The GAO Materials Chemistry Research Group

It is not well known, but the most potent greenhouse gas is, surprisingly, neither carbon dioxide nor methane, but a colorless, odorless, and inert gas known as sulfur hexafluoride (SF6). With a global warming potential 23,900 times that of CO2 and being synthetic in nature (it is not absorbed on destroyed naturally), rising SF>6 concentrations are of major concern. Currently, electrical utilities and equipment are responsible for consuming 80% of the 10 000 tons of SF6 produced every year, an amount which is growing with the increasing global production and demand for renewable forms of energy, such as wind and solar. Can chemists and engineers rise to the challenge of solving the looming SF6 problem?

See full article at Advanced Science News.

Atomically precise heterostrucutures present chemically interesting active sites for catalysis but are often expensive and/or challenging to synthesize. In this article, we report a synthetic strategy to conformally coating Cu atoms onto the surface of Pd/HyWO3-x by anchoring Cu(I)OtBu to the Brønsted acidic protons of the bronze. It was observed that just 0.2 at.% of Cu was able to increase the catalytic performance of CO2 hydrogenation to CO by 500%. This metal anchoring method enables atom precise modification of the surfaces of metal oxide nanomaterials for catalytic applications, circumventing the need for complex and expensive atomic layer deposition processes.

See full article at Journal of the American Chemical Society.

A long-standing challenge in the field of CO2 utilization is how to stabilize Cu2O, an earth-abundant, non-toxic, low-cost (photo)catalyst that can facilitate reduction of CO2 to CO against the irreversible redox disproportionation Cu2O → Cu + CuO, responsible for its instability.

Lili Wan and Wei Sun and coworkers in the Ozin group have solved this problem as reported in their Nature Catalysis paper, by modifying the surface of Cu2O nanocubes with a mixed valence surface frustrated Lewis pair (SFLP), Cu(I,II) ●● OH, which serves to eliminate the redox disproportionation. As depicted in the illustration, H2 undergoes heterolytic dissociation on the SFLP, water is eliminated to create an [O] vacancy and Cu(I) is reduced to Cu(0). Adsorption of CO2 at the [O] vacancy site drives the conversion to CO thereby completing the photocatalytic RWGS reaction cycle

See full article at Nature Catalysis.

Everybody knows the leaf makes carbohydrates and the trunk makes paper. But did you know that waste from the paper making process can make fuel from carbon dioxide, water and sunlight? Black liquor, an industrial waste product of papermaking, is primarily used as a low‐grade combustible energy source. Despite its high lignin content, the potential utility of black liquor as a feedstock in products manufacturing, remains to be exploited. In this paper, black liquor is demonstrated to function as a primary feed‐stock for synthesizing graphene quantum dots that exhibit both up‐conversion and photoluminescence when excited using visible/near‐infrared radiation, enabling solar‐powered generation of H2 from H2O, and CO from H2O–CO2, using broadband solar radiation.

See full article at Angewandte Chemie.

In their paper, “Living Atomically Dispersed Cu Ultrathin TiO2 Nanosheet CO2 Reduction Photocatalyst”, Jiang, Sun, and co-authors report a serendipitous living photodeposition method can make atomically dispersed Cu immobilized on ultrathin TiO2 nanosheets, which can photocatalytically reduce an aqueous solution of CO2 to CO and in the process can be recycled in a straightforward procedure on becoming oxidatively deactivated.

See full article at Advanced Science.

The extraction and combustion of fossil natural gas, consisting primarily of methane, generates vast amounts of greenhouse gases that contribute to climate change. However, as a result of recent research efforts, “solar methane” can now be produced through the photo-catalytic conversion of carbon dioxide and water to methane and oxygen. This approach could play an integral role in realizing a sustainable energy economy by closing the carbon cycle and enabling the efficient storage and transportation of intermittent solar energy within the chemical bonds of methane molecules. In this article, Uli and co-authors explore the latest research and development activities involving the light-assisted conversion of carbon dioxide to methane.
See full article at Nature Communications.

How can we replace the fossil-fuel-derived heat that conventionally drives chemical processes with an emissions-free alternative? The current standard in industrial-scale heterogeneous catalytic processes, such as the production of ammonia and hydrogen, is to use heat supplied by the combustion of natural gas. Heat can alternatively be supplied from non-fossil sources, such as renewable electricity; however, assessing the net impact on carbon emissions of electricity-based processes remains non-trivial.
See full article at Advanced Science News.

At standard temperature and pressure, CO2 exists as a gas. On cooling to -78.5 °C, it becomes a solid called dry ice, which is a common refrigerant. At a critical temperature of 31.1 °C and pressure 72.9 atmospheres, however, CO2 becomes a supercritical fluid with properties intermediate to a gas and liquid. In this form, CO2 fills a containment vessel and exhibits a low viscosity reminiscent of a gas but retains the high density of a liquid. It turns out that supercritical CO2 also has rather appealing properties as both solvent and reagent in the electrochemical reduction of CO2 to a variety of products.
See full article at Advanced Science News.

wo-dimensional materials hold great potential as catalysts for the heterogeneous conversion of CO2 to synthetic fuels and chemicals. In this paper, Yan et al. demonstrate the performance of nickel@siloxene to be highly sensitive to the nickel component being located either on the interior or exterior of adjacent siloxene nanosheets. Control over the location of nickel is achieved by employing the terminal groups of siloxene and varying the solvent used during its nucleation and growth, which ultimately determines the distinct reaction intermediates and pathways for the catalytic CO2 methanation. A CO2 methanation rate of 100 mmol gNi−1 h−1 is achieved with over 90% selectivity when nickel resides specifically between the sheets of siloxene.
See full article at Nature Communications.

Titanium dioxide is the only known material that can enable gas-phase CO2 photocatalysis in its anatase and rutile polymorphic forms. In their paper, however, Dr. Yan and co-authors demonstrate that the lesser known rhombohedral polymorph of indium sesquioxide, like its well-documented cubic polymorph, can act as a CO2 hydrogenation photocatalyst with the ability to produce CH3OH and CO.
See full article at Nature Communications.