02674nas a2200265   4500008004100000022001400041245011200055210006900167260007700236300001200313490000600325520169700331653002802028653001302056653002502069653001902094653002002113100003302133700002502166700001602191700001502207700002702222700003002249856012902279       2014                        eng d  a1867-388000aDisordered mesoporous TiO2-xNx+Nano-Au: an electronically integrated nanocomposite for solar H-2 generation0 aDisordered mesoporous TiO2xNxNanoAu an electronically integrated  aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcFEB  a522-5300 v63 a<p>We report on H-2 generation by photocatalysis driven by simulated white light by electronically integrated Au nanoparticles with multifunctional, disordered mesoporous TiO2-xNx (Au-NT) nanocomposites. Solar H-2 generation (1.5 mmolh(-1)g(-1)) from aqueous methanol has been demonstrated with Au-NT nanocomposites. The water splitting activity of Au-NT is attributed to the 21.1 ps lifetime of charge carriers observed from fluorescence lifetime measurements, which indicates a high electron-injection efficiency from nano-Au to the conduction band of TiO2, and hence charge separation as well as utilization. This is directly supported by the observation of a high photoluminescence emission intensity with Au-NT that highlights the energy transfer from nano-Au to TiO2. The p-n heterojunction observed between the Au (001) and TiO2 (101) facets helps to-wards the higher charge separation and their utilization. A low mesochannel depth (&lt; 10 nm) associated with disordered mesoporous TiO2-xNx helps the charge carriers to move towards the surface for redox reactions and hence charge utilization. Visible-light absorption, as a result of the surface plasmon resonance of nano-Au, is observed in a broad range between 500 and 750 nm, which helps in harvesting visible-light photons. Finally, electronically integrated nano-Au with TiO2-xNx in Au-NT is evident from Raman and X-ray photoelectron spectroscopy measurements. All of these factors help to achieve a high rate of H-2 production. It is likely that a higher rate of H-2 production than that reported here is feasible by strategically locating Au clusters in porous TiO2 to generate hot spots through electronic integration.</p>10aheterogeneous catalysis10aHydrogen10amesoporous materials10aphotochemistry10awater splitting1 aSivaranjani, Kumarsrinivasan1 aRajaambal, Sivaraman1 aDas, Tanmay1 aRoy, Kanak1 aBhattacharyya, Somnath1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/disordered-mesoporous-tio2-xnxnano-au-electronically-integrated-nanocomposite-solar-h-2-002506nas a2200253   4500008004100000022001400041245006900055210006800124260010200192300001000294490000800304520163300312653001301945653001701958653001901975653001601994653001802010653001802028653002002046100002502066700003302091700003002124856009802154       2015                        eng d  a0974-362600aRecent developments in solar H-2 generation from water splitting0 aRecent developments in solar H2 generation from water splitting  aC V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIAbINDIAN ACAD SCIENCEScJAN  a33-470 v1273 a<p>Hydrogen production from water and sunlight through photocatalysis could become one of the channels, in the not-so-distant future, to meet a part of ever growing energy demands. However, accomplishing solar water splitting through semiconductor particulate photocatalysis seems to be the `Holy Grail' problem of science. In the present mini-review, some of the critical strategies of semiconductor photocatalysis are focused with the aim of enumerating underlying critical factors such as visible light harvesting, charge carrier separation, conduction and their utilization that determine the quantum efficiency. We attempted to bring out the essential requirements expected in a material for facile water splitting by explaining important and new designs contributed in the last decade. The newly emerged designs in semiconductor architecture employing nanoscience towards meeting the critical factors of facile photocatalysis are elucidated. The importance of band gap engineering is emphasized to utilize potential wide band gap semiconductors. Assistance of metal nanostructures and quantum dots to semiconductors attains vital importance as they are exuberant visible light harvesters and charge carrier amplifiers. Benevolent use of quantum dots in solar water splitting and photoelectrochemical water splitting provides scope to revolutionize the quantum efficiency by its multiple exciton generation features. A list of drawbacks and issues that hamper the much needed breakthrough in photocatalysis of water splitting is provided to invite attention to address them and move towards sustainable water splitting.