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 H₂ generation rate obtained is 39.5 µmol h⁻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.