Multivalent Sn species synergistically favours the CO 2 -into-HCOOH conversion
TL;DR: In this article, the role of various valence Sn species on the CO2-to-HCOOH conversion was investigated. And the authors showed that multivalent Sn species synergistically energize CO2 activation, the HCOO* adsorption, and the electron transfer, which make Sn/SnO/snO2 nanosheets favor the conversion from CO2 into HCOOH in both thermodynamics and kinetics.
Abstract: Although Sn-based catalysts have recently achieved considerable improvement in selective electro-catalyzing CO2 into HCOOH, the role of various valence Sn species is not fully understood due to the complexity and uncertainty of their evolution during the reaction process. Here, inspired by the theoretical simulations that the concomitant multivalent Sn (Sn0, Sn11 and SnIV) can significantly motivate the intrinsic activity of Sn-based catalyst, the Sn/SnO/SnO2 nanosheets were proposed to experimentally verify the synergistic effect of multivalent Sn species on the CO2-into-HCOOH conversion. During CO2 reduction reaction, the Sn/SnO/SnO2 nanosheets, which are prepared by the sequential hydrothermal reaction, calcined crystallization and low-temperature H2 treatment, exhibit a high FEHCOOH of 89.6% at −0.9 VRHE as well as a large cathodic current density. Systematic experimental and theoretical results corroborate that multivalent Sn species synergistically energize the CO2 activation, the HCOO* adsorption, and the electron transfer, which make Sn/SnO/SnO2 favour the conversion from CO2 into HCOOH in both thermodynamics and kinetics. This proof-of-concept study establishes a relationship between the enhanced performance and the multivalent Sn species, and also provides a practicable and scalable avenue for rational engineering high-powered electrocatalysts.
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01 Mar 2021
109 citations
TL;DR: In this article, the authors used the BL14W1 station for XAFS measurement in Shanghai Synchrotron Radiation Facility (SSRF) in the Middle East and China.
Abstract: This work was supported by King Abdullah University of Science and Technology. The authors thank the BL14W1 station for XAFS measurement in the Shanghai Synchrotron Radiation Facility (SSRF)
61 citations
TL;DR: In this article, ultra-thin flower-like Bi2O2CO3 nanosheets (NSs) with abundant Bi-O structures were synthesized on carbon paper via topological transformation and post-processing.
Abstract: The electrocatalytic reduction of CO2 to HCOOH (ERC-HCOOH) is one of the most feasible ways to alleviate energy crisis and solve environmental problems. Nevertheless, it remains a challenge for ERC-HCOOH to maintain excellent activity and selectivity in a wide potential window. Herein, ultra-thin flower-like Bi2O2CO3 nanosheets (NSs) with abundant Bi-O structures were in situ synthesized on carbon paper via topological transformation and post-processing. Faraday efficiency of HCOOH (FEHCOOH) reached 90% in a wide potential window (−1.5 to −1.8 V vs. Ag/AgCl). Significantly, excellent FEHCOOH (90%) and current density (47 mA·cm−2) were achieved at −1.8 V vs. Ag/AgCl. The X-ray absorption fine structure (XAFS) combined with density functional theory (DFT) calculation demonstrated that the excellent performance of Bi2O2CO3 NS was attributed to the abundant Bi-O structures, which was conducive to enhancing the adsorption of CO2* and OCHO* intermediates and can effectively inhibit hydrogen evolution. The excellent performance of Bi2O2CO3 NS over a wide potential window could provide new insights for the efficient electrocatalytic conversion of CO2.
19 citations
TL;DR: In this article, the authors compared the performance of tin oxide-derived 3D nanoparticles and 2D nanosheets deposited on gas-diffusion electrodes for CO2 conversion to formate.
