Cobalt-Doped Carbon Gels as Electro-Catalysts for the Reduction of CO2 to Hydrocarbons

Abdalla Abdelwahab,Agustín Pérez-Cadenas,Jesica Castelo-Quibén,Francisco Maldonado-Hódar,Francisco Carrasco-Marín,Abdelhakim Elmouwahidi,María Pérez-Cadenas

doi:10.3390/catal7010025

Abdalla Abdelwahab, Agustín Pérez-Cadenas + Show 5 more

Open Access

https://doi.org/10.3390/catal7010025

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Abstract

Two original series of carbon gels doped with different cobalt loadings and well-developed mesoporosity, aerogels and xerogels, have been prepared, exhaustively characterized, and tested as cathodes for the electro-catalytic reduction of CO2 to hydrocarbons at atmospheric pressure. Commercial cobalt and graphite sheets have also been tested as cathodes for comparison. All of the doped carbon gels catalyzed the formation of hydrocarbons, at least from type C1 to C4. The catalytic activity depends mainly on the metal loading, nevertheless, the adsorption of a part of the products in the porous structure of the carbon gel cannot be ruled out. Apparent faradaic efficiencies calculated with these developed materials were better that those obtained with a commercial cobalt sheet as a cathode, especially considering the much lower amount of cobalt contained in the Co-doped carbon gels. The cobalt-carbon phases formed in these types of doped carbon gels improve the selectivity to C3-C4 hydrocarbons formation, obtaining even more C3 hydrocarbons than CH4 in some cases.

Highlights

The continuous increase of the CO2 atmospheric concentration is thought to be one of the main causes of global climate change [1]
The carbon gel morphology, which was studied by scanning electron microscopy (SEM) (Figure 1), is typicalThe forcarbon
R-F carbon gels showing a was carbon network formed by nearly spherical particles gel morphology, which studied by scanning electron microscopy (SEM)

Summary

Introduction

The continuous increase of the CO2 atmospheric concentration is thought to be one of the main causes of global climate change [1]. Different strategies of CO2 reduction to valuable compounds are being studied, like catalytic reduction [2], photo-catalytic reduction [3,4,5], and electro-catalytic reduction [6] Renewable energy sources such as solar, wind and tidal electricity are receiving a lot of attention, but they do not produce the constant and tunable currents that fossil fuels provide. Storage of surplus electrical energy produced during peak production periods and its release during peak demand periods is, crucial, especially as peak production and peak demand periods often do not coincide In this line, the electro-catalytic reduction of CO2 to hydrocarbons can be an alternative strategy to address the problem of storing temporary and local surpluses of renewable energy [6,7]. In a one-pot process, water is split to provide the required hydrogen atoms/ions which are reacted with CO2 to Catalysts 2017, 7, 25; doi:10.3390/catal7010025 www.mdpi.com/journal/catalysts

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