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We have investigated an economical green route for the synthesis of a p-type N-doped ZnO photocatalyst by a wet chemical method. Significantly, hazardous H 2 S waste was converted into eco-friendly hydrogen energy using the p-type N-doped ZnO photocatalyst under solar light, which has previously been unattempted. The as-synthesized p-type N-doped ZnO shows a hexagonal wurtzite structure. The optical study shows a drastic shift in the band gap of the doped ZnO in the visible region (3.19-2.3 eV). The doping of nitrogen into the ZnO lattice is conclusively proved from X-ray photoelectron spectroscopy analysis and Raman scattering. The morphological features of the N-doped ZnO are studied from FESEM, TEM and reveal particle sizes to be in the range of ∼4-5 nm. The N-doped ZnO exhibits enhanced photocatalytic hydrogen generation (∼3957 μmol h −1 ) by photodecomposition of hydrogen sulfide under visible light irradiation, which is much higher as compared to semiconductor metal oxides reported so far. It is noteworthy that a green catalyst is investigated to curtail H 2 S pollution along with production of hydrogen (green fuel) using solar light, i.e., a renewable energy source. The green process investigated will have the potential to synthesize other N-doped metal oxides.

Herein,we have reported the simultaneous water splitting and lignin (biomass) degradationbyC, N and Sdoped ZnO nanostructured material.Synthesis of C, N and S-doped ZnO was achieved viacalcination of Bis-thiourea zinc acetate (BTZA) complex. Calcination of the complex at 500 o C results in formation of 10 C, N, and S-doping in mixed phase of ZnO/ZnS, while calcination at 600 o Cgives the single phase of ZnO with N and S doping which is confirmed by XRD, XPS and Raman spectroscopy. The band gap of the calcinedsamples was observed to be in the range of 2.83-3.08 eV.Simultaneous lignin (waste of paper and pulp mills) degradation and hydrogen(H 2 ) production via water splitting under solar light has been investigated which is hitherto unattempted. The utmost degradation of lignin was observed with the 15 sample calcined at 500 o Ci.e. C, N, S-doped ZnO/ZnS as compared to sample calcined at 600 o Ci.e. N and S doped ZnO. The degradation of lignin confer the formation of useful fine chemical as a by-product i.e. 1-Phenyl-3-buten-1-ol. However, excellent H 2 production i.e. 580, 584 and 643 µmole h -1 per 0.1g, was obtained for the sample calcined at 500, 550 and 600 o C, respectively. The photocatalytic activity obtained is much higher as compared to earlier reported visible light active oxide and sulfidephotocatalysts. The 20 reusability study shows good stability of the photocatalyst. The prima facie observations show that lignin degradation and water splitting is possible with the same multifunctional photocatalystwithout any scarifying agent.

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We report here a new ternary chalcogenide material, cadmium lanthanum sulfide (CdLa 2 S 4 ) produced using a facile hydrothermal method at 433 K. The effect of the solvent on the morphology of the CdLa 2 S 4 was demonstrated for the first time. The prima facie observations revealed the formation of highly crystalline hexagonal structures in the form of flowers in aqueous medium. The flowers comprise hexagonal columns $300 nm in diameter and 1-1.2 mm in length. All the hexagonal structures have a sharp tip with a cavity of 10 nm and are almost equal in size. The nanoprisms have an average base size of 35 nm with 35 nm edges, and the nanowires have a diameter of 10-15 nm; both were obtained in methanol. Crystal and electronic structure calculations were performed using the Vienna ab initio simulation package (VASP) based on density functional theory (DFT). Considering the band gap of pristine CdLa 2 S 4 in the visible region (2.3 eV), we have demonstrated CdLa 2 S 4 as a photocatalyst for the production of H 2 under solar light. Nanostructured CdLa 2 S 4 prisms gave the maximum hydrogen production, i.e. 2552 mmol h À1 . Being a stable ternary nanostructured metal sulfide (with nanohexagons, nanoprisms, nanowires), CdLa 2 S 4 may have other potential prospective applications in solar cells and optoelectronic devices.