Enhanced electrocatalytic CO formation from CO2 on nanostructured silver foam electrodes in ionic liquid/water mixtures (original) (raw)
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Electrodeposited AgCu Foam Catalysts for Enhanced Reduction of CO2 to CO
ACS Applied Materials & Interfaces, 2019
Selective electrochemical reduction of CO 2 is an emerging field which needs more active and stable catalysts for its practicability. In this work we have studied the influence of Ag metal incorporation into Cu dendritic structures on the product distribution and selectivity of CO 2 electroreduction. Bimetallic AgCu foams prepared by hydrogen bubble templated electrodeposition shift the potentials of CO production to more positive values compared to bulk silver. The presence of Ag during the electrodeposition significantly changed the size and the shape of the dendrites in the pore walls of AgCu foams compared to Cu foam. The CO adsorption characteristics are studied by operando Raman spectroscopy. In the presence of Ag, the maximum CO adsorption is observed at a more positive potential. As a result, an improved selectivity for CO is obtained for AgCu foam catalysts at lower overpotentials compared to Cu foam catalyst, evidencing a synergistic effect between the bimetallic components. We were successful in increasing the CO mass activity with respect to the total Ag amount. AgCu foams are found to retain the CO selectivity during long term operation, and with their easily scalable electrodeposition synthesis they possess high potential for industrial application.
Electrochemistry Communications, 2014
In this study, the electrochemical reduction of carbon dioxide (CO 2) was examined in a series of aqueous solutions of ionic liquids on metal (silver (Ag), copper, platinum and gold) catalyst cathode. The results indicated that Ag metal cathode in 1-butyl-3-methylimidazolium chloride (BMImCl) with 20 wt% water showed excellent synergy in electrochemical reduction of CO 2 to carbon monoxide (CO) with extremely high selectivity (>99%) and efficiency, and with stable area specific activity (ca. 2.4 mA•cm-2). The behavior of electrocatalytic reduction of CO 2 to CO on Ag electrode in ionic liquids (ILs) was examined by cyclic voltammogram. The study revealed that the chloride containing IL could be the most effective candidate for reduction of CO 2 to CO and for inhibiting the hydrogen evolution reaction probably due to the dominated water-anion and water-cation interactions in aqueous BMImCl.
Nano Energy, 2019
Bimetallic AgCu metal foams (15at% Ag, 85 at% Cu) have been synthesized by means of an additive-assisted electrodeposition process using the dynamic hydrogen bubble template approach. Ag and Cu remain fully phase-segregated in the as deposited bimetallic foam exhibiting a high degree of dispersion of pure nm-sized Ag domains embedded in the Cu matrix. An activation of this bimetallic material towards ethanol formation is achieved by thermal annealing of the as deposited foam under mild conditions (200° C for 12 h). Such annealing quantitatively transforms the Cu in the bimetallic system into a mixture of crystalline Cu2O and amorphous CuO whereas the Ag remains in its metallic state due to the thermal instability of Ag2O above temperatures of 180° C. The selective oxidation of Cu in the bimetallic Ag15Cu85 catalyst goes along with an enrichment of Cu oxides on the surface of the formed mixed AgCu xO foam. Both operando X-ray diffraction and operando Raman spectroscopy demonstrate, however, that the oxide reduction is completed before the electrochemical CO2 reduction sets in. The thus formed oxide-derived (OD) bimetallic Ag15Cu85 foam catalyst shows high selectivity towards alcohol formation with Faradaic efficiencies of FEEtOH = 33.7% and FEn-PrOH = 6.9% at-1.0 V and-0.9 V vs RHE, respectively. Extended electrolysis experiments (100 h) indicate a superior degradation resistance of the oxide-derived bimetallic catalyst which is ascribed to the effective suppression of the C1 hydrocarbon reaction pathway thus avoiding irreversible carbon contaminations appearing in particular during methane production.
Hydrogen Bubble Templated Metal Foams as Efficient Catalysts of CO 2 Electroreduction
ChemCatChem, 2020
The creation of open porous structures with an extremely high surface area is of great technological relevance. The electrochemical deposition of metal foams around co-generated hydrogen bubbles that act as templates for the deposition is a promising, cheap and simple approach to the fabrication of new electrocatalyst materials. Metal foams obtained by dynamic hydrogen bubble templating (DHBT) offer an intrinsically high electrical conductance with an open porous structure that enables the fast transport of gases and liquids. As an additional benefit, the confined space within the pores of DHBT metal foams may act as small reactors that can harbour reactions not possible at an open electrode interface. The number, distribution, and size of the pores can be fine-tuned by an appropriate choice of the electrolysis parameters so that metal foam catalysts prepared by the DHBT technique meet certain requirements. In this paper, we review the preparation of certain metal foams, and their applications as catalysts for the electrochemical reduction of CO2.
