@article {47600, title = {Aqueous methanol to formaldehyde and hydrogen on Pd/TiO2 by photocatalysis in direct sunlight: structure dependent activity of nano-Pd and atomic Pt-coated counterparts}, journal = {ACS Applied Energy Materials}, volume = {4}, year = {2021}, month = {NOV }, pages = {13347-13360}, type = {Article}, abstract = {In the present investigation, facet-controlled Pd nanoparticles with nanocube (Pd-NC) and truncated octahedron (Pd-TO) morphologies, and their counterparts with half-a-monolayer of atomic Pt coated (0.5 theta(Pt)-Pd-NC and 0.5 theta(Pt)-Pd-TO) surfaces were prepared. All of them were characterized and evaluated as cocatalyst after supporting them on commercial titania (P25) (Pd-NC/P25, Pd-TO/P25, 0.5 theta(Pt)-Pd-NC/P25, and 0.5 theta(Pt)-Pd-TO/P25) under direct sunlight and/or one sun conditions for the oxidation of methanol to formaldehyde along with solar hydrogen production. Pd-NC/P25 shows higher activity for hydrogen generation compared to Pd-TO/P25; however, activity reversal occurs with the above cocatalysts, but, after Pt-coating with further enhanced activity. The highest conversion of methanol (0.2 mu mol/h.mg) to 100\% selective formaldehyde was observed with 0.5 theta(Pt)-Pd-TO/P25, while other catalysts show significantly lower methanol conversion in the following order: 0.5 theta(Pt)-Pd-TO/P25 > 0.5 theta(Pt)-Pd-NC/P25 > Pd-NC/P25 > Pd-TO/P25. Pt-coated on (111) facets of Pd-TO simulates the activity associated as that of Pt(111) facets and demonstrating the highest and facet dependent activity. The present study is truly in resonance with exploiting the surface properties for heterogeneous catalysis, and highlights that less than a monolayer of Pt is sufficient to simulate the activity as that of bulk Pt. It is worth exploring this concept to other metals and substrates too.}, keywords = {heterogeneous catalysis, Nanomaterials, Oxidation, Photocatalysis, surface modification}, issn = {2574-0962}, doi = {10.1021/acsaem.1c03080}, author = {Nalajala, Naresh and Salgaonkar, Kranti N. and Chauhan, Inderjeet and Mekala, Siva Prasad and Gopinath, Chinnakonda S.} } @article {48273, title = {Selective and generic photocatalytic oxidation of alcohol with Pd-TiO2 thin films: butanols to butanal/butanone with different morphologies of Pd and 0.5 theta(Pt)-Pd counterparts}, journal = {Chemistry-An Asian Journal}, volume = {18}, year = {2023}, month = {MAR}, type = {Article}, abstract = {

The present study reports on the photocatalytic oxidation of butanols to butanal/butanone using thin film form of facet-dependent nano-Pd supported on commercial TiO2 under one-sun condition and demonstrates the generic nature. Pd-nanocube (Pd-NC(100)), Pd-truncated octahedron (Pd-TO (100) and (111)), polycrystalline (Pd-PC), and their counterparts with half-a-monolayer Pt-coated on Pd (0.5 theta(Pt)-Pd)) have been used as co-catalyst. A potentially scalable thin film form of Pd/TiO2 photocatalyst, prepared by drop-casting method, has been employed to study oxidation of n-butanol, 2-butanol, and iso-butanol to corresponding aldehyde/ketone. 100\% selectivity is demonstrated to respective aldehyde/ketone with any catalyst used in the present study with varying degree of butanols conversion by NMR. 0.5 theta(Pt)-Pd-TO/TiO2 shows the highest conversion of 2-butanol to butanone (13.6\% in 4 h). Continuous 10 h of reaction with the most active 0.5 theta(Pt)-Pd-TO/P25 catalyst demonstrates 31\% conversion of 2-butanol to butanone, and catalyst recyclability has been demonstrated. The present protocol can be scalable to large scales to maximize the conversion in direct sunlight. Due to its generic nature, the current method can also be applied to many other alcohols and substrate molecules.

}, keywords = {energy conversion, Nanomaterials, Oxidation, Photocatalysis, Sustainability}, issn = {1861-4728}, doi = {10.1002/asia.202201239}, author = {Salgaonkar, Kranti N. and Kale, Sandip R. and Nalajala, Naresh and Mansuri, Sayana and Gopinath, Chinnakonda S.} } @article {49773, title = {Synthesis of Pd-integrated carbon Dot@TiO2 thin film for photocatalytic glycerol reforming reaction for producing hydrogen}, journal = {Chemistry-an Asian Journal}, volume = {20}, year = {2025}, month = {NOV}, type = {Article}, abstract = {

A series of thin-film photocatalysts comprising TiO2 modified with carbon dots (CDs) dispersed either with palladium (Pd-CD/TiO2) or nickel (Ni-CD/TiO2) were synthesized via solid-state and wet-impregnation methods. Morphological characterization (HR-TEM, SEM-EDS) confirmed the anatase phase of TiO2 and the atomic dispersion of metal-integrated CDs on its surface. UV-vis DRS and XPS analyses revealed a marginal red shift in band-gap and the presence of sp2-hybridized graphitic carbon, and metal-carbon interactions, indicating enhanced light absorption and charge separation through Schottky junctions. Under direct sunlight illumination, Pd-CD/TiO2 thin film exhibited superior hydrogen yield (1167 mu mol g-1 h-1) and maintained stability over 25 h, outperforming Ni-CD/TiO2 (494 mu mol g-1 h-1) and bare TiO2 (166 mu mol g-1 h-1) photocatalyst thin films. Concurrent glycerol oxidation at neutral pH (pH similar to 7) yields glycolaldehyde (41\% selectivity), formic acid, and dihydroxyacetone as value-added products. Enhanced photocurrent density and lower impedance of Pd-CD/TiO2 corroborate improved charge carrier separation and dynamics. The results demonstrate that Pd-CD synergistically improves the photocatalytic performance of the Pd-CD/TiO2 for sustainable hydrogen generation and selective biomass valorization.

}, keywords = {Glycerol oxidation, Graphitic carbon dots, hydrogen production, Photocatalysis, titania}, issn = {1861-4728}, doi = {10.1002/asia.202500757}, author = {Abraham, Athira and Salgaonkar, Kranti N. and Nivedhitha, Thazhath R. and Ekal, Vishal Ashok and Kondhekar, Deepali and Chakraborty, Shubhankar and Gopinath, Chinnakonda S. and Saha, Avishek} } @article {49792, title = {Visible-light-driven photocatalytic glycerol oxidation to value-added and highly selective glyceric/lactic acid}, journal = {ChemiCatChem}, volume = {17}, year = {2025}, month = {SEP}, type = {Article}, abstract = {

Achieving economical and sustainable artificial photosynthesis (APS) in direct sunlight for liquid fuel production with high efficiency remains an important challenge. A major obstacle in the photoelectrochemical (PEC) oxidation of organic compounds is attaining high selectivity with the desired product(s). This study introduces a novel strategy by integrating BiVO4 quantum dots (BVQDs), structurally and electronically, into the nanopores of commercial TiO2 (BVT for BVQDs integrated in pores of TiO2) to improve solar-driven photocatalysis. The band gap of the BVT photoanode decreases to 2.53 eV as compared to pure TiO2 (3.2 eV), which enhances visible light absorption and charge separation. BVT with Pt as a co-catalyst acts as an APS system, which selectively oxidizes glycerol into lactic acid (100\% selectivity at 1 mM glycerol) and glyceric acid (98\% selectivity at 100 mM), while simultaneously generating green hydrogen. Selectivity of the product can be further controlled by anaerobic or aerobic conditions as well as the length of the reaction time. Direct integration of BVQDs into TiO2 mesopores significantly enhances charge separation as well as utilization at redox sites. Current work provides key insights into optimizing photocatalytic conditions for highly selective value-added chemical production, which highlights the sustainability and efficacy of TiO2-based semiconductors with quantum dot integration.

}, keywords = {energy conversion, Energy storage, Photocatalysis, Quantum material, solar energy}, issn = {1867-3880}, doi = {10.1002/cctc.202500641}, author = {Kulkarni-Sambhare, Mukta and Salgaonkar, Kranti N. and Saha, Avishek and Gopinath, Chinnakonda S.} }