Surface-enhanced light harvesting over MOF-derived porous ZnO films for highly efficient QDs-based photoelectrochemical hydrogen generation

Rational design of porous metal oxide films that serve as not only the scaffolds for light absorbers but also the transfer layer of photogenerated charges is essential for fabricating highly efficient photoanodes for photoelectrochemical (PEC) hydrogen generation. In this work, we report a facile one-step pyrolysis method which can convert Zn-based MOF to porous ZnO (m-ZnO) with rough surface and abundant oxygen vacancies (O_v). When incorporating core-shell quantum dots (QDs) as the light absorbers, the obtained photoanodes (m-ZnO@QDs) achieved outstanding PEC performance for hydrogen generation, exhibiting 1.6 times and 5.8 times higher saturated photocurrent density (J_sc) than those of conventional TiO₂@QDs and ZnO@QDs photoanodes, respectively. Comprehensive optical and electrochemical measurements reveal that the rough surface of m-ZnO can significantly improve the light-harvesting capacity of corresponding photoanodes through surface-enhanced light scattering. Moreover, the O_v in m-ZnO facilitate the interfacial transfer of photogenerated electrons. Our findings indicate that the MOFs are valuable precursors for the preparation of porous films, offering a promising route to develop high-performance QDs-based PEC devices.