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Author |
Van den Hoek, J.; Daems, N.; Arnouts, S.; Hoekx, S.; Bals, S.; Breugelmans, T. |
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Title |
Improving stability of CO₂ electroreduction by incorporating Ag NPs in N-doped ordered mesoporous carbon structures |
Type |
A1 Journal article |
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Year  |
2024 |
Publication |
ACS applied materials and interfaces |
Abbreviated Journal |
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Volume |
16 |
Issue |
6 |
Pages |
6931-6947 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT) |
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Abstract |
The electroreduction of carbon dioxide (eCO2RR) to CO using Ag nanoparticles as an electrocatalyst is promising as an industrial carbon capture and utilization (CCU) technique to mitigate CO2 emissions. Nevertheless, the long-term stability of these Ag nanoparticles has been insufficient despite initial high Faradaic efficiencies and/or partial current densities. To improve the stability, we evaluated an up-scalable and easily tunable synthesis route to deposit low-weight percentages of Ag nanoparticles (NPs) on and into the framework of a nitrogen-doped ordered mesoporous carbon (NOMC) structure. By exploiting this so-called nanoparticle confinement strategy, the nanoparticle mobility under operation is strongly reduced. As a result, particle detachment and agglomeration, two of the most pronounced electrocatalytic degradation mechanisms, are (partially) blocked and catalyst durability is improved. Several synthesis parameters, such as the anchoring agent, the weight percentage of Ag NPs, and the type of carbonaceous support material, were modified in a controlled manner to evaluate their respective impact on the overall electrochemical performance, with a strong emphasis on operational stability. The resulting powders were evaluated through electrochemical and physicochemical characterization methods, including X-ray diffraction (XRD), N2-physisorption, Inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM), SEM-energy-dispersive X-ray spectroscopy (SEM-EDS), high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), STEM-EDS, electron tomography, and X-ray photoelectron spectroscopy (XPS). The optimized Ag/soft-NOMC catalysts showed both a promising selectivity (∼80%) and stability compared with commercial Ag NPs while decreasing the loading of the transition metal by more than 50%. The stability of both the 5 and 10 wt % Ag/soft-NOMC catalysts showed considerable improvements by anchoring the Ag NPs on and into a NOMC framework, resulting in a 267% improvement in CO selectivity after 72 h (despite initial losses) compared to commercial Ag NPs. These results demonstrate the promising strategy of anchoring Ag NPs to improve the CO selectivity during prolonged experiments due to the reduced mobility of the Ag NPs and thus enhanced stability. |
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Wos |
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Publication Date |
2023-12-21 |
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ISSN |
1944-8244 |
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UA library record |
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no |
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Call Number |
UA @ admin @ c:irua:202309 |
Serial |
9045 |
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Author |
Van Daele, S.; Hintjens, L.; Hoekx, S.; Bohlen, B.; Neukermans, S.; Daems, N.; Hereijgers, J.; Breugelmans, T. |
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Title |
How flue gas impurities affect the electrochemical reduction of CO₂ to CO and formate |
Type |
A1 Journal article |
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Year |
2024 |
Publication |
Applied catalysis : B : environmental |
Abbreviated Journal |
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Volume |
341 |
Issue |
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Pages |
123345-10 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Applied Electrochemistry & Catalysis (ELCAT); Electron microscopy for materials research (EMAT) |
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Abstract |
The electrochemical CO2 reduction offers a promising solution to convert waste CO2 into valuable products like CO and formate. However, CO2 capture and purification remains an energy intensive process and therefore the direct usage of industrially available waste CO2 streams containing SO2, NO and O2 impurities becomes more interesting. This work demonstrates an efficient (Faradaic efficiency > 90 %) and stable performance over 20 h with 200 ppm SO2 or NO in the feed gas stream. However, the addition of 1 % O2 to the CO2 feed causes a significant drop in Faradaic efficiency to C-products due to the competitive oxygen reduction reaction. A potential mitigation strategy is to operate at higher total current density to firstly reduce most O2 and achieve sufficient product output from CO2 reduction. These results aid in understanding the impact of flue gas impurities during CO2 electrolysis which is crucial for potentially bypassing the CO2 purification step. |
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001102999000001 |
Publication Date |
2023-10-01 |
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ISSN |
0926-3373 |
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UA library record; WoS full record |
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no |
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Call Number |
UA @ admin @ c:irua:199490 |
Serial |
9044 |
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Author |
Moggia, G.; Hoekx, S.; Daems, N.; Bals, S.; Breugelmans, T. |
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Title |
Synthesis and characterization of a highly electroactive composite based on Au nanoparticles supported on nanoporous activated carbon for electrocatalysis |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
ChemElectroChem |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
1-11 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT) |
