Modification effects of an expanded porphyrin on the photocatalytic activity of gallium zinc oxynitride (GaN:ZnO) were investigated. The expanded porphyrins, which have more than four pyrrole units in its structure, were successfully synthesized one pot reaction. Morecule structures of the expanded porphyrins are shown in Figure 1.Figure 1. Molecure structures of the expanded porphyrins used in this study.The photocatalytic activity of GaN:ZnO catalysts is improved by dye modification. Among the expanded porphyrins examined, dye-3 (hexaphyrin) is the most effective for improving water-splitting activity, and the formation rates of H2 and O2 achieved values of 0.92 and 0.45 mmol g-1 h-1, respectively (Table 1).Photoluminescence (PL) spectra of GaN:ZnO catalysts suggested that excitation energy was transferred from GaN:ZnO to porphyrins. Unlike the dye sensitization, the excitation energy of GaN:ZnO transferred to the porphyrin dyes in this photocatalyst system. This study indicates that the surface modification of an expanded porphyrin has a potential to improve the photocatalytic activity of inorganic semiconductor photocatalysts.

Photocatalytic water splitting on GaN:ZnO modified with expanded porphyrin for solar energy harvesting

246th National Meeting (2013)

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