</p>10aHydrogen10ananomaterial10aPhotocatalysis10aquantum dot10aSemiconductor10avisible light10awater splitting1 aRajaambal, Sivaraman1 aSivaranjani, Kumarsrinivasan1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/recent-developments-solar-h-2-generation-water-splitting-002085nas a2200241   4500008004100000022001400041245011900055210006900174260000800243300001200251490000600263520126900269653002001538653001201558653001801570653001201588653002001600100002601620700001701646700002001663700003001683856013001713       2018                        eng d  a2194-428800aMarginally hydrogenated triphasic titania nanotubes for effective visible-light photocatalytic hydrogen generation0 aMarginally hydrogenated triphasic titania nanotubes for effectiv  cFEB  a280-2880 v63 a<p>We report the first demonstration of hydrogen-annealed triphase TiO nanotubes (anatase-rutile-brookite) (T-ARB) as a visible-light-active photocatalyst for water splitting with high quantum efficiency. As-synthesized T-ARB was annealed under hydrogen atmosphere at 250 and 4508 degrees C for 2 h. We found that the tubular structures were retained in the hydrogenated TiO2 samples. It was observed that the concentrations of Ti3+ and the oxygen vacancies and their distribution significantly increased with respect to the hydrogen annealing temperature. Such changes in defects were found to be critical in enhancing the photocatalytic activity of the hydrogen-annealed triphase TiO2 nanotubes. The triphase TiO2 nanotubes hydrogen annealed at 450 degrees C were 16 times more efficient than pristine TiO2. Such an increase in the photocatalytic activity was explained by a triphase band diagram with defect states below the conduction band of each phase, which facilitated visible-light activity and easy transfer of charge carriers from one phase to another. Our study showed that the well-designed multiphase construction with oxygen vacancies enhanced the photocatalytic activity tremendously owing to the presence of a higher number of phase junctions.</p>10acharge transfer10aDefects10aHydrogenation10atitania10awater splitting1 aPreethi, Laguduva, K.1 aMathews, Tom1 aWalczak, Lukasz1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/marginally-hydrogenated-triphasic-titania-nanotubes-effective-visible-light-photocatalytic02416nas a2200217   4500008004100000022001400041245009900055210006900154260000800223300001200231490000700243520166800250653002701918653001901945653002101964653001901985653002002004100002202024700003002046856012202076       2018                        eng d  a0360-319900aPt - g-C3N4 - (Au/TiO2): electronically integrated nanocomposite for solar hydrogen generation0 aPt gC3N4 AuTiO2 electronically integrated nanocomposite for sola  cJAN  a601-6130 v433 a<p>A potential nanocomposite photocatalyst was designed by integrating Pt nanoclusters (co catalyst and electron sink) with graphitic carbon nitride (g-C3N4 (gcn)) (charge diffusion) and 0.5 wt % Au containing Au-TiO2 (AuT) (plasmonic on semiconductor) for solar water splitting (SWS). Variety of Pt-gcn-AuTiO2 compositions has been evaluated for SWS under one sun conditions. Complexity of the photocatalyst was increased systematically from Au-TiO2, gcn-TiO2 to Pt-gcn-Au-TiO2 to explore the influence of different combinations. Electronic integration of charge separation/diffusion component (gcn) with light absorbing sensitizer components (Au and gcn), and co-catalyst (Pt) seems to be the critical factor to improve hydrogen yield (HY) or overall efficiency. Although addition of gcn increase the HY of composites, there is no SWS activity observed on bare TiO2 or gcn. Au or Pt on gcn enhances the charge separation effectively and interface between Au and/or Pt with gcn works as the Schottky barrier. A monodispersion of Au over TiO2 and Pt nanoclusters over gcn/AuTiO2 composite lead to the maximum solar hydrogen yield (1.52 mmol/h g) with an apparent quantum yield (AQY) of 7.5%. Photoelectron and photoluminescence spectral studies confirm the electron transfer from Au to gcn, and Au and/or gcn to titania. A thorough physico-chemical investigation of various composites underscores the electronic integration aspects of the nanocomposite towards storage of electrons in the Pt co-catalyst and hence an effective charge separation and an increase in AQY. