Solar-light-driven photocatalytic hydrogen evolution by push-pull thiophenoxy-substituted zinc phthalocyanines

Two zinc phthalocyanine derivatives (ZnPc 1 and 2) carrying bulky 2,6-diisopropylthiophenoxy peripheral substituents have been synthesized and their performances as photosensitizers in photochemical hydrogen production evaluated. To examine the influence of the spacer on the performance of ZnPc 1 and 2, the carboxyl group has been linked to the macrocycle ring either directly or via the phenyl ring, respectively. The photocatalytic activities of ZnPcs (ZnPc 1 and ZnPc 2) as sensitizers of TiO(2 )for hydrogen production were investigated in the presence of Pt. ZnPc 1 and ZnPc 2 sensitized TiO(2 )produced 0.687 mmolg(-1)h(-1) and 0.436 mmol g(-1)h(-1) hydrogens, which also reached 3.986 and 2.091 mmolg(-1) after 8h illumination, respectively, under visible light (>= 420 nm) irradiation. In addition, STH efficiencies of ZnPc 1/TiO2 and ZnPc 2/TiO2 were determined as 1.77% and 1.12%, respectively. ZnPc 1/TiO2 exhibited 1.9-fold more photocatalytic hydrogen amount than ZnPc 2/TiO2, and the hydrogen evolution performance of the photocatalyst in the presence of Pt enhanced to 3.021 mmol g(-1)h(-1) and 0.911mmol g(-1)h(-1) for ZnPc 1 and ZnPc 2, respectively.

Automated summary

Two zinc phthalocyanine derivatives carrying bulky peripheral substituents have been synthesized and their performances as photosensitizers in photochemical hydrogen production evaluated. The results showed that ZnPc 1 exhibited better performance compared to ZnPc 2, and the presence of Pt enhanced the hydrogen production performance of the photocatalyst.