Maximizing the photocatalytic hydrogen evolution of Z-scheme UiO-66-NH2@Au@CdS by aminated-functionalized linkers

The Z-scheme photocatalysts with matched rates for reduction and oxidation half reactions benefit from the advantages of efficient light harvesting and effective separation of electron-hole pairs, which can maximize the water splitting performance. However, the 4-electron reaction and the slow transfer of holes render the oxidation reaction upon oxygen evolution photocatalyst to be the rate-determining step. Herein, we report on promoting the oxidation reaction in UiO-66-NH2@Au@CdS Z-scheme photocatalysts by using the aminated-functionalized linker bdc-NH2. Compared with pristine UiO-66 MOFs, UiO-66-NH2 not only extends the light harvesting range but also offers the high oxidation reaction performance matched with photocatalytic hydrogen generation. As a result, the highest H-2 generation rate obtained is 39.5 mu molh(-1), which is 2.18 times higher than that of the Z-scheme photocatalysts constructed by UiO-66. The present work clearly shows the essential importance in tuning the oxidation capacity of photosystem II in constructing Z-scheme photocatalysts for maximizing the water splitting.