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.</p>10aElectronic integration10aPhotocatalysis10aSchottky barrier10aSolar hydrogen10awater splitting1 aDevaraji, Perumal1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/pt-g-c3n4-autio2-electronically-integrated-nanocomposite-solar-hydrogen-generation02821nas a2200253   4500008004100000022001400041245010600055210006900161260000800230300001600238490000700254520197500261653001202236653001902248653003002267653000902297653002002306100001602326700002102342700002202363700002002385700003002405856013202435       2019                        eng d  a1944-824400aElectronic integration and thin film aspects of Au-Pd/rGO/TiO2 for improved solar hydrogen generation0 aElectronic integration and thin film aspects of AuPdrGOTiO2 for   cSEP  a32869-328780 v113 a<p>In the present work, we have synthesized noble bimetallic nanoparticles (Au-Pd NPs) on a carbon-based support and integrated with titania to obtain Au-Pd/C/TiO2 and Au-Pd/rGO/TiO2 nanocomposites using an ecofriendly hydrothermal method. Here, a 1:1 (w/w) Au-Pd bimetallic composition was dispersed on (a) high-surface-area (3000 m(2) g(-1)) activated carbon (Au-Pd/C), prepared from a locally available plant source (in Assam, India), and (b) reduced graphene oxide (rGO) (Au-Pd/rGO); subsequently, they were integrated with TiO2. The shift observed in Raman spectroscopy demonstrates the electronic integration of the bimetal with titania. The photocatalytic activity of the above materials for the hydrogen evolution reaction was studied under 1 sun conditions using methanol as a sacrificial agent in a powder form. The photocatalysts were also employed to prepare a thin film by the drop-casting method. Au-Pd/rGO/TiO2 exhibits 43 times higher hydrogen (H-2) yield in the thin film form (21.50 mmol h(-1) g(-1)) compared to the powder form (0.50 mmol h(-1) g(-1)). On the other hand, Au-Pd/C/TiO2 shows 13 times higher hydrogen (H-2) yield in the thin film form (6.42 mmol h(-1) g(-1)) compared to the powder form (0.48 mmol h(-1) g(-1)). While powder forms of both catalysts show comparable activity, the Au-Pd/rGO/TiO2 thin film shows 3.4 times higher activity than that of Au-Pd/C/TiO2. This can be ascribed to (a) an effective separation of photogenerated electron-hole pairs at the interface of Au-Pd/rGO/TiO2 and (b) the better field effect due to plasmon resonance of the bimetal in the thin film form. The catalytic influence of the carbon-based support is highly pronounced due to synergistic binding interaction of bimetallic nanoparticles. Further, a large amount of hydrogen evolution in the film form with both catalysts (Au-Pd/C/TiO2 and Au-Pd/rGO/TiO2) reiterates that charge utilization should be better compared to that in powder catalysts.</p>
10abimetal10aPhotocatalysis10asurface plasmon resonance10aTiO210awater splitting1 aTudu, Bijoy1 aNalajala, Naresh1 aReddy, Kasala, P.1 aSaikia, Pranjal1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/electronic-integration-and-thin-film-aspects-au-pdrgotio2-improved-solar-hydrogen-generation02522nas a2200265   4500008004100000022001400041245010300055210006900158260000900227300001600236490000600252520166000258653001501918653001301933653001601946653001701962653000901979653002001988100001602008700002102024700002902045700002002074700003002094856013202124       2021                        eng d  a2168-048500aRationally designed, efficient, and earth-abundant Ni-Fe cocatalysts for solar hydrogen generation0 aRationally designed efficient and earthabundant NiFe cocatalysts  cOCT   a13915-139250 v93 aDeveloping highly efficient and affordable catalysts for solar hydrogen (H-2) generation is crucial, and employing a cocatalyst from earth-abundant elements has a critical role to play. In this context, different compositions of earth-abundant Ni-Fe alloy (1:1, 1:3, and 3:1) have been prepared by hydrothermal method; subsequently, 1 wt % of these Ni-Fe