The mesostructured NiO/Ni composites boost the electrochemical energy storage performance of NiO to its theoretical limit, which results from the synergism of high accessibility to electrolyte, short solid-state ion diffusion length and high conductivity owing to the unique mesostructure.
carbon sources through different technical routes, [1] which either have negative environmental impacts or deliver a poor atomic economy while being energy intensive. [2] For instance, the life-cycle greenhouse gas emission for producing a liter of bioethanol is ≈1.6 kg CO 2 equivalent. [3] For fuel ethanol with a global production of ≈104 billion liters per year, [4] the annual CO 2 emission is more than 170 million metric tons, corresponding to 0.5% of the global annual overall carbon emission. [5] New technologies are thus in demand to balance the target of environmental protection and economic development. Electrochemical CO 2 reduction (ECR) driven by renewable energies is a competitive candidate, as it converts CO 2 into liquid products like formate and alcohols with nearly net-zero CO 2 emissions. [6] Nonetheless, the Faradaic efficiency (FE) for CO 2-to-alcohol production generally remains low, typically less than 50%. [7] For instance, Gewirth and co-workers presented a nanoporous Cu-Ag alloy for the enhancement of ECR activity, with an FE toward ethanol of ≈25%. [8] Bell and co-workers reported a Cu-Ag alloy with stain effect, and the total FE of alcohol production was less than 15%. [9] Recently, Sargent and co-workers reported an enhancement of ethanol selectivity in a flow cell system by tuning binding site diversity in an Ag/ Cu catalyst, while the FE for ethanol was still less than 50%. [10] The challenge in developing effective strategies of tuning the energetics of reaction pathways limits the CO 2-to-alcohol selectivity. Based on the theoretical and experimental studies, [11] ethylene (C 2 H 4) generally dominates the C 2+ product distribution, with a theoretical prediction of an alcohol/ethylene ratio of 35:65. [12] However, Calle-Vallejo and Koper reported that ethanol presents a lower free energy position compared to ethylene in the entire reaction route of carbon monoxide (CO) electroreduction to C 2 products. [13] The poor alcohol selectivity has been attributed to the unfavorable adsorption of key intermediates in the ethanol pathway on copper, [13] such as CH 3 CHO* and CH 3 CH 2 O* proved by Chorkendorff and co-workers. [14] Thus, it is rational to hypothesize that an enhanced alcohol selectivity may arise from modulating the adsorption of key intermediates like CH 3 CH 2 O* in the ECR pathways. In addition, it is also well known that Ag component can suppress hydrogen Copper-based catalysts electrochemically convert CO 2 into multicarbon molecules. However, the selectivity toward alcohol products has remained relatively low, due to the lack of catalysts favoring the adsorption of key intermediates in the alcohol pathways. Herein, a Cu 3 Ag 1 electrocatalyst is developed using galvanic replacement of an electrodeposited Cu matrix. The Cu 3 Ag 1 electrocatalyst enables a 63% Faradaic efficiency for CO 2-to-alcohol production and an alcohol partial current density of −25 mA cm −2 at −0.95 V versus reversible hydrogen electrode, corresponding to a 126-fold enhancement in selectivity and 25-...
The continuous increase of CO2 concentration in the atmosphere has been imposing an imminent threat for global climate change and environmental hazards. In recent years, the electrochemical or photochemical conversion of CO2 into value‐added chemicals or fuels has received significant attention, as it may enable an attractive means to mitigate the atmospheric CO2 concentration and complete the imbalanced carbon‐neutral energy cycle, as well as create renewable energy resources for human use. Among the different electrocatalysts being studied, Cu‐based materials have been demonstrated as the only category of candidates that allows the conversion of CO2 into a variety of reducing products, including carbon monoxide, hydrocarbons, and alcohols. Herein, the reaction pathways for different Cu‐based catalysts for C1 and C2+ products are introduced. Then, different parameters in tuning Cu‐based electrocatalysts are summarized and discussed, including the morphologies, compositions, crystal facets, and oxide derivation. In addition, various types of parameters for CO2 electroreduction are also described, particularly the option of electrolytes such as aqueous, ionic liquids, and organic solutions. Finally, the current challenges are discussed and the potential strategies to facilitate the future development of CO2 electroreduction are summarized.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.