Nickel Impregnated Cerium-Doped Strontium Titanate Fuel Electrode: Direct Carbon Dioxide Electrolysis and Co-Electrolysis

Abstract

Direct electrolysis of carbon dioxide and co-electrolysis of steam and carbon dioxide offers an efficient and effective method to produce CO or syngas and also utilizes CO 2 in a carbon-neutral fuel cycle. Here we report the use of composite fuel electrode containing a Sr 0.7 Ce 0.2 TiO 3±δ (SCT) and Sm 0.20 Ce 0.80 O 2-δ (SDC) backbone which has been infiltrated with nickel nitrate and decomposed to form nickel surface decoration on the ceramic scaffold. Maximum cell current during electrolysis at 850 • C was 263 mAcm −2 and 192 mAcm −2 at 1.8V for co-electrolysis and CO 2 , respectively. The infiltrated nickel particles provided a large surface area and enhanced activity during electrolysis. Fossil-based fuels remain the key component in the global energy mix. Their continued use leads to carbon dioxide emissions which contributes to climate change. To mitigate emissions, renewable energy sources (wind, solar and tidal, biomass etc.) have seen increased popularity. One of the key challenges facing the uptake of renewable electrical generation technologies is a way to store the intermittent electricity these tend to generate. Another complicating factor is the role fossil fuels play in transportation where alternatives such as hydrogen are limited by infrastructure and viable carbonfree hydrogen generation technology. Both of these issues can be addressed by producing liquid hydrocarbon fuel from renewable or excess grid electricity.1 High temperature electrolysis of steam and carbon dioxide has been shown an efficient and scalable route to producing syngas which will readily convert to a versatile range of downstream hydrocarbons.2-6 Use of a state-of-the-art solid oxide electrolysis cell with nickel-YSZ composite electrode for CO/CO 2 has also been demonstrated as a means of directly utilizing and recycling captured carbon dioxide rather than capture and storage. However, using traditional nickel-based composite electrodes showed relatively high levels of passivation due to sulfur impurities in the gas feed streams. 7The need for a robust alternative to nickel-composite electrode materials has been widely documented for solid oxide fuel cells. ). Typically these materials are prepared with a small degree of cation non-stoichiometry to maintain a single phase during synthesis. In the case of La-doped STO it has been found experimentally that oxygen excess can be accommodated by the formation of layered intergrowths rich in La. 22 Nb, Y and Ce doped materials do not seem to support intergrowth structures and tend to precipitate second phases if the stoichiometry, defect regime and processing conditions are not coordinated.Electrochemical cell performance has been reported for Y, La and Nb-doped titanate materials 23,24 with encouraging testing results, however, many of the titanate materials show negligible catalytic activity. 25Significant performance improvements have been shown in electrodes based on a titanate backbone where the microstructure has been decorated with metal nanoparticles. 25,26 Typically the...

Oxygen Exchange Kinetics of SrTiO3 Single Crystals: A Non‐Destructive, Quantitative Method

“…OSEC experiments on pure SrTiO 3 single crystals lead to exchange parameters comparable to those found in literature (see Table ). It is well known that catalytic activity on metal oxide surfaces can be rapidly increased through deposition of porous metal layers and by metal ion implantation . In this work, for the first time on single crystals both of these methods have been examined using OSEC and leading to different oxygen exchange behaviors.…”

“…[]. Other groups have already shown, that ion implantation can be a promising way to increase chemical reaction rates at metal oxide surfaces, especially because the mass of the active material is low and the resulting layer resists to corrosion attacks . However, those reactions did not involve an incorporation of reactants unlike the process presented in this paper.…”

Exsolution of nanoparticles on A-site-deficient lanthanum ferrite perovskites: its effect on co-electrolysis of CO2 and H2O

“…A great deal of effort has been made in the past years in electrocatalytic conversion of CO 2 into other chemicals. [2][3][4][5][6] It should be noted that if renewable energy sources are available for electrolysis, directly splitting CO 2 into CO and O 2 using electrochemical cells is a relatively simple and effective way to promote the reduction of global CO 2 concentration in the atmosphere. 4,[7][8][9] Moreover, electrochemical cells contribute to the environmentally friendly aspect of hydrogen production as opposed to current H 2 production methods which heavily rely on fossil fuels, generating CO 2 .…”

“…[2][3][4][5][6] It should be noted that if renewable energy sources are available for electrolysis, directly splitting CO 2 into CO and O 2 using electrochemical cells is a relatively simple and effective way to promote the reduction of global CO 2 concentration in the atmosphere. 4,[7][8][9] Moreover, electrochemical cells contribute to the environmentally friendly aspect of hydrogen production as opposed to current H 2 production methods which heavily rely on fossil fuels, generating CO 2 . 10 In this vision, utilization of electricity-to-chemicals through electrolysis cells is a practical method of utilizing renewable energy resources that are inherently intermittent.…”

“…It is being increasingly recognized that perovskite oxides with the generic formula ABO 3 are effective cathode materials for high-temperature electrolysis. 4,[13][14][15][16][17] In this chemical formula, A represents an alkali or alkaline earth metal ion coordinated to twelve oxygen atoms, B represents a transition metal ion octahedrally coordinated to six oxygen atoms, and O represents oxygen. A and/or B sites in the formula can be doped systematically to enhance the transport properties and the electrochemical activity of the material.…”