cocatalysts were integrated with TiO2-P25 and thoroughly characterized. The resultant catalysts have been evaluated for solar H-2 production, in powder and thin film forms, under one sun condition and in direct sunlight. Interestingly, all the catalysts in the thin film form exhibit superior hydrogen yield (HY), up to 27 times higher activity than its powder counterpart. Among the photocatalysts, Ni-Fe/TiO2 (3:1 = Ni/Fe; NFT31) composition exhibits the best HY in thin film (8.27 mmol.h(-1).g(-1)) and exceeds all other compositions of catalyst. It is also to be reported that HY measured for the powder form with 1 mg shows 3-17 times higher activity than that measured with 25 mg. This is mainly attributed to effective solar light absorption with a smaller amount of photocatalyst either spread over large area in a thin film form or well-dispersed in suspension forms. Furthermore, the enhanced activity obtained with Ni-Fe/TiO2 photocatalysts is also ascribed to strong electronic integration of Ni-Fe cocatalyst with TiO2 and higher performance obtained with a thin film is attributed to increased charge carrier generation and subsequent charge separation and effective utilization. A decrease in work function of TiO2 by 0.6 eV was observed after its integration with cocatalyst in NFT31.10aCocatalyst10aHydrogen10aNi-Fe alloy10asolar energy10aTiO210awater splitting1 aTudu, Bijoy1 aNalajala, Naresh1 aReddy, Kasala, Prabhakar1 aSaikia, Pranjal1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/rationally-designed-efficient-and-earth-abundant-ni-fe-cocatalysts-solar-hydrogen-generation02229nas a2200241   4500008004100000022001400041245010800055210006900163260000800232300000700240490000800247520142000255653001001675653002701685653001901712653001401731653002001745100001801765700002601783700002401809700003001833856012401863       2022                        eng d  a0974-362600aFacile, sustainable and unassisted plain water oxidation on Au/Ce0.9Ti0.1O2 nanorods in direct sunlight0 aFacile sustainable and unassisted plain water oxidation on AuCe0  cJUN  a610 v1343 a<p>
	Impressive rate of solar water oxidation to molecular oxygen (O-2) has been demonstrated on nanorods (NRs) of Ce0.9Ti0.1O2 (CT-NR) and Au-deposited CT-NR (Au-CT-NR) photocatalysts with a sacrificial agent (Fe3+) and in plain water in one sun condition, direct sunlight and with lambda &gt;= 455 nm. Probably the highest 0 2 yield of 11 mmol/h.g was observed with Au-CT-NR thin film in plain water in direct sunlight, with no sacrificial agent or applied potential. Photoelectrochemical measurements demonstrate a marked reduction in oxidation onset potential of Au-CT-NR by 150 mV with stable photocurrent (0.75 mA/cm(2)), compared to CT-NR (0.23 mA/cm(2)), indicating the operative of plasmon-induced resonant energy transfer (PIRET) process. Effective electron quenching by nanogold and hence low recombination in the depletion region is a critical step for the observation of a high rate of oxygen evolution. In addition to this, a predominant change in the nature of the valence band from O-2p dominated on CeO2 to Ce-4f dominated with CT-NR (due to Ti4+ introduction in CeO2), the efficient light absorption of photocatalysts in thin-film form, functional and effective PIRET process, and facile E-F alignment, enhances the oxygen evolution with Au-CT-NR in direct sunlight and make it highly sustainable. A possible mechanism of water oxidation is proposed from the observed experimental findings.</p>
10aceria10aElectronic integration10aPhotocatalysis10athin film10awater splitting1 aDubey, Anjani1 aMishra, Abhaya, Kumar1 aNegi, Sanjay, Singh1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/facile-sustainable-and-unassisted-plain-water-oxidation-auce09ti01o2-nanorods-direct02809nas a2200265   4500008004100000022001400041245016300055210006900218260000800287300001600295490000700311520183300318653002202151653002702173653002202200653002402222653002002246100002902266700002102295700002902316700002002345700002302365700003002388856012502418       2024                        eng d  a2168-048500aAqueous glycerol to glyceric acid and green hydrogen by visible-light-driven photocatalysis with Ni/Co(PO4)2-TiO2: parallel utilization of holes and electrons0 aAqueous glycerol to glyceric acid and green hydrogen by visiblel  cSEP  a14841-148530 v123 a<p>
