Solvents and Supporting Electrolytes in the Electrocatalytic Reduction of CO2

Abstract

Different electrolytes applied in the aqueous electrocatalytic CO 2 reduction reaction (CO 2 RR) considerably influence the catalyst performance. Their concentration, species, buffer capacity, and pH value influence the local reaction conditions and impact the product distribution of the electrocatalyst. Relevant properties of prospective solvents include their basicity, CO 2 solubility, conductivity, and toxicity, which affect the CO 2 RR and the applicability of the solvents. The complexity of an electrochemical system impedes the direct correlation between a single parameter and cell performance indicators such as the Faradaic efficiency; thus the effects of different electrolytes are often not fully comprehended. For an industrial application, a deeper understanding of the effects described in this review can help with the prediction of performance, as well as the development of scalable electrolyzers. In this review, the application of supporting electrolytes and different solvents in the CO 2 RR reported in the literature are summarized and discussed.

Transition metal-based catalysts for the electrochemical CO2reduction: from atoms and molecules to nanostructured materials

“…14 In addition, a proper kinetic control of the whole catalytic system is essential to achieve the desired selectivity, and factors such as the applied potential, the proton concentration in the reaction medium, and the solubility of CO 2 (e.g. about 0.03 M in common aqueous electrolytes, 0.31 M in CH 3 CN and 0.19 M in DMF 15 ) must be also carefully assessed. In the last decades, a plethora of transition metal-based catalysts have been reported for efficient CO 2 RR, ranging from molecular catalysts [16][17][18][19][20][21][22] to metal nanoparticles 23,24 and bulk heterogeneous materials.…”

Size and charge correlations in spherical electric double layers: a case study with fully asymmetric mixed electrolytes within the solvent primitive model

“…42 The interaction between large colloidal particles can be normalized in terms of solvent, once the SDLs formed from two macroparticles can be considered. The importance of charge and size correlation in such solvent-induced interactions will be quite critical to numerically simulate biological macromolecules 57 and even fuel cells 58 and batteries. 59 The current simulation method can also be applied to predict the Stern layer structure and energetics as accessed through synchrotron X-ray reectivity (XRR) experiments 60 for alkali chloride solutions on mica surfaces.…”

Electrochemical CO2 Reduction to CO Catalyzed by 2D Nanostructures

“…Among them, aqueous electrolytes are cheap, environmentally friendly, and possess high sustainability. Moreover, in aqueous electrolytes, the concentration, pH value, and buffer capacity are of equal importance for eventually affecting the efficiency and product selectivity [73]. CO 2 is highly soluble in organic electrolytes, but they are toxic, expensive and require large overpotentials compared to aqueous electrolytes.…”