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Abstract |
A facile, “one-pot”, chemical approach to synthesize gold-based nanoparticles finely dispersed on porous activated carbon (Norit) was demonstrated in this work. The pH of the synthesis bath played a critical role in determining the optimal gold-carbon interaction, which enabled a successful deposition of the gold nanoparticles onto the carbon matrix with a maximized metal utilization of 93 %. The obtained AuNP/C nanocomposite was characterized using SEM, HAADF-STEM electron tomography and electrochemical techniques. It was found that the Au nanoparticles, with diameters between 5 and 20 nm, were evenly distributed over the carbon matrix, both inside and outside the pores. Electrochemical characterization indicated that the composite had a very large electroactive surface area (EASA), as high as 282.4 m2 gAu-1. By exploiting its very high EASA, the catalyst was intended to boost the productivity of glucaric acid in the electrooxidation of its precursor, gluconic acid. However, cyclic voltammetry experiments revealed a very limited reactivity towards gluconic acid oxidation, due to the spacial hindrance of gluconic acid molecule which prevented diffusion inside the catalyst nanopores. On the other hand, the as-synthesized nanocomposite promises to be effective towards the ORR, and might thus find potential application as anode catalyst for fuel cells as well as for the scalability of all those electrochemical reactions involving small molecules with high diffusivity and catalysed by noble metals (i. e. CO2, CH4, N2, etc..). Electrocatalysis: Gold nanoparticles with diameter between 5 and 20 nm evenly distributed onto porous activated carbon (Norit) were obtained using a facile “one-pot” chemical synthesis technique with very high metal utilization. The AuNP/C nanocomposite was characterized using SEM, HAADF-STEM electron tomography and electrochemical techniques, revealing a very large electroactive surface area (EASA). The figure shows the HAADF-STEM image (a) and the respective EDX elemental distribution (b) for the AuNP/C composite with 9.3 % Au-loading developed in this work (Au is marked in red and C in green).image |
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Wos |
001060398900001 |
Publication Date |
2023-09-08 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2196-0216 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4 |
Times cited |
1 |
Open Access |
OpenAccess |
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Notes |
The research described in this article has not been supported by the Climate, Infrastructure and Environment Executive Agency of the European Commission. The views expressed in this article have not been adopted or in any way approved by the European Commission and do not constitute a statement of the European Commission & apos;s views.r S. Hoekx was supported by Research Foundation Flanders (FWO 1S42623N). The authors would like to thank Prof. Dr. Christophe Vande Velde, University of Antwerp, for the XRD analysis. |
Approved |
Most recent IF: 4; 2023 IF: 4.136 |
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Call Number |
UA @ admin @ c:irua:199210 |
Serial |
8941 |
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Author |
Arenas Esteban, D.; Pacquets, L.; Choukroun, D.; Hoekx, S.; Kadu, A.A.; Schalck, J.; Daems, N.; Breugelmans, T.; Bals, S. |
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Title |
3D characterization of the structural transformation undergone by Cu@Ag core-shell nanoparticles following CO₂ reduction reaction |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Chemistry of materials |
Abbreviated Journal |
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Volume |
35 |
Issue |
17 |
Pages |
6682-6691 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT) |
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Abstract |
The increasing use of metallic nanoparticles (NPs) is significantly advancing the field of electrocatalysis. In particular, Cu/Ag bimetallic interfaces are widely used to enhance the electrochemical CO2 reduction reaction (eCO(2)RR) toward CO and, more recently, C-2 products. However, drastic changes in the product distribution and performance when Cu@Ag core-shell configurations are used can often be observed under electrochemical reaction conditions, especially during the first few minutes of the reaction. Possible structural changes that generate these observations remain underexplored; therefore, the structure-property relationship is hardly understood. In this study, we use electron tomography to investigate the structural transformation mechanism of Cu@Ag core-shells NPs during the critical first minutes of the eCO(2)RR. In this manner, we found that the crystallinity of the Cu seed determines whether the formation of a complete and homogeneous Ag shell is possible. Moreover, by tracking the particles' transformations, we conclude that modifications of the Cu-Ag interface and Cu2O enrichment at the surface of the NPs are key factors contributing to the product generation changes. These insights provide a better understanding of how bimetallic core-shell NPs transform under electrochemical conditions. |
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Wos |
001061530700001 |
Publication Date |
2023-08-31 |
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ISSN |
0897-4756; 1520-5002 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
8.6 |
Times cited |
1 |
Open Access |
Not_Open_Access: Available from 29.02.2024 |
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Notes |
L.P. was supported through a PhD fellowship for strategicbasic research (1S56920N) of the Research Foundation – Flanders(FWO). S.H. was supported through a PhD fellowship for strategic basicresearch (1S42623N) of the Research Foundation – Flanders (FWO).S.B., D.A.E., and A.A.K. acknowledge financial support from ERC Consolidator Grant Number 815128 REALNANO. This research was financed by the researchcouncil of the University of Antwerp (BOF-GOA 33928). |
Approved |
Most recent IF: 8.6; 2023 IF: 9.466 |
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Call Number |
UA @ admin @ c:irua:199187 |