	Replacing the kinetically sluggish oxygen evolution reaction (OER) with the oxidation of an abundantly available organic molecule to value-added product(s) (VAPs) at low voltage along with the hydrogen evolution reaction (HER) is a big challenge in water splitting, either by electrolysis or sunlight-driven photocatalysis. Glycerol oxidation to a VAP is kinetically fast, compared to an OER, and offers hope to enhance sunlight-driven water splitting to hydrogen by the concurrent utilization of holes and electrons. Mixed bimetal phosphates of Co and Ni (CoxNiy(PO4)(2) (CoNiP)) with different Co:Ni ratios (10:0, 7:3, 5:5, 3:7, and 0:10) were integrated with TiO2 to generate final photocatalyst composites (x wt % CoNiP with TiO2) and employed for concurrent photocatalytic HER and glycerol oxidation. Irrespective of the weight ratios of CoNiP and TiO2, any TiO2-CoNiP composite showed better photocatalytic activity for the HER and glycerol oxidation compared to virgin TiO2. The highest HER as well as selectively generated glyceric acid yield was observed to be 54 and 67 mmol/g, respectively, after 25 h of reaction under 1 sun conditions with TiO2-CoNiP-5:5. An increase in catalytic activity can be attributed to the formation of p-n heterojunctions of the constituent component along with uniform distribution of CoNiP to effectively utilize the charge carriers for redox reactions. Highly selective oxidation of glycerol to glyceric acid (85%), along with other minor products, is also demonstrated, which offers further scope to use solar light to generate VAPs in a sustainable manner. A simple comparison of H-2 yield and all oxidized products together indicates the better utilization of holes for the latter, and hence, there is scope to increase HER and possibly the whole photocatalytic activity.</p>
10abiomass component10aearth-abundantmaterial10aenergy conversion10aorganicvalorisation10awater splitting1 aNivedhitha, Thazhath, R.1 aBajpai, Himanshu1 aOommen, Jiffin, Varghese1 aAbraham, Athira1 aChauhan, Inderjeet1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/aqueous-glycerol-glyceric-acid-and-green-hydrogen-visible-light-driven-photocatalysis02217nas a2200253   4500008004100000022001400041245010200055210006900157260000800226490000700234520136300241653002201604653001901626653001901645653002101664653002001685100002101705700002301726700001501749700002201764700001901786700003001805856012801835       2025                        eng d  a1861-472800aMesoporous Fe2O3-TiO2 integrated with plasmonic Ag nanoparticles for enhanced solar H2 production0 aMesoporous Fe2O3TiO2 integrated with plasmonic Ag nanoparticles   cMAY0 v203 a<p>
	Present work describes a sol-gel assisted one-pot synthesis of mesoporous Fe2O3-TiO2 nanocomposites (TiFe) with different Ti : Fe ratios, and fabrication of Ag-integrated with TiFe nanocomposites (TiFeAg) by a chemical reduction method and demonstrated for high solar H2 generation activity in direct sunlight. Enhanced solar H2 production is attributed to the light absorption from entire UV+Visible region of solar spectrum combined with Schottky (Ag-semiconductor) and heterojunctions (TiO2-Fe2O3), as evidenced from HRTEM and various characterization studies. TiFeAg-2 thin film (1 wt % Ag-loaded TiFe-4) displayed the highest activity with a solar H2 yield of 7.64 mmol h-1g-1, which is 48 times higher than that of bare TiO2 and 5 times higher in thin film form compared to its powder counterpart. Schottky and heterojunctions formed at the interface efficiently separate the charge carriers and increase the hydrogen production activity. The highest H2 production activity of TiFeAg-2 is partly attributed to the heterogeneous distribution of Fe3+ and metallic Ag-species with relatively high Ag/Ti surface atomic ratio. A plausible photocatalytic reaction mechanism on TiFeAg nanocomposite may involve the direct electron transfer from both Fe2O3 and TiO2 to Ag nanoparticles which are subsequently utilized for the reduction of H+ to H2.</p>
10aenergy conversion10agreen hydrogen10aPhotocatalysis10aSolar harvesting10awater splitting1 aMani, Sunesh, S.1 aRajendran, Sivaraj1 aSaju, Simi1 aBabu, Bindhya, M.1 aMathew, Thomas1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/mesoporous-fe2o3-tio2-integrated-plasmonic-ag-nanoparticles-enhanced-solar-h2-production