New material to convert carbon dioxide into fuel

Prof. XIE Yi and Prof. SUN Yongfu’s group from Hefei National Laboratory for Physical Sciences at the Microscale (HFNL) from the University of Science and Technology of China (USTC) has achieved new progress in the field of atomically thin two-dimensional hybrid materials. The research group has constructed a new metal atomic layer with its native oxide, with efforts to disclose the crucial role of surface metal oxide in the electrocatalytic activity of its own metal, adapted from an existing cobalt-based catalyst. The full work entitled, ‘Partially oxidised atomic cobalt layers for carbon dioxide electroreduction to liquid fuel’ published on Jan 4th can be accessed here.

The electroreduction of CO₂ into useful fuels, especially if driven by renewable energy, represents a potentially ‘clean’ strategy for replacing fossil feedstocks and dealing with increasing CO₂ emissions and their adverse effects on the climate. However, the large barrier of CO₂ activation into CO₂, or other intermediates, unfortunately results in impractically high overpotentials, thus enabling it to be the most critical bottleneck in developing efficient CO₂ electroreduction.

Recently, electrocatalysts based on oxide-derived metal nanostructures were shown to enable CO₂ reduction at low potentials. However, it remains unclear how the electrocatalytic activity of these metals is influenced by their native oxides, mainly because the microstructural features, such as interfaces and defects, influence CO₂ reduction activity yet are difficult to control.

To tackle all these problems, an ideal model of the metal atomic layer with its native oxide is constructed, in order to evaluate CO₂ reduction in two well-defined catalytic sites. As a prototype, 4-atom-thick layers of co-existing Co metal and Co oxide domains are fabricated, in which the Co oxide domain is embedded in the metallic Co lattice. Based on the electrocatalytic results, the surface Co atoms confined in the synthetic 4-atom-thick layers of pure Co metal have higher intrinsic activity and selectivity toward formate production, at lower overpotentials, than surface Co atoms on bulk samples. Formate being a fuel that can be burned with no toxic byproducts, can be used as a clean energy source and can provide more energy than it took to create.

This present work demonstrates that, if placed in the correct morphology and oxidation state, a material considered nearly non-catalytic for the CO₂ electroreduction reaction can turn into an active catalyst. These findings point to novel opportunities for manipulating and improving the CO₂ electroreduction properties of metal systems, especially once the influence of both the atomic-scale structure and the presence of oxide are mechanistically more fully understood.

"This represents a fundamental scientific breakthrough," Karthish Manthiram, a Chemical Engineer from the California Institute of Technology (who was not involved in the research). "Certainly it will be a years-long process before this is worked into a successful, commercial device. But at this stage of development, by all conceivable metrics, this reaction looks very positive."

Adapted from press release by Francesca Brindle

Additional sources: Science Alert

Read the article online at: https://www.hydrocarbonengineering.com/clean-fuels/08012016/hefei-national-lab-testing-oxidised-atomic-cobalt-layers-for-carbon-dioxide-electroreduction-to-liquid-fuel-2098/