@article {44616, title = {Flexible composite mechanical energy harvester from a ferroelectric organoamino phosphonium salt}, journal = {Angewandte Chemie-International Edition}, volume = {57}, year = {2018}, month = {JUL}, pages = {9054-9058}, abstract = {

A new binary organic salt diphenyl diisopropylamino phosphonium hexaflurophosphate (DPDPPF6) was shown to exhibit a good ferroelectric response and employed for mechanical energy harvesting application. The phosphonium salt crystallizes in the monoclinic noncentrosymmetric space group Cc and exhibits an H-bonded 1D chain structure due to N-HