Metal-organic Framework-Derived CoSx/NiS Co-Decorated Heterostructures: Toward Simultaneous Acceleration of Charge Carrier Separation and Catalytic Kinetics

Designing semiconductor-based heterojunctions for achieving high-efficiency electron-hole separation and rapid catalytic kinetics is highly important for promoting photo electrochemical water oxidation performance. Herein, we synthesize a dual-cocatalyst-decorated heterostructure (TiO2/CdS/CoSx/ NiS) via in situ metal-organic framework (MOF) derivation. The homogeneous dispersion of CoSx/NiS, benefiting from the MOF derivation of atomic metal building blocks, significantly accelerates the catalytic kinetics and decreases the overpotential of the water oxidation process. Meanwhile, the CoNi MOF-derived TiO2/CdS heterojunctions simultaneously improve the electron-hole separation and extend the absorption range due to the formation of an oriented electromagnetic field and narrow bandgap of CdS. The as-prepared TiO2/CdS/CoSx/NiS exhibits excellent performance toward photoelectrochemical water oxidation with a photocurrent density of up to 5.10 mA/cm2. The practical production rate of O2 is about 22.25 mu mol-h-1-cm-2, which is higher than those of TiO2/CoNi-MOF (18.69 mu mol-h-1-cm-2) and bare TiO2 (13.80 mu mol-h-1-cm-2). This study offers a promising solution to tailor the growth and dispersion of high-quality dual-cocatalysts and paves the way toward the commercial realization of water-splitting systems.

Automated summary

The design and synthesis of semiconductor-based heterojunctions with dual-cocatalyst decoration is crucial for achieving efficient electron-hole separation and catalytic kinetics in photoelectrochemical water oxidation. The in situ metal-organic framework (MOF) derivation method was used to synthesize a TiO2/CdS/CoSx/NiS heterostructure, which exhibited excellent performance in terms of photocurrent density and practical production rate of O2.