3D network-like rGO-MoSe2 modified g-C3N4 nanosheets with Z-scheme heterojunction: Morphology control, heterojunction construct, and boosted photocatalytic performances

The transition-metal dichalcogenides (TMDs) is a promising photocatalyst for degrading contaminant, while limited active sites and poor carrier mobility are the primary challenges for improving photocatalytic degrading efficiencies in both bare TMDs and TMDs-based photocatalysts. A rGO-MoSe2 composite with 3D network hierarchical structure was fabricated by the GO-assisted solvothermal method. And then rGO-MoSe2/g-C3N4 3D/2D hierarchical structures were constructed by combining rGO-MoSe2 with g-C3N4 nanosheets. The optimal rGO-MoSe2/g-C3N4 composite exhibited the highest photocatalytic degrading rate of 97.4% towards RhB under simulated solar light, and its pseudo-first-order apparent rate constant (k) was 0.0715 min(-1), being 5.9 and 12.5-folds higher than that of MoSe2/g-C3N4 (0.0121 min(-1)) and bare g-C3N4 (0.00573 min(-1)), respectively. The 3D/2D hierarchical structure endow rGO-MoSe2/g-C3N4 composite with the improved light-harvesting and abundant active sites, supported by the DRS and BET analyses. And rGO nanosheets could act as efficient transfer and separation channels for electron-hole pairs between MoSe2/g-C3N4, confirmed through the photocurrent response and EIS tests. According to the results of DRS spectra and Mott-Schottky plots, the spatial behavior of photo-induced carriers at interface of rGO-MoSe2/g-C3N4 would comply to a Z-scheme transfer pathway under the synergy effects of the internal electric field and band bending. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Transition-metal dichalcogenides (TMDs) exhibit promising photocatalytic performance for degrading contaminants, but limited active sites and poor carrier mobility are the main challenges. In this study, a 3D/2D hierarchical structure rGO-MoSe2/g-C3N4 composite was successfully synthesized and showed high photocatalytic degrading efficiency towards RhB under simulated solar light.