NHE (pH = 0) or E CB = −50 mV (pH = 7), which disfavors its photoexcited electrons to efficiently achieve reduction of CO 2 towards the key intermediate CO 2 −. Moreover, the conduction band (CB) edge of TiO 2 is E CB = −160 mV vs.
However, the large energy gap of TiO 2 (3.2 eV) limits its photoactivity exclusively in the ultraviolet radiation range, typically λ < 360 nm, which accounts for 2–5% of the sunlight. So far, TiO 2 remains the most studied photocatalyst, due to its chemical stability, low cost, and availability. Moreover, research interest in photocatalytic and photo-electrochemical applications has increased, prompting successful engineering of various semiconducting photocatalysts. In this context, herein we discuss examples and synthesis efforts that aim to clarify the role of interfaces, faces, and phase stability under photocatalytic conditions.įujishima and Honda in 1972,, paved the way for light-induced water splitting by TiO 2 and, since then, numerous studies on photocatalysts were presented, and in particular TiO 2.
Distinction between the role of various factors is required to protect the material from photocorrosion, e.g., use of hole scavengers/electron acceptors, band-gap engineering, nano-facet engineering, and selectivity of CO 2-reduction pathways, to name a few possible solutions. Converging literature evidence shows that, because of photocorrosion, single-phase Cu-oxides would not be favorable to be used as a standalone cathodic catalyst/electrode however, their heterojunctions and the coupling with proper partner materials is an encouraging approach. In the present review, we discuss aspects interlinking the stability under photocorrosion of the (CuO/Cu 2O/Cu 0) nanophase equilibria, and performance in H 2-production/CO 2-reduction. The highly reducing conduction band edge of the d-electrons in Cu 2O dictates its efficiency towards CO 2 reduction under sunlight excitation. Cu-oxide nanophases (CuO, Cu 2O, Cu 0) constitute highly potent nanoplatforms for the development of efficient Artificial Photosynthesis catalysts.
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