Rational Design of Silver Sulfide Nanowires for Efficient CO2 Electroreduction in Ionic Liquid
ACS Catalysis
S1. The specifications of chemicals and gases Silver nitrate (AgNO 3), potassium bicarbonate (> 99.99% trace metal basis) and isopropanol were all purchased from Fisher Scientific Company. Mercaptoacetic acid (C 2 H 4 O 2 S) was purchased from Alfa Aesar. 1-ethyl-3methylimidazoliumtetrafluoroborate (EMIM-BF 4 , > 98%, HPLC) and bulk Ag (25 µm) were purchased from Sigma Aldrich. Nafion perfluorinated ion-exchange resin solution (5 wt.% in mixture of lower aliphatic alcohol & H 2 O) was purchased from Sigma-Aldrich. Nafion ® N-117 membrane (0.18 mm thick) was purchased from Alfa Aesar; The glassy carbon electrode (GCE 10 mm) was purchased from AIDA Science Technology Company, China. Deionized water was taken from a Millipore Autopure system. All chemicals
Shape-Dependent Electrocatalytic Reduction of CO2 to CO on Triangular Silver Nanoplates
Journal of the American Chemical Society, 2017
Electrochemical reduction of CO2 (CO2RR) provides great potential for intermittent renewable energy storage. This study demonstrates a predominant shape-dependent electrocatalytic reduction of CO2 to CO on triangular silver nanoplates (Tri-Ag-NPs) in 0.1 M KHCO3. Compared with similarly sized Ag nanoparticles (SS-Ag-NPs) and bulk Ag, Tri-Ag-NPs exhibited an enhanced current density and significantly improved Faradaic efficiency (96.8%) and energy efficiency (61.7%), together with a considerable durability (7 days). Additionally, CO starts to be observed at an ultralow overpotential of 96 mV, further confirming the superiority of Tri-Ag-NPs as a catalyst for CO2RR toward CO formation. Density functional theory calculations reveal that the significantly enhanced electrocatalytic activity and selectivity at lowered overpotential originate from the shape-controlled structure. This not only provides the optimum edge-to-corner ratio but also dominates at the facet of Ag(100) where it requ...
Journal of Environmental Chemical Engineering, 2019
In this research, an electrochemical system, based on copper nanofoam accompanied by 1-butyl-3-methyl-imidazolium bromide (BMIMB) as the homogeneous co-catalyst for the electrochemical conversion of CO 2 at ambient pressure and temperature was developed. Although, there have been some efforts for utilization of copper nanofoam or imidazolium-based catalysts toward the electro-reduction of CO 2 , evaluation of both catalysts to take advantage of the potential synergic effect of their combination would be an interesting aspect. The electroreduction of CO 2 in a CO 2 saturated 0.1 M KHCO 3 electrolyte was optimized based on the highest CO 2 conversion efficiency in various conditions. The results show that the copper nanoporous foam, deposited for 45 s with the contribution of 40 mM BMIMB at-1.6 V vs. Ag/ AgCl would effectively reduce CO 2 and demonstrate a high CO 2 faradaic efficiency i.e. more than 46% improvement, compared to similar previously reported experiment. The results confirm the applicability of this experiment as a developed method for efficient CO 2 reduction. not only a quite high potential of −1.9 V vs NHE [9] but also an overpotential which is strongly dependent on the medium and electrode [10-14]. Recently, many researchers have vigorously inspected the
ACS Sustainable Chemistry & Engineering, 2018
Transition metals have been emerged as highly active catalysts for methanol oxidation reaction. 12 The development of low density metallic foams is exceedingly intriguing for various 13 applications. Here we report a systematic design of three dimensional (3D) porous 14 nanocomposites (foam) of transition metals like Cu and Ni with reduced graphite oxide (Cu-15 Ni@rGO) using simple self-propagation combustion method, where Cu-Ni foam structures are 16 wrapped around reduced graphite oxide. The field emission scanning electron microscopy 17 (FESEM) and transmission electron microscopy (TEM) show nanoporous structural morphology. 18 X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) show presence of different 19 oxidation states of metal ions and phase formation respectively. The electrochemical studies of 20 Cu-Ni@rGO nanocomposites exhibit interesting methanol electrooxidation properties with 21 exciting current density of 280 mA/cm 2 , which further retain 95% of their activity even after 600 22 s. In addition, these, Cu-Ni@rGO structures also reveal negligible poisoning effects during 23 methanol electrooxidation. More interestingly, Cu-Ni@rGO nanocomposites show remarkable 24 electrochemical CO oxidation to form CO 2 and the evidences support the Eley-Rideal 25 mechanism of CO oxidation, where presence of oxygen does not affect the oxidation process. 26
Journal of Colloid and Interface Science, 2022
Electrochemical CO 2 reduction represents a sustainable approach for the conversion of CO 2 into valuable fuels and chemicals. Here, we fabricated a series of composite nanomaterials through template-oriented polymerization of covalent organic frameworks (COFs) with isolated cobalt porphyrin units on amino-functionalized carbon nanotubes (CNTs) for efficiently electrocatalytic CO 2 reduction reaction (CO 2 RR). Compared with pure COFs, the hybrid form of ultrathin COF nanolayers wrapped on the conductive scaffold leads to distended current density and stable Faradaic efficiency (FE) for CO 2-to-CO conversion over a wide potential range. Specifically, the catalytic performances of the system can be finely optimized by the modification of the reticular structure with different functional groups. Our work gives a new strategy for the preparation of highly active and selective electrocatalysts for CO 2 RR.