New Insight on Carbon Dioxide‐Mediated Hydrogen Production**

Abstract

A new approach to hydrogen production from water is described. This simple method is based on carbon dioxide‐mediated water decomposition under UV radiation. The water contained dissolved sodium hydroxide, and the solution was saturated with gaseous carbon dioxide. During saturation, the pH decreased from about 11.5 to 7–8. The formed bicarbonate and carbonate ions acted as scavengers for hydroxyl radicals, preventing the recombination of hydroxyl and hydrogen radicals and prioritizing hydrogen gas formation. In the presented method, not yet reported in the literature, hydrogen production is combined with carbon dioxide. For the best system with alkaline water (0.2 m NaOH) saturated with CO 2 under UV‐C, the hydrogen production amounted to 0.6 μmol h −1 during 24 h of radiation.

Enhancing microbial CO2 electrocatalysis for multicarbon reduction in a wet amine‐based catholyte

“…However, the pH levels for both conditions remained in the neutral range (pH 6.9 to 7.4) during mCO2ER due to the buffering effect of the catholyte, which contained a mineral medium with KH 2 PO 4 (Figure S2). The reason is that the bicarbonate ions formed acted as scavengers for the hydroxyl radicals [24] . Cyclic voltammograms of both conditions during the period exhibited quinone‐like properties ( E m in water=+0.09~−0.26 V vs. NHE; Figure 2(B, C)) [25] .…”

“…The reason is that the bicarbonate ions formed acted as scavengers for the hydroxyl radicals. [24] Cyclic voltammograms of both conditions during the period exhibited quinone-like properties (E m in water = + 0.09~À 0.26 V vs. NHE; Figure 2(B, C)). [25] To evaluate the effect of the CO 2 absorbent in the catholyte medium, we observed the growth of R. sphaeroides as suspended cells in the catholyte and attached cells on the cathode (biofilm layer) separately (Figure 3(A)).…”