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Promoting the charge separation to improve photocatalytic performance of semiconductor photocatalysts is very important in the field of artificial photosynthesis. Here, a novel MoS2/CdS 2D–2D ultrathin nanosheet heterostructure was fabricated via a one-pot solvothermal route. The obtained 2D–2D MoS2/CdS nanojunction has not only provided large contact areas, but also shortened the charge-transport distance, resulting in significantly enhanced photocatalytic H2 evolution property. By optimizing the 2D MoS2 amounts in the heterojunction, the 5 wt% 2D/2D MoS2/CdS heterojunction displayed the maximal photocatalytic H2 evolution rate of 5566 μmolh−1 g−1 under visible-light irradiation in the presence of lactic acid as the sacrificial reagent, which was 10.1 times higher than that of pristine 2D CdS (516 μmolh−1 g−1). Based on the photoelectrochemical and photoluminescence spectra tests, it could be deduced that the charge separation and transfer of 2D/2D MoS2/CdS heterojunction were tremendously improved, and the recombination of photoinduced electron–hole pairs was effectively impeded. Moreover, the 2D MoS2 was used as a co-catalyst to provide the abundant active sites and lower the overpotential for H2 generation reaction. The current work would offer an insight to fabricate the 2D/2D heterojunction photocatalysts for splitting H2O into H2. [ABSTRACT FROM AUTHOR]

For eco-friendly, economic, and renewable energy source, dye-sensitized solar cell (DSSC) has attracted extensive attention in current era. DSSC faces various researches toward the enhancement of its efficiency. Developing high-performance photoanode for efficient DSSCs is urgent need and it is still under research. In this regard, we successfully synthesized 2D graphene-decorated WSe2 by simple hydrothermal approach. The synthesized photoanode materials were characterized by advanced technique such as XRD, SEM, TEM, EDAX, PL, and XPS to investigate their size, morphology, crystalline phase, structure, chemical nature, and purity. The XRD results exposed the hexagonal cubic phase of WSe2. The different morphologies like spherical and 2D sheet were confirmed for WSe2, graphene through SEM micrograph which was further confirmed by TEM. The EDAX and XPS results proved the purity of composite photoanode and W+6 and W+4 state of tungsten in composite, respectively. UV and PL results confirmed the improved optical properties and reduced band gap during graphene incorporation. The surface area and pore size of WSe2/graphene composite was determined using N2 absorption–desorption measurements and found to be 105.2 m2/g and 19.8 nm, respectively, which is higher than that of pristine WSe2 (86.3 m2/g; 34.2 nm). DSSCs have been fabricated with these materials such as WSe2, RGW1, RGW2, and RGW3 as photoanodes. A device containing 10 wt% of 2D graphene-incorporated hybrid material exhibits significant improvements over the pure counterpart, due to less recombination of photo-generated electrons, rapid charge collection, and higher dye sensitization. The 2D graphene-decorated WSe2hybrid material as photoanode thus offers a promising low-cost Pt-free counter electrode for DSSC. [ABSTRACT FROM AUTHOR]