Serial |
8825 |
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Author |
Daele, K.V.; Arenas‐Esteban, D.; Choukroun, D.; Hoekx, S.; Rossen, A.; Daems, N.; Pant, D.; Bals, S.; Breugelmans, T. |
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Title |
Enhanced Pomegranate‐Structured SnO2Electrocatalysts for the Electrochemical CO2Reduction to Formate |
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A1 Journal article |
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Year |
2023 |
Publication |
ChemElectroChem |
Abbreviated Journal |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT) |
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Abstract |
Although most state-of-the-art Sn-based electrocatalysts yield promising results in terms of selectivity and catalyst activity, their stability remains insufficient to date. Here, we demonstrate the successful application of the recently developed pomegranate-structured SnO2 (Pom. SnO2) and SnO2@C (Pom. SnO2@C) nanocomposite electrocatalysts for the efficient electrochemical conversion of CO2 to formate. With an initial selectivity of 83 and 86% towards formate and an operating potential of -0.72 V and -0.64 V vs. RHE, respectively, these pomegranate SnO2 electrocatalysts are able to compete with most of the current state-of-the-art Sn-based electrocatalysts in terms of activity and selectivity. Given the importance of electrocatalyst stability, long-term experiments (24 h) were performed and a temporary loss in selectivity for the Pom. SnO2@C electrocatalyst was largely restored to its initial selectivity upon drying and exposure to air. Of all the used (24 h) electrocatalysts, the pomegranate SnO2@C had the highest selectivity over a time period of one hour, reaching an average recovered FE of 85%, while the commercial SnO2 and bare pomegranate SnO2 electrocatalysts reached an average of 79 and 80% FE towards formate, respectively. Furthermore, the pomegranate structure of Pom. SnO2@C was largely preserved due to the presence of the heterogeneous carbon shell, which acts as a protective layer, physically inhibiting particle segregation/pulverisation and agglomeration. |
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Wos |
000936694800001 |
Publication Date |
2023-02-15 |
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Edition |
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ISSN |
2196-0216 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
4 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
European Regional Development Fund, E2C 2S03-019 ; |
Approved |
Most recent IF: 4; 2023 IF: 4.136 |
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Call Number |
EMAT @ emat @c:irua:195228 |
Serial |
7249 |
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Author |
Choukroun, D.; Pacquets, L.; Li, C.; Hoekx, S.; Arnouts, S.; Baert, K.; Hauffman, T.; Bals, S.; Breugelmans, T. |
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Title |
Mapping composition–selectivity relationships of supported sub-10 nm Cu–Ag nanocrystals for high-rate CO₂ electroreduction |
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A1 Journal article |
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Year |
2021 |
Publication |
Acs Nano |
Abbreviated Journal |
Acs Nano |
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Volume |
15 |
Issue |
9 |
Pages |
14858-14872 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT) |
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Abstract |
Colloidal Cu–Ag nanocrystals measuring less than 10 nm across are promising candidates for integration in hybrid CO2 reduction reaction (CO2RR) interfaces, especially in the context of tandem catalysis and selective multicarbon (C2–C3) product formation. In this work, we vary the synthetic-ligand/copper molar ratio from 0.1 to 1.0 and the silver/copper atomic ratio from 0 to 0.7 and study the variations in the nanocrystals’ size distribution, morphology and reactivity at rates of ≥100 mA cm–2 in a gas-fed recycle electrolyzer operating under neutral to mildly basic conditions (0.1–1.0 M KHCO3). High-resolution electron microscopy and spectroscopy are used in order to characterize the morphology of sub-10 nm Cu–Ag nanodimers and core–shells and to elucidate trends in Ag coverage and surface composition. It is shown that Cu–Ag nanocrystals can be densely dispersed onto a carbon black support without the need for immediate ligand removal or binder addition, which considerably facilitates their application. Although CO2RR product distribution remains an intricate function of time, (kinetic) overpotential and processing conditions, we nevertheless conclude that the ratio of oxygenates to hydrocarbons (which depends primarily on the initial dispersion of the nanocrystals and their composition) rises 3-fold at moderate Ag atom % relative to Cu NCs-based electrodes. Finally, the merits of this particular Cu–Ag/C system and the recycling reactor employed are utilized to obtain maximum C2–C3 partial current densities of 92–140 mA cm–2 at −1.15 VRHE and liquid product concentrations in excess of 0.05 wt % in 1 M KHCO3 after short electrolysis periods. |
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000703553600082 |
Publication Date |
2021-08-24 |
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ISSN |
1936-0851 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
13.942 |
Times cited |
25 |
Open Access |
OpenAccess |
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Notes |
D.C. acknowledges Thomas Kenis for configuring the analytical instrumentation (HPLC/GC-FID/ICP-MS), Hannelore Andries for assistance with ICP-MS measurements, and Dr. Saeid Pourbabak and Dr. Tine Derez for assistance with Cu sputtering. L.P. was supported by Research Foundation of Flanders (FWO 1S56920N). S.B. acknowledges financial support from ERC Consolidator grant number 815128 REALNANO. S.B. and T.B. acknowledge financial support from the university research fund (BOF-GOA-PS ID no. 33928).; sygmaSB |
Approved |
Most recent IF: 13.942 |
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Call Number |
UA @ admin @ c:irua:180305 |
Serial |
6844 |
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