Direct, in situ determination of pH and solute concentrations in formic acid dehydrogenation and CO(2) hydrogenation in pressurised aqueous solutions using (1)H and (13)C NMR spectroscopy.

In water, spin-lattice relaxation times (T(1)) and calibration curves for chemical shifts have been determined for the (13)C and the (1)H(C) atoms in HCOOH, HCOONa, CO(2), Na(2)CO(3) and NaHCO(3) by NMR spectroscopy. These data facilitate kinetic and mechanistic studies for H(2) storage/delivery in the carbon dioxide-formic acid systems under H(2) and CO(2) pressures.