Pavuluri Srinivasu

Highly efficient nanoporous graphitic carbon with tunable textural properties for dye-sensitized solar cells

Nanoporous graphitic carbon (NGC) is synthesized by direct carbonization of iron phthalocyanine (Fe-PC) and 3D mesoporous silica (KIT-6) mixture for the first time, which exhibits tunable surface area and pore volume, as well as superior energy conversion efficiency for dye-sensitized solar cells compared to activated carbon (AC) and large porous carbon (LPC).

Metal-Free Counter Electrode for Efficient Dye-Sensitized Solar Cells through High Surface Area and Large Porous Carbon

Highly efficient, large mesoporous carbon is fabricated as a metal-free counter electrode for dye-sensitized solar cells. The mesoporous carbon shows very high energy conversion efficiency of 7.1% compared with activated carbon. The mesoporous carbon is prepared and characterized by nitrogen adsorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The nitrogen adsorption data reveals that the material possesses BET specific surface area ca.1300 m2/g and pore diameter 4.4 nm. Hexagonal rod-like morphology and ordered pore structure of mesoporous carbon are confirmed by electron microscopy data. The better performance of this carbon material is greatly benefited from its ordered interconnected mesoporous structure and high surface area.

Metal organic framework MIL-101(Cr) for dehydration reactions

Abstract.Porous chromium terephthalate MIL-101 (Cr-MIL-101) has been prepared by direct method under hydrothermal conditions and characterized using X-ray diffraction, N2 sorption, TGA and FT-IR. The nitrogen adsorption–desorption isotherm shows that the Cr-MIL-101 possesses BET specific surface area of 2563 m2/g. Catalytic performance of Cr-MIL-101 in the dehydration of 1,4-butanediol and 1-phenyl ethanol is assessed under vapour phase conditions in the temperature range of 513–533 K and time on stream (TOS) at 513 K. Cr-MIL-101 demonstrates superior catalytic activity with conversion of 95% of 1-phenyl ethanol. Moreover, high surface area and nanocages with coordinated unsaturated sites of Cr-MIL-101 have allowed us to attain higher dehydrated products selectivity than Cr-supported activated carbon (Cr/AC), amberlyst-15 and HZSM-5 catalysts.n Graphical abstract.Dehydration of 1-pheny lethanol and 1,4-butanediol has been carried out over Cr-MIL-101 catalyst in vapour phase in the temperature range of 498–533K at atmospheric pressure shows highest conversion and selectivity of styrene and tetrahydrofuran respectively, due to availability of co-ordinated unsatured sites and uniform distribution of pores of the catalyst.

Ordered Hexagonal Mesoporous Aluminosilicates and their Application in Ligand‐Free Synthesis of Secondary Amines

A new facile synthesis of ordered mesoporous aluminosilicates has been developed and applied for the efficient catalytic synthesis of N‐benzyl secondary amines under ligand and base‐free conditions. The MAS(38) catalyst with a well‐ordered mesoporous structure and strong acidic sites was used for acid‐catalyzed organic transformations and its operational simplicity and ease of its isolation procedure make it an attractive alternative to current methodologies.

Solar Energy Conversion by Dye-Sensitized Photovoltaic Cells Using High Surface Area Mesoporous Carbon Counter Electrode

Development of new counter electrode materials is vital for commercialization of efficient dye-sensitized solar cells (DSCs) process. Research on DSCs has been focused mainly on using platinum as counter electrode, which makes them expensive. In this paper, we report DSCs fabricated with high surface area mesoporous carbon thin film with uniform spherical particles as counter electrode. An overall light-to-electricity efficiency as high as 7.6% has been achieved under illumination of air mass (AM) 1.5 sunlight (100u2009mW/cm2). In comparison with activated carbon, high surface area mesoporous carbon shows superior performance. Our results show that mesoporous carbon with high specific surface area and uniform pore size distribution proved to be better efficient electrode material for DSCs.

Novel Approach for the Synthesis of Nanocrystalline Anatase Titania and Their Photovoltaic Application

High surface area titania with crystalline anatase walls has been synthesized using ordered large mesoporous carbon as a template. The pore structure of mesoporous carbon is infiltrated with titanium tetraisopropoxide solution at room temperature and the mixture is subjected to heat treatment at 550oC in presence of air to complete removal of the template. The prepared crystalline anatase frameworks are characterized by XRD, N2 adsorption and HR-TEM. The nitrogen adsorption-desorption analysis of the prepared anatase titania particles exhibits BET specific surface area of 28u2009m2/g. The dye-sensitized solar cells performance of this anatase titania material has been tested and energy conversion efficiency of 3.0% is achieved under AM 1.5 sunlight. This work reports a new approach for fabrication of nanocrystalline anatase titania by simple hard templating technique for the first time and their applications for dye-sensitized solar cell.

A New Heteroleptic Biquinoline Ruthenium(II) Sensitizer for Near-IR Sensitization of Nanocrystalline TiO2

Ruthenium(II) complex containing cis-[Ru(H2dcbiq)(L)(NCS)2], where H2dcbiq = 4,4′-dicarboxy-2,2′-biquinoline and L = 4,4′-di-tert-butyl-2-2′-dipyridyl coded as SPS-02, was synthesized and fully characterized. This complex showed appreciably broad absorption range. The new complex was used as photosensitizer in nanocrystalline TiO2 dye-sensitized solar cell application. cis-[Ru(H2dcbiq)(L)(NCS)2] (SPS-02) achieved efficient sensitization of nanocrystalline TiO2 over the whole visible range, extending into the near-IR region (ca. 1000u2009nm) with superior short-circuit photocurrent density ( = 9.13u2009mAu2009cm−2) and conversion efficiency (η = 2.09%) compared with complex cis-[Ru(H2dcbiq)2(NCS)2] (1) under an irradiation of full sunlight (100u2009mWu2009cm−2).

Dye-Sensitized Solar Cells Based on High Surface Area Nanocrystalline Zinc Oxide Spheres

High surface area nanocrystalline zinc oxide material is fabricated using mesoporous nanostructured carbon as a sacrificial template through combustion process. The resulting material is characterized by XRD, N2 adsorption, HR-SEM, and HR-TEM. The nitrogen adsorption measurement indicates that the materials possess BET specific surface area ca. 30u2009m2/g. Electron microscopy images prove that the zinc oxide spheres possess particle size in the range of 0.12u2009μm–0.17u2009μm. The nanocrystalline zinc oxide spheres show 1.0% of energy conversion efficiency for dye-sensitized solar cells.