Abstract: We report the effects of catalyst dimensionality on electrochemical CO2 conversion to formate by comparing the performance of tin oxide-derived 3D nanoparticles and tin oxide-derived 2D nanosheets deposited on gas-diffusion electrodes. Our results indicated that an extensive interface between the catalyst and the electrode substrate could lower the surface tin oxidation states and the hydrophobicity of the catalyst layer during CO2 electrolysis at a current density over 100 mA cm−2. This catalyst–substrate interfacial effect provides the nanosheets with a large interface area to become more selective for CO2 electrochemical reduction but with a higher overpotential requirement as compared to the 3D nanoparticle catalysts with limited interfacial area. Consequently, the electrode with nanosheets as the catalyst achieved a partial current density of formate at 116 mA cm−2 at a cathode potential of −1.03 V versus reversible hydrogen electrode, which is equivalent to a formate production rate of 36 μmol min−1 cm−2. Our work here demonstrates the importance of the catalyst–substrate interface in determining the oxidation states and wettability at the catalyst surface and the ultimate performance of the gas-diffusion electrode. These findings also have potential to guide the design of a catalyst–substrate to advance other important electrochemical processes such as fuel cells and water splitting.
18 citations
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TL;DR: In this article, the authors present a consistent picture of some key physical properties determining the reactivity of metal and alloy surfaces, and suggest that trends in reactivities can be understood in terms of the hybridization energy between the bonding and anti-bonding adsorbate states and the metal d-bands (when present).
2,008 citations
TL;DR: In this article, the product selectivity between CO and HCOO− has been investigated, which depends upon the combination of modifier atom and substrate electrode, and the order of CO selectivity agrees roughly with the electrode potential of CO2 reduction, and is rationalized in terms of stabilization of intermediate species CO−2 at the electrode surface.
1,564 citations
07 Mar 2008
TL;DR: In this article, the authors defined the energy conversion efficiency, defined as the ratio of the free energy of the products obtained in electrochemical CO2 reduction and that consumed in the reduction, would be roughly 30 to 40%.
Abstract: Carbon dioxide is a potential carbon resource abundant on earth. It is also a green house gas with a rapidly increasing atmospheric concentration during the last two centuries. Chemical fixation of CO2 is an attractive technique for utilization of carbon resources, as well as for the reduction of the atmospheric concentration of CO2. Nevertheless, CO2 is the stablest among carbon based substances under the environmental conditions. It has not been incorporated as a major industrial material. Carbon dioxide can be electrochemically reduced to useful products under mild conditions. However, the energy conversion efficiency, defined as the ratio of the free energy of the products obtained in electrochemical CO2 reduction and that consumed in the reduction, would be roughly 30 to 40%. 2 Such a low efficiency may discourage practical application of CO2 reduction in the very near future. However, the significance of the CO2 reduc-
1,381 citations
TL;DR: A nanoporous silver electrocatalyst is reported that is able to electrochemically reduce carbon dioxide to carbon monoxide with approximately 92% selectivity at a rate over 3,000 times higher than its polycrystalline counterpart under moderate overpotentials of <0.50 V.
Abstract: Electrochemical reduction of carbon dioxide to more useful products is an industrially important process. Here, the authors report a nanoporous silver catalyst that efficiently and selectively reduces carbon dioxide due to its high surface area and intrinsically high activity.
1,137 citations
TL;DR: It is found that two important factors related to intermediate binding, the electronic effect and the geometric effect, dictate the activity of gold-copper bimetallic nanoparticles, which show great mass activities, outperforming conventional carbon dioxide reduction catalysts.
Abstract: Highly efficient and selective electrochemical reduction of carbon dioxide represents one of the biggest scientific challenges in artificial photosynthesis, where carbon dioxide and water are converted into chemical fuels from solar energy. However, our fundamental understanding of the reaction is still limited and we do not have the capability to design an outstanding catalyst with great activity and selectivity a priori. Here we assemble uniform gold-copper bimetallic nanoparticles with different compositions into ordered monolayers, which serve as a well-defined platform to understand their fundamental catalytic activity in carbon dioxide reduction. We find that two important factors related to intermediate binding, the electronic effect and the geometric effect, dictate the activity of gold-copper bimetallic nanoparticles. These nanoparticle monolayers also show great mass activities, outperforming conventional carbon dioxide reduction catalysts. The insights gained through this study may serve as a foundation for designing better carbon dioxide electrochemical reduction catalysts.
1,020 citations