@article {49621, title = {Multifunctional NiO/Ti3+-TiO2 for concurrent water reduction and glycerol oxidation to value added products by sunlight driven photocatalysis}, journal = {Journal of Materials Chemistry A}, volume = {13}, year = {2025}, month = {JAN}, pages = {2105-2120}, type = {Article}, abstract = {

The present work describes the synthesis of bifunctional-mesoporous-self-doped Ti3+ containing NiO/TiO2 photocatalysts for concurrent utilization of e- and h+ to produce H2 and value-added products (VAPs), respectively, from aqueous glycerol. UV-vis diffuse reflectance results and band gap analysis revealed an improved light absorption due to integration of Ni2+ with Ti3+/TiO2. Various electrochemical, PL and TRPL spectral analyses demonstrate p-n heterojunction formation between NiO and Ti3+-TiO2, which enhances charge separation and helps in achieving improved activity. HRTEM analysis of NiO/Ti3+-TiO2 nanocomposites revealed that NiO is highly dispersed on TiO2 with interfacial heterojunctions between them. XPS results demonstrate the partial reduction of Ti4+ to Ti3+ and Ni-Ti synergetic interaction in NiO/TiO2 to form NiO/Ti3+-TiO2 nanocomposites. EXAFS studies show that the Ni-O bond distance is similar to that of NiTiO3 suggesting electronic integration of components of the photocatalyst by forming a Ni2+-O-Ti3+/Ti4+ lattice network. Ni2+/Ti3+-TiO2 nanocomposites as a bifunctional photocatalyst exhibited significantly enhanced activity in H2 production and conversion of glycerol to VAPs, namely, glycolaldehyde, 1,3-dihydroxyacetone, and formic acid; formation of these products highlights not only oxidation, but also C-C cleavage of glycerol. The NiO/Ti3+-TiO2 photocatalysts fabricated in thin film form displayed higher photocatalytic efficiency than their powder counterpart. Among NiO/Ti3+-TiO2 nanocomposites NiT-3 exhibits the highest H2 yield at 15.62 mmol h-1 g-1, which is 38 times higher than that of bare TiO2. The enhanced photocatalytic activity is ascribed to the high charge carrier density, the synergistic interaction between Ni2+ and Ti3+-TiO2, formation of a p-n heterojunction at the interface between NiO and Ti3+-TiO2 and effective utilization of charge carriers for redox reactions.

}, issn = {2050-7488}, doi = {10.1039/d4ta06910b}, author = {Rajendran, Sivaraj and Saju, Simi and Mani, Sunesh S. and Asoka, Anantha Krishnan and Saha, Arindam and Arun, Pushkaran S. and Ghosh, Biplab and Mathew, Thomas and Gopinath, Chinnakonda S.} } @article {49446, title = {Multifunctional NiO/Ti3+{\textendash}TiO2 for concurrent water reduction and glycerol oxidation to value added products by sunlight driven photocatalysis}, journal = {Journal of Materials Chemistry A}, volume = {13}, year = {2025}, month = {JAN}, pages = {2105-2120}, type = {Article}, abstract = {

The present work describes the synthesis of bifunctional-mesoporous-self-doped Ti3+\ containing NiO/TiO2\ photocatalysts for concurrent utilization of e-\ and h+\ to produce H2\ and value-added products (VAPs), respectively, from aqueous glycerol. UV-vis diffuse reflectance results and band gap analysis revealed an improved light absorption due to integration of Ni2+\ with Ti3+/TiO2. Various electrochemical, PL and TRPL spectral analyses demonstrate p{\textendash}n heterojunction formation between NiO and Ti3+{\textendash}TiO2, which enhances charge separation and helps in achieving improved activity. HRTEM analysis of NiO/Ti3+{\textendash}TiO2\ nanocomposites revealed that NiO is highly dispersed on TiO2\ with interfacial heterojunctions between them. XPS results demonstrate the partial reduction of Ti4+\ to Ti3+\ and Ni{\textendash}Ti synergetic interaction in NiO/TiO2\ to form NiO/Ti3+{\textendash}TiO2\ nanocomposites. EXAFS studies show that the Ni{\textendash}O bond distance is similar to that of NiTiO3\ suggesting electronic integration of components of the photocatalyst by forming a Ni2+{\textendash}O{\textendash}Ti3+/Ti4+\ lattice network. Ni2+/Ti3+{\textendash}TiO2\ nanocomposites as a bifunctional photocatalyst exhibited significantly enhanced activity in H2\ production and conversion of glycerol to VAPs, namely, glycolaldehyde, 1,3-dihydroxyacetone, and formic acid; formation of these products highlights not only oxidation, but also C{\textendash}C cleavage of glycerol. The NiO/Ti3+{\textendash}TiO2\ photocatalysts fabricated in thin film form displayed higher photocatalytic efficiency than their powder counterpart. Among NiO/Ti3+{\textendash}TiO2\ nanocomposites NiT-3 exhibits the highest H2\ yield at 15.62 mmol h-1\ g-1, which is 38 times higher than that of bare TiO2. The enhanced photocatalytic activity is ascribed to the high charge carrier density, the synergistic interaction between Ni2+\ and Ti3+{\textendash}TiO2, formation of a p{\textendash}n heterojunction at the interface between NiO and Ti3+{\textendash}TiO2\ and effective utilization of charge carriers for redox reactions.

}, doi = {https://doi.org/10.1039/D4TA06910B}, author = {Rajendran, Sivaraj and Saju, Simi and Mani, Sunesh S. and Asoka, Anantha Krishnan and Saha, Arindam and Arun, Pushkaran S. and Ghosh, Biplab and Mathew, Thomas and Gopinath, Chinnakonda S.} }