Bimetallic zeolite-imidazole framework-based heterostructure with enhanced photocatalytic hydrogen production activity.

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.

Toward enhanced photocatalytic activity of graphite carbon nitride through rational design of noble metal-free dual cocatalysts.

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.