DFT calculation, a practical tool to predict the electrochemical behaviour of organic electrolytes in aqueous redox flow batteries

Herein, a computational predictive tool for redox flow batteries based on NBO and ADCH charge distribution studies is presented and supported by experimental evidence. Using highly water soluble (>2 M) non-planar 2,2′ - bipyridinium salts as a case of study, this work presents a DFT protocol that successfully predicts the stability and forecasts their potential application as active materials for Aqueous Organic Redox Flow Batteries (AORFB). An initial theoretical-experimental characterization of selected bipyridines served to determine the effect of the ring size, geometry, and electron density on the physico-chemical properties of the materials. Nonetheless, the NBO and ADCH charge analyses were essential tools to understand the stability of the reduced species in terms of electronic delocalization and the importance of the molecular design on the stability of electrolyte for AORFB. Based on these results, the cell performance of seven-membered 2,2′ -bypiridinium salt, (2), and m-Me substituted homologous, (4), were compared. The significantly lower capacity decay rendered by compound 4 based electrolyte, (0.35%/cycle) compared with compound 2 based electrolyte, (0.71%/cycle) was in good agreement with the predicted stability. The aim of this work is to highlight the powerful synergy between DFT calculations and organic chemistry in predicting the behaviour of different negolytesThis work has been funded by the European Union under the HIGREEW project, Affordable High-performance Green Redox Flow batteries (Grant agreement no. 875613). H2020: LC-BAT-4-2019. A.C. Lopes acknowledges the Ramon y Cajal (RYC2021-032277-I) research fellowship, the financial support from Ministerio de Ciencia e Innovacion ´ / AEI /10.13039/501100011033 and from European Union NextGenerationEU/PRTR. We also thank the CCC-UAM (Graforr project) for allocation of computer tim

Improving process efficiency of gold-catalyzed hydration of alkynes : merging catalysis with membrane separation

In this report, we investigate the integration of a membrane separation protocol in line with the gold-catalyzed hydration of alkynes. The catalytic reaction is optimised towards that end and subsequently merged with membrane technology via the development of an organic solvent nanofiltration (OSN) procedure. The protocol is investigated over both ceramic and polymeric membranes. Several gold catalysts were screened in the hydration of diphenylacetylene 1, and high rejection was observed in all cases using Borsig-type polymeric membranes. Catalyst recycling was also achieved up to 4 times using [Au(OTf)(IPr)] (3). In addition, the retained catalyst in the last catalytic cycle was analyzed and readily converted into [Au(Cl)(IPr)] (synthetic precursor to 3), using a straightforward treatment. The sustainability of the process was improved by using a green solvent, 2-methyltetrahydrofuran (Me-THF), and by reducing the amount of solvent used via the implementation of a second membrane