ABSTRACT
Bimetallic zeolite-imidazole frameworks with controllable flat band position, band gap and hydrogen evolution reaction characteristics were adopted as a photocatalytic hydrogen production catalyst. Furthermore, the g-C3N4-MoS2 2D-2D surface heterostructure was introduced to the ZnM-ZIF to facilitate the separation as well as utilization efficiency of the photo-exited charge carriers in the ZnM-ZIFs. On the other hand, the ZnM-ZIFs not only inhibited the aggregation of the g-C3N4-MoS2 heterostructure, but also improved the separation and transport efficiency of charge carriers in g-C3N4-MoS2. Consequently, the optimal g-C3N4-MoS2-ZnNi-ZIF exhibited an extraordinary photocatalytic hydrogen evolution activity 214.4, 37.5, and 3.7 times larger than that of the pristine g-C3N4, g-C3N4-ZnNi-ZIF and g-C3N4-MoS2, respectively, and exhibited a H2-evolution performance of 77.8 µmol h-1 g-1 under UV-Vis light irradiation coupled with oxidation of H2O into H2O2. This work will furnish a new MOF candidate for photocatalysis and provide insight into better utilization of porous MOF-based heterostructures for hydrogen production from pure water.
ABSTRACT
The g-C3N4-MoS2-M(OH)x ternary heterostructures were designed and fabricated for the first time. The embedding of noble-metal-free MoS2-M(OH)x dual cocatalysts over g-C3N4 nanosheets led to obvious synergistic effect for improving the transport as well as utilization efficiency of photo-generated charge carriers. Consequently, the optimal ternary heterostructure (g-C3N4-MoS2-Ni(OH)2) exhibited photocatalytic hydrogen production activity 4.5 times larger than the sum of the photocatalytic HER activity of g-C3N4-MoS2 and g-C3N4-Ni(OH)2. More significantly, even in the absence of the sacrificial agent, the g-C3N4-MoS2-Ni(OH)2 ternary heterostructure exhibited a photocatalytic HER activity of 0.3 mmol h-1 g-1 with considerable H2O2 production under UV-visible light.
ABSTRACT
Metal-organic framework-templated g-C3N4-NiCoP2-porous carbon (PC) ternary hybrid nanomaterials were designed by taking full advantage of the metal-organic framework (MOF) derivative in the photocatalytic reaction for the first time. The MOF-templated porous structure could prevent the stacking of the carbon nitride nanosheet, and the carefully designed NiCoP2, possessing low electrocatalytic hydrogen evolution reaction (HER) overpotential and flat-band potential, could improve the separation as well as the utilization efficiency of photogenerated electron-hole pairs. Moreover, the ligand-templated porous carbon, acting as an interface mediator between g-C3N4 and the NiCoP2 cocatalyst, could boost the charge carrier transport. Consequently, the optimal ternary g-C3N4-NiCoP2-PC heterostructure exhibited enhanced photocatalytic HER performance and considerable H2 evolution performance of 5.8 µmol/h/g under UV-visible light with stoichiometric H2O2 production even in pure water. This work took full advantage of the MOF derivative for improving the photocatalytic reaction activity and provided a method that can hopefully help in designing a novel high-performance catalyst for solar conversion.
ABSTRACT
A hybrid of ZIF-8 with CdS nanorods could increase the transport efficiency of photo-generated charge carriers and the surface area. Notably, through doping Zn ions with a transition metal, in this work, we fabricated a bimetallic ZnM-ZIF (M = Ni, Cu, or Co)-encapsulated CdS nanorod heterostructure for the first time. Compared with ZIF-8, the bimetallic ZIF exhibited a modulated structure, flat band position, and lower overpotential for the hydrogen evolution reaction. ZnM-ZIF not only improved the transfer of water and light, but also boosted the separation of charge carriers. Consequently, the optimized CdS-ZnM-ZIF samples with Cu, Ni, and Co doping showed corresponding photocatalytic hydrogen activities 44, 92, and 59 times larger than that of pristine CdS nanorods. This work provides a new method for better utilization of porous MOF crystals for photocatalysts.
ABSTRACT
Nanoporous Co-doped Zn1-xCdxS were facilely fabricated via adopting ZIFs as templates, and Cd(NO3)2 and thiourea as precursors. The highly porous microstructure and uniform Co-doping of the photocatalyst afford a high H2-production rate (45.2 and 422.2 times larger than those of Zn0.5Cd0.5S and CdS), providing an effective way for the development of high performance nanoporous photocatalysts.
