h. At the optimal electrode potential (−1.6 V vs AgCl/Ag), the concentration of formate was about 77 mM with a faradaic efficiency of 93 ± 2.5%. A 100% faradaic efficiency was found at a lower potential (−1.5 V vs AgCl/Ag) with a formate concentration of about 55 mM. In terms of stability, we observed that after about 70 h (in 3 h electrolysis experiments at different potentials), the electrode deactivates due to the gradual loss of metal as shown by SEM/EDX analyses of the deactivated electrodes.

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