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The photocatalytic activity of (Ga1- x Zn x )(N1- x O x ), a solid solution of GaN and ZnO, for H2 and O2 evolution in the presence of methanol and silver nitrate as sacrificial reagents under visible light (λ > 420 nm) is investigated in detail. (Ga1- x Zn x )(N1- x O x ) evolves H2 from an aqueous methanol solution when loaded with nanoparticulate Rh2- y Cr y O3 as a cocatalyst, and evolves O2 from an aqueous silver nitrate solution without a cocatalyst. Structural analyses indicate that the H2 evolution activity is strongly dependent on the crystallinity and composition of the catalyst, while the rate of O2 evolution is proportionally related to the specific surface area. The activity for H2 evolution from methanol solution is of the same order as for overall water splitting, but is an order of magnitude lower than that for O2 evolution from silver nitrate solution. The results of photocatalytic reactions and photoelectrochemical measurements suggest that the rate-determining step for overall water splitting using (Ga1- x Zn x )(N1- x O x ) is the H2 evolution process.

The photoelectrochemical properties of a GaN:ZnO solid solution coated as an electrode on conductive glass are investigated through measurement of voltammograms and current–time curves. The highest photocurrent was achieved by a GaN:ZnO sample with relatively high zinc concentration (Zn/Ga = 0.42) and small particle size, presumably due to more efficient electron transfer through the porous electrode. The electrode exhibits anodic photocurrent under visible light, indicating functionality as an n-type semiconductor electrode. The estimated band-gap position of GaN:ZnO is located at satisfactory potential for water splitting. The bottom of the conduction band is similar to that for GaN, while the top of the valence band is substantially higher than that of either GaN or ZnO. The evolution of H2 and O2 is confirmed during photoelectrolysis at +0.5 V vs. Ag/AgCl. The efficiency of photoelectrolysis is found to decrease with irradiation time due to degradation of the electrode.

Pulse wave velocity (PWV) is useful for the evaluation of aortic stiffness. The brachial-ankle PWV (baPWV)and carotid PWV (from heart to carotid) were compared to study the relation of these two types of PWVs to diabetic complications in patients with type 2 diabetes mellitus.