Dr. Qingyang Hu's recent JACS paper featured on JACS spotlights.
Dr. Qingyang Hu's recently published JACS paper was selected to be featured in JACS Spotlights "Tracking Hydrogen Deep in the Earth’s Mantle".
The movement of water from the Earth’s crust to its deeper layers affects both the chemical properties of mantle minerals as well as the geochemical evolution of the planet. Under high-pressure conditions, the asymmetric hydroxyl bonds present in some minerals form a symmetric configuration in which O is present at the center of the two H atoms. This placement improves their thermal stability and makes it possible for water-bearing minerals to be present deeper in the earth. However, how H is recycled from the mantle is unclear.
To investigate this phenomenon, Qingyang Hu and co-workers use a combination of modeling and experiments to better understand the dehydrogenation mechanism of one such water-bearing mineral, FeO2H (DOI: 10.1021/jacs.7b06528). Their work reveals that at high temperature and under high pressure, about half the O-H bonds rupture, releasing ~ 50% of this mineral’s hydrogen content as it transitions to a pyrite-type phase. The authors speculate that the hydrated minerals might concentrate in the oceanic crust, from which they descend to the mantle, and then stabilize there by releasing hydrogen. The findings have significant implications for chemistry occurring in the Earth’s deeper layers.