Rational design of hierarchical nanocomposites is a promising approach for efficient energy harvesting and conversion. A noble-metal-free ternary hierarchical composite, Cd0.5Zn0.5S-g-C3N4-MoS2, has been developed. Materials were chosen based on their relative band-edge alignments and they were studied as a composite for photocatalytic properties. The photocatalytic activity was evaluated by measuring the rate of photodriven H2 evolution with concomitant degradation of organic pollutants, such as Rhodamine B. Optimization of the loading of g-C3N4 and MoS2 onto Cd0.5Zn0.5S results in an enhanced yield of hydrogen evolution by ∼120% (Cd0.5Zn0.5S-g-C3N4) and ∼197% (Cd0.5Zn0.5S-g-C3N4-MoS2) compared to bare Cd0.5Zn0.5S. The ternary hybrid, Cd0.5Zn0.5S-g-C3N4-MoS2 resulted in an apparent quantum yield (AQY) of 38% at 420 nm. The significant improvement in photocatalytic performance in the composite can be attributed to enhanced interfacial charge transfer of electrons from g-C3N4 to Cd0.5Zn0.5S and MoS2. We surmise that the close proximity of the energies of conduction band edge for each component in the ternary composite promotes better charge separation.

A composite photocatalyst of Cu2ZnSnS4 (CZTS) containing 1% MoS2 is prepared by hydrothermal reaction using Cu(OAc)2, Zn(NO3)2, and SnCl2 in a H2O/en (9:1) solution to which SC(NH2)2 is added dropwise (autoclave, 180 °C, 24 h).

Noble metal-free counter electrode using a co-catalytic loading of MoS2 nanosheets to Cu2ZnSnS4 microspheres are investigated by means of CuInS2-CdSe quantum dot (QD) co-sensitized solar cells fabricated with single crystalline ZnO nanowires. An ex situ electrophoretic deposition route is employed to deposit QDs onto ZnO nanowires that are epitaxially grown on ZnO seed layered FTO substrates. Hydrothermally grown ZnO nanowires have also established an excellent stability against the bias conditions applied to fabricate the photoanodes of the devcies. The superior photovoltaic performance of CuInS2-CdSe QD co-sensitized cells are compared with that of bare CuInS2 and CdSe counterparts, using current-voltage and incident photon-to-current conversion efficiency measurements. The present study also demonstrates an enhanced performance of the devices fabricated with 1.0 wt % of MoS2 loaded Cu2ZnSnS4 basaed counter electrodes in contrast to bare Cu2ZnSnS4. Hydrothermal loading of MoS2 to Cu2ZnSnS4 generates an electrically interconnected network of Cu2ZnSnS4 microspheres, leading to a facile charge transport in the counter electrode of the devices. MoS2 in its nanosheet form acts as an electrical bridge that interlinks the Cu2ZnSnS4 microspheres. Additionally, a favorable band energy alignment of Cu2ZnSnS4 and MoS2 stimulates the charge transfer dynamics in Cu2ZnSnS4-MoS2 composite. Electron transport and recombination kinetics of the devices are measured using electrochemical impedance spectroscopy.devices revealed an additional benefit of direct 1D electrical

To the best of our knowledge this is the first report in which ruthenium doped polycrystalline lanthanum manganite, LaMnRuO (x = 0.0-0.4), having high efficacy for oxygen production from water without the use of any sacrificial reagent or co-catalyst and as an efficient photocatalyst for dye degradation is reported. Ruthenium doping alters the crystal structure of the parent LaMnO (LMO) due to the induced chemical pressure of the larger Ru ion, which facilitates a bond angle of 180° in the Mn-O-Mn plane resulting in the easy extraction of a photo-generated charge carrier population leading to enhanced photocatalytic activity. Rietveld refinements reveal that the parent compound LMO crystallizes in the rhombohedral phase, while upon an increase in the doping concentration of ruthenium, the phase of the compounds changes from the rhombohedral to the cubic phase. The percentage contribution of each phase has been estimated using the sixth-order polynomial and pseudo-Voigt function. Typically, all the compositions, LaMnRuO (x = 0.0-0.4), were prepared by a conventional solid state route and studied for their photocatalytic activity. The synthesized compounds were investigated by powder X-ray diffraction (PXRD), UV-visible diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) analysis. The structure-property correlation of the compound is presented based on Rietveld refinement combined with the experimental data. The as-prepared compounds show efficient photocatalytic oxygen gas production from water without the use of any co-catalyst or sacrificial reagents. Among the five compositions, LaMnRuO shows the highest O production efficiency (4.73 mmol g h) with an apparent quantum yield (AQY) of 7.43%. These ruthenium doped compositions also exhibit superior dye degradation properties, studied by taking the industrial dye methyl orange (MO) as the model compound.

One of the major limiting factorsf or efficient photoelectrochemical water oxidation is the fast recombination kinetics of photogenerated charge carriers. Herein,w ep ropose am odel system that utilizes ZnIn 2 S 4 and hierarchical VS 2 microflowersf or efficient charge separation through aZscheme pathway,w ithoutt he need for an electron mediator. An impressive 18-fold increase in photocurrent was observed for ZnIn 2 S 4 -VS 2 compared to ZnIn 2 S 4 alone. The charge-transfer dynamics in the composite were found to follow aZ -scheme pathway,w hich resulted in decreased charger ecombination and greater accumulation of the surface charge. Furthermore, slow kinetics of the surfacer eaction in the ZnIn 2 S 4 -VS 2 composite correlated to an increased surface-charge capacitance. This feature of the composite materialf acilitated partial storage of the photogenerated chargec arriers (e À /h + + )u nder illumination andd ark-current conditions, thus storing and utilizing solar energy more efficiently.