Recent emphasis on carbon dioxide utilization has necessitated the exploration of different catalyst compositions other than copper-based systems that can significantly improve the activity and selectivity towards specific CO2 reduction products at low applied potential. In this study, a binary CoTe has been reported as an efficient electrocatalyst for CO2reduction in aqueous medium under ambient conditions at neutral pH. CoTe showed high Faradaic efficiency and selectivity of 86.83 and 75%, respectively, for acetic acid at very low potential of − 0.25 V vs RHE. More intriguingly, C1 products like formic acid was formed preferentially at slightly higher applied potential achieving high formation rate of 547.24 μmol cm−2 h−1 at − 1.1 V vs RHE. CoTe showed better CO2RR activity when compared with Co3O4, which can be attributed to the enhanced electrochemical activity of the catalytically active transition metal center as well as improved intermediate adsorption on the catalyst surface. While reduced anion electronegativity and improved lattice covalency in tellurides enhance the electrochemical activity of Co, high d-electron density improves the intermediate CO adsorption on the catalyst site leading to CO2reduction at lower applied potential and high selectivity for C2products. CoTe also shows stable CO2RR catalytic activity for 50 h and low Tafel slope (50.3 mV dec–1) indicating faster reaction kinetics and robust functionality. Selective formation of value-added C2products with low energy expense can make these catalysts potentially viable for integration with other CO2capture technologies thereby, helping to close the carbon loop.
The Application of Transition Metal Sulfide Nanomaterials and Their Composite Nanomaterials in the Electrocatalytic Reduction of CO2: A Review
Electrocatalysis has become an important topic in various areas of research, including chemical catalysis, environmental research, and chemical engineering. There have been a multitude of different catalysts used in the electrocatalytic reduction of CO2, which include large classes of materials such as transition metal oxide nanoparticles (TMO), transition metal nanoparticles (TMNp), carbon-based nanomaterials, and transition metal sulfides (TMS), as well as porphyrins and phthalocyanine molecules. This review is focused on the CO2 reduction reaction (CO2RR) and the main products produced using TMS nanomaterials. The main reaction products of the CO2RR include carbon monoxide (CO), formate/formic acid (HCOO−/HCOOH), methanol (CH3OH), ethanol (CH3CH2OH), methane (CH4), and ethene (C2H4). The products of the CO2RR have been linked to the type of transition metal–sulfide catalyst used in the reaction. The TMS has been shown to control the intermediate products and thus the reaction pathway. Both experimental and computational methods have been utilized to determine the CO2 binding and chemically reduced intermediates, which drive the reaction pathways for the CO2RR and are discussed in this review.
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- Award ID(s):
- 2122178
- NSF-PAR ID:
- 10420501
- Date Published:
- Journal Name:
- Applied Sciences
- Volume:
- 13
- Issue:
- 5
- ISSN:
- 2076-3417
- Page Range / eLocation ID:
- 3023
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Conventional lithium-ion batteries are unable to meet the increasing demands for high-energy storage systems, because of their limited theoretical capacity. 1 In recent years, intensive attention has been paid to enhancing battery energy storage capability to satisfy the increasing energy demand in modern society and reduce the average energy capacity cost. Among the candidates for next generation high energy storage systems, the lithium sulfur battery is especially attractive because of its high theoretical specific energy (around 2600 W h kg-1) and potential cost reduction. In addition, sulfur is a cost effective and environmentally friendly material due to its abundance and low-toxicity. 2 Despite all of these advantages, the practical application of lithium sulfur batteries to date has been hindered by a series of obstacles, including low active material loading, poor cycle life, and sluggish sulfur conversion kinetics. 3 Achieving high mass loading cathode in the traditional 2D planar thick electrode has been challenged. The high distorsion of the traditional planar thick electrodes for ion/electron transfer leads to the limited utilization of active materials and high resistance, which eventually results in restricted energy density and accelerated electrode failure. 4 Furthermore, of the electrolyte to pores in the cathode and utilization ratio of active materials. Catalysts such as MnO 2 and Co dopants were employed to accelerate the sulfur conversion reaction during the charge and discharge process. 5 However, catalysts based on transition metals suffer from poor electronic conductivity. Other catalysts such as transition metal dopants are also limited due to the increased process complexities. . In addition, the severe shuttle effects in Li-S batteries may lead to fast failures of the battery. Constructing a protection layer on the separator for limiting the transmission of soluble polysulfides is considered an effective way to eliminate the shuttle phenomenon. However, the soluble sulfides still can largely dissolve around the cathode side causing the sluggish reaction condition for sulfur conversion. 5 To mitigate the issues above, herein we demonstrate a novel sulfur electrode design strategy enabled by additive manufacturing and oxidative vapor deposition (oCVD). 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Density functional theory calculation reveals the electronic state variance between the structures with and without defects, the structure with defects demonstrates the higher kinetic condition for sulfur conversion. To further identify the favorable reaction dynamic process, the in-situ XRD is used to characterize the transformation between soluble and insoluble polysulfides, which is the main barrier in the charge and discharge process of Li-S batteries. The results show the oCVD coated 3D printed sulfur cathode exhibits a much higher kinetic process for sulfur conversion, which benefits from the highly tailored hierarchal hollow structure and the defects engineering on the cathode. Further, the oCVD coated 3D printed sulfur cathode also demonstrates higher stability during long cycling enabled by the oCVD PEDOT protection layer, which is verified by an absorption energy calculation of polysulfides at PEDOT. 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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/app13053023
