Researchers at ETH Zurich have achieved a major breakthrough in the development of catalysts for “green” chemistry. They engineered a structure featuring isolated metal atoms, as detailed in a publication in the journal Nature Nanotechnology.
Methanol remains a vital feedstock for fuels and plastics, playing a significant part in the long-term shift away from fossil resources. Utilizing “green” energy for its production offers a pathway to climate-neutral processing, enabling the conversion of atmospheric $\text{CO}_2$ into valuable commodities.
Previously, the scientific community had reported on a scalable technology capable of successfully transforming $\text{CO}_2$ and hydrogen into methanol. This methodology relies on employing a chemical catalyst based on indium oxide combined with a small amount of palladium, which yields pure methanol alongside the byproduct, water.
The novel achievement by these scientists is the creation of a single-atom structured catalyst. Unlike conventional counterparts, where metals aggregate into particles comprising hundreds of atoms, this new design anchors individual active atoms—in this case, indium—separately onto a hafnium oxide surface. Experiments verified that synthesizing methanol from $\text{CO}_2$ is more efficient when using isolated indium atoms on hafnium oxide compared to indium presented as multi-atom nanoparticles.
The research team devised several synthesis techniques specifically for the targeted anchoring of individual indium atoms onto the hafnium oxide surface. A key advantage of the innovation lies in the unique characteristics of the support material’s structure, which furnishes the atoms with a stable environment.
In one test, the precursor materials were subjected to combustion in a flame at extreme temperatures ranging between 2000 and $3000^\circ\text{C}$ before being rapidly quenched. The indium remained stably fixed on the surface throughout.
Through these experiments, the chemists demonstrated that this novel technology facilitates reactions typically demanding elevated heat and significant pressure. Specifically, the synthesis of methanol from $\text{CO}_2$ and hydrogen requires temperatures up to $300^\circ\text{C}$ and pressures five dozen times that of the atmosphere.
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