Interplay between Mesocrystals of CaTiO3 and Edge Sulfur Atom Enriched MoS2 on Reduced Graphene Oxide Nanosheets: Enhanced Photocatalytic Performance under Sunlight Irradiation

In this work, an attempt has been made to strategically and systematically design novel and multifunctional nanocomposite photocatalysts by coupling mesocrystals of CaTiO3 with edge-sulfur-atoms-enriched MoS2 and reduced graphene oxide (RGO) nanosheets. A remarkable enhancement in photocatalytic activity could be evidenced with an optimized content (20 %) of MoS2-RGO nanosheets coupled with CaTiO3 mesocrystals. This nanocomposite showed a 33-fold enhanced photocatalytic hydrogen evolution in comparison to bare CaTiO3, with apparent quantum efficiencies of 5.4 %, 3.0 % and 17.7 % at 365, 420 and 600 nm monochromatic wavelengths. In addition, the excellent adsorptive degradation of different organic pollutants was also achieved with these photocatalysts, which revealed their multifunctional behavior. The enhanced photocatalytic performance can be accredited mainly to following factors: (i) Intimate contact between constituent materials and efficient charge transfer across the ternary heterojunction, which suppresses photogenerated charge recombination; (ii) The high surface area provides abundant sites for reactant adsorption and further reaction; (iii) Defect-rich MoS2 with sulfur atoms on the exposed edges provide sticky sites for H+ ions and hence enhance the hydrogen generation. The design strategy employed in this work can be adopted to improve the properties and performance of other mesocrystals, which can lead to the fabrication of low-cost and multifunctional catalysts for diverse applications.