Researchers at the Fritz Haber Institute in Berlin have achieved a breakthrough in understanding proton transport, a fundamental process in biological systems and energy technologies like fuel cells. By cooling phosphoric acid dimers to just 0.37 Kelvin, the team precisely determined their structure, revealing a single, stable configuration at the heart of what’s been termed “Nature’s proton highway.”
The study, published in the Journal of Physical Chemistry A, focused on the deprotonated dimer of phosphoric acid (H3PO4·H2PO4-). Scientists have long known phosphoric acid is exceptionally efficient at moving charges, but the precise mechanism behind this conductivity remained elusive. The research team employed infrared spectroscopy and quantum chemical calculations to analyze the molecular structure.
Contrary to predictions from calculations, the experiment revealed only one structural species of the phosphoric acid dimer formed at near absolute zero. This finding challenges existing theoretical models and suggests a surprisingly simple underlying structure governs proton transfer. The observed structure shares a common hydrogen bonding motif with other phosphoric acid-containing clusters, indicating this motif may be a general characteristic of phosphoric acid interactions.
“The study sheds light on the molecular basis of Nature’s proton highway: phosphoric acid’s renowned proton conductivity,” according to the Fritz Haber Institute. Understanding this process could pave the way for designing new materials with enhanced proton conductivity, improving the efficiency of fuel cells and other energy technologies. The research also deepens the understanding of proton transfer within biological systems, a crucial process for life.
The findings build on previous work identifying phosphoric acid’s role in numerous chemical processes, both within living organisms and in industrial applications. The team’s success in isolating and characterizing a single stable structure at extremely low temperatures provides a crucial foundation for future investigations into the dynamics of proton transport at more realistic temperatures.
