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.

The synthesis of orthorhombic nitrogen-doped niobium oxide (NbON) nanostructures was performed and a photocatalytic study carried out in their use in the conversion of toxic HS and water into hydrogen under UV-Visible light. Nanostructured orthorhombic NbON was synthesized by a simple solid-state combustion reaction (SSCR). The nanostructural features of NbON were examined by FESEM and HRTEM, which showed they had a porous chain-like structure, with chains interlocked with each other and with nanoparticles sized less than 10 nm. Diffuse reflectance spectra depicted their extended absorbance in the visible region with a band gap of 2.4 eV. The substitution of nitrogen in place of oxygen atoms as well as Nb-N bond formation were confirmed by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. A computational study (DFT) of NbON was also performed for investigation and conformation of the crystal and electronic structure. N-Substitution clearly showed a narrowing of the band gap due to N 2p bands cascading above the O 2p band. Considering the band gap in the visible region, NbON exhibited enhanced photocatalytic activity toward hydrogen evolution (3010 μmol h g) for water splitting and (9358 μmol h g) for HS splitting under visible light. The enhanced photocatalytic activity of NbON was attributed to its extended absorbance in the visible region due to its electronic structure being modified upon doping, which in turn generates more electron-hole pairs, which are responsible for higher H generation. More significantly, the mesoporous nanostructure accelerated the supression of electron and hole recombination, which also contributed to the enhancement of its activity.

Unique honeycomb layered 2D MoS2 nanostructures and hierarchical 3D CdMoS4 marigold nanoflowers demonstrated by facile template free solvothermal method for solar H2 production.

Herein, we demonstrated a green approach for the synthesis of high surface area (850 m g) mesoporous perforated graphene (PG) from Bougainvillea flower for the first time using a template free single-step method. The existence of PG was confirmed by XRD, Raman spectroscopy, FESEM, and FETEM. Surprisingly, FETEM clearly showed 5-10 nm perforation on the graphene sheets. More significantly, these mesoporous perforated graphene sheets can be produced in large scale using the present green approach. Considering high surface area and unique perforated graphene architecture, these PGs were studied for supercapacitor applications in detail without any chemical or physical activation. The nanoporosity and high conductivity of PG derived from Bougainvillea flower exhibited excellent supercapacitive performance. According to the supercapacitor study, the synthesized perforated graphene sheets conferred a very high specific capacitance of 458 F g and an energy density of 63.7 Wh kg at the power density of around 273.2 Wh kg in aqueous 1 M NaSO. Significantly, the areal capacitance of PG was observed to be very high, i.e. 67.2 mF cm. The cyclability study results showed excellent stability of synthesized perforated graphene sheets up to 10 000 cycles. Note that the specific and areal capacitance and the energy density of the synthesized PGs are much higher than the earlier reported values. The high supercapacitive performance may be due to high surface area and mesoporosity of PG. The present approach has a good potential to produce cheaper and high surface area PG. These PGs are good candidates as an anode material in the lithium-ion battery.