Researchers got a step closer to achieving artificial photosynthesis, which could be helpful in the highly dreamed of process of harnessing climate changed -related atmospheric carbon dioxide and converting it into green fuel.
A research team demonstrated that bimetallic nanoparticles of gold and copper could be used as a catalyst, the DOE/Lawrence Berkeley National Laboratory report. The experiment demonstrated the electronic and geometric effects on the reduction reaction.
"Acting synergistically, the electronic and geometric effects dictate the binding strength for reaction intermediates and consequently the catalytic selectivity and efficiency in the electrochemical reduction of carbon dioxide. In the future, the design of carbon dioxide reduction catalysts with good activity and selectivity will require the careful balancing of these two effects as revealed in our study," said study leader Peidong Yang, a chemist with Berkeley Lab's Materials Sciences Division.
By alloying the researchers believe they can harness the binding strength of intermediates on the catalyst surface, this process could lead to carbon dioxide reduction through reaction kinetics. Nanoparticles could make ideal catalysts because they have high surface-to-volume and surface-to-mass ratios. In this study the researchers used uniform gold-copper bimetallic nanoparticles with different compositions ordered into monolayers to reduce carbon dioxide.
"Based on our observations, the activity of the gold-copper bimetallic nanoparticles can be explained in terms of the electronic effect, in which the binding of intermediates can be tuned using different surface compositions, and the geometric effect, in which the local atomic arrangement at the active site allows the catalyst to deviate from the scaling relation," Yang said.
The effects observed in the gold-copper bimetallic nanoparticles could be seen in a variety of other materials.
"We expect the effects we observed to be universal for a wide range of catalysts, as evidenced in other areas of catalysis such as the hydrogen evolution and oxygen reduction reactions," said Dohyung Kim, a member of Yang's research group and a collaborator in this study. "The factors we have identified are based on the solid concept of electrocatalysis."
Knowing the influence of the electronic and geometric effects could help researcher predict how intermediate products in carbon reduction (such as carboxylic acid and carbon monoxide) will react with the surface of the catalyst.
"My group is now using the insights gained from this study in the design of next generation carbon dioxide reduction catalysts," Yang said.
The findings were published in recent edition of the journal Nature Communications.
