UiO-66-NH2 Metal-Organic Frameworks with Embedded MoS2 Nanoflakes for Visible-Light-Mediated H2 and O2 Evolution.

Abstract

Hydrogen evolution from water splitting by means of a photocatalytic approach is an ideal future energy source and free of fossil reserves, in contrary photocatalytic O2 evolution remains a bottleneck due to high over potential and low efficiency. For reasonable use of solar light, photocatalysts must be sufficiently stable and efficient toward harvesting of sunlight from both theoretical and practical viewpoints. In this regard, here we have prepared MoS2-modified UiO-66-NH2 MOF through a facile hydrothermal technique and evaluated its efficiency toward photocatalytic H2 and O2 evolution by water splitting in the presence of sacrificial agents. A couple of similar type of analyses have been studied previously; however, this analysis represents a diverse scientific approach on the basis of interfacial contact toward reveal the actual potential of nanoflakes MoS2 as well as UiO-66-NH2. In this regard the as-synthesized photocatalyst was well-characterized by XRD, FTIR, UV-vis diffuse reflectance spectra, FESEM, HRTEM, XPS, and BET analysis techniques, which provide sufficient evidence toward successful synthesis of the pristine materials and efficacious anchorage of MoS2 on the active surface of UiO-66-NH2 by the ionic interaction between Zr-O and S/Mo. Among the synthesized photocatalysts (3 wt %) MoS2/UiO-66-NH2 shows the optimum outcome toward H2 and O2 evolution, i.e., 512.9 μmol/h (4.37 times greater than bare UiO-66-NH2) and 263.6 μmol/h (4.25 and 11.32 times greater than bare UiO-66-NH2 and MoS2, respectively). The superior performance obtained by the composite is due to the synergistic effect of pristine UiO-66-NH2 and MoS2 which proceeds through a type-II interband alignment for the facile channelization of excitons. This investigation will bestow a beneficial blue-print to construct challenging photocatalysts and to find out the paramount performance toward photocatalytic water redox reaction.