Direct Electrochemical Reduction of Bicarbonate to Formate Using Tin Catalyst

Andreu Bonet Navarro,Adrianna Nogalska,Ricard Garcia-Valls

doi:10.3390/electrochem2010006

Andreu Bonet Navarro, Adrianna Nogalska + Show 1 more

Open Access

https://doi.org/10.3390/electrochem2010006

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Journal: Electrochem	Publication Date: Feb 10, 2021
Citations: 13	License type: CC BY 4.0

Affiliation: Rovira i Virgili University

Abstract

Nowadays, the self-accelerating increase in global temperatures strengthens the idea that the cutting of CO2 emissions will not be enough to avoid climate change, thus CO2 from the atmosphere must be removed. This gas can be easily trapped by converting it to bicarbonate using hydroxide solutions. However, bicarbonate must be converted into a more valuable product to make this technology profitable. Several studies show great efficiency when reducing bicarbonate solutions saturated with pure CO2 gas to formate. However, those approaches don’t have a real application and our objective was to obtain similar results without pure CO2 saturation. The method consists of electroreduction of the bicarbonate solution using bulk tin (Sn) as catalysts. Tin is a relatively cheap material that, according to previous studies performed in saturated bicarbonate solutions, shows a great selectivity towards formate. The 1H NMR analysis of bicarbonate solutions after electroreduction show that, without pure CO2 gas, the faradic efficiency is around 18% but almost 50% for saturated ones. The formate obtained could be used to power formate/formic acid fuel cells obtaining a battery-like system, with greater energy density than common lithium batteries, but electroreduction efficiency needs to be improved to make them competitive.

Highlights

Since the start of the industrial revolution, the atmospheric CO2 levels increased drastically and exceeded the 400 ppm in 2016 [1]
The formate obtained could be used to power formate/formic acid fuel cells obtaining a battery-like system, with greater energy density than common lithium batteries, but electroreduction efficiency needs to be improved to make them competitive
Our goal is to study the viability of reducing a non-CO2 saturated bicarbonate solution into formate using a bulk tin catalyst, which is a relatively cheap material, simple to use and with great selectivity towards formate in mild conditions [22,23,24,25,26]

Summary

Introduction

Since the start of the industrial revolution, the atmospheric CO2 levels increased drastically and exceeded the 400 ppm in 2016 [1]. For this reason, some studies indicate that just cutting off or reducing the CO2 emissions will not be enough to avoid or mitigate the effects of climate change, and CO2 removal from the atmosphere is going to be necessary [2]. One way to absorb atmospheric CO2 is by transforming it into bicarbonate using hydroxide solutions, like the system developed by A. Bicarbonate is a product with low value and not many applications, but its conversion to more useful and valuable hydrocarbons is becoming an economically viable way to reuse it [4]

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