Efficiently visible-light-induced photoactivity of MoS2 nanoflowers/chromic oxide/protonated titanate nanoflakes edge-on ternary heterostructures for production of hydrogen

Highlights: • The MoS₂ nanoflowers/Cr₂O₃/TNFs were prepared via solvothermal-assistance route. • The Cr-TNFs could fully contact with the active edges of MoS₂. • The photo-induced electrons could pass through MoS₂ and reach the active edge sites. • The 0.5%Cr-TM (20 wt.% of MoS₂) shown optimum H₂ production rate of 217 μmol h^-1 g^-1. • The cyclic tests demonstrated the stability and recycling performance. The edge-on ternary heterostructured composite of MoS₂ nanoflowers/chromic oxide/protonated titanate nanoflakes (Cr-TM) with different amounts of chromic oxide (Cr₂O₃) nanoparticles is prepared via solvothermal method. A layered structure of nanoflowers obtained as Cr₂O₃/protonated titanate nanoflakes (Cr-TNFs) form good contact with the active edges of MoS₂. The analysis of XPS results indicate the existence of coupled electron orbits which is attributed to the formation of TiOMo bonds at interface between Cr-TNFs and MoS₂, and stabilization of loaded Cr₂O₃ on the titanate nanoflakes (TNFs). The as-prepared Cr-TM composites exhibit overall enhancement in visible-light response as well as characteristic absorption of Cr₂O₃. The MoS₂ plays the role of co-catalyst to improve the interfacial transfer efficiency of the photogenerated electrons, and accelerate the transport and separation of in-layered holes. The results of visible-light-driven photocatalytic H₂ production test indicate that the H₂ production rate of Cr-TM (20 wt.% of MoS₂) is optimum, giving a relatively high H₂ generation rate of 217 μmol h^-1 g^-1 for 0.5%Cr-TM. The MoS₂/Cr₂O₃/titanate heterostructure show a good synergism with MoS₂ co-catalyst under visible light, as a result photo-induced electrons pass through MoS₂ basal planes and reach the active edge sites, participating in the proton-reduction reaction. The cyclic tests demonstrated outstanding stability and recycling performance of samples as well as good contact of MoS₂ nanoflowers with the TNFs.