Enhanced visible-light-assisted photocatalytic hydrogen generation by MoS2/g-C3N4 nanocomposites

• Published in: International journal of hydrogen energy Vol. 45; no. 15; pp. 8497 - 8506
• Main Authors: Nagaraja, C.M., Kaur, Manjodh, Dhingra, Suman
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 18.03.2020
• Subjects: Dye-sensitized; Graphitic carbon nitride; H2 generation; Molybdenum disulfide; Visible-light photocatalysis; Dye-sensitized; Molybdenum disulfide; H2 generation; Visible-light photocatalysis; Graphitic carbon nitride
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2020.01.042

A facile, one-pot, solvothermal synthesis of MoS2 microflowers (S1) and the heterostructures MoS2/g-C3N4 with varying ratios of 1:1 (S2), 1:2 (S3) and 1:3 (S4) exhibiting enhanced visible-light-assisted H2 generation by water splitting has been reported. The compounds were thoroughly characterized by PXRD, FESEM, HRTEM, EDS, UV–vis and XPS techniques. FESEM and HRTEM analyses showed the presence of microflowers composed of nano-sized petals in case of pure MoS2 (S1), while the MoS2 microflowers covered with g-C3N4 nanosheets in case of MoS2/g-C3N4 heterostructure, S4. XPS analysis of S2 showed the presence of 2H phase of MoS2 with g-C3N4. The Eosin-Y/dye-sensitized visible-light-assisted photocatalytic investigation of the samples in the absence of any noble metal co-catalyst revealed very good water splitting activity of MoS2/g-C3N4 heterostructure, S2 with hydrogen generation rate of 1787 μmol h−1g−1 which is about 6 and 40 times higher than pure MoS2 and g-C3N4 respectively. The relatively higher catalytic activity of the heterostructure, S2 has been ascribed to the efficient spatial separation of photo-induced charge carriers owing to the synergistic interaction between MoS2 and g-C3N4. A possible mechanism for the Eosin-Y-sensitized photocatalytic H2 generation activity of MoS2/g-C3N4 heterostructures has also been presented. The enhanced activity of S2 was further supported by fluorescence measurements. Thus, the present study highlights the importance of non-noble metal based MoS2/g-C3N4 heterojunction photocatalysts for efficient visible-light-driven H2 production from water splitting. A facile solvothermal synthesis of MoS2 nanosheets (S1) and MoS2/g-C3N4 heterostructures with varying ratios of 1:1 (S2), 1:2 (S3) and 1:3 (S4) is reported. The visible light assisted photocatalytic investigation of the samples in the absence of noble metal co-catalyst revealed very good water splitting activity of the heterostructure, S2 with hydrogen generation rate of 1787 μmolh−1g−1, which is found to be higher than those of pure MoS2 and g-C3N4 compounds. The relatively higher catalytic activity of S2 has been attributed to the synergistic effect of MoS2 and g-C3N4 and the presence of highly reactive edge sites of MoS2. Furthermore, the plausible mechanism for the formation of MoS2 nanosheets and MoS2/g-C3N4 heterostructures along with their water splitting activity has been presented. [Display omitted] •Facile synthesis of MoS2/g-C3N4 heterostructures is reported.•The MoS2/g-C3N4 (1:1) exhibits visible-light-driven H2 generation of 1787  μmol h−1g−1.•The heterostructure shows higher H2 generation activity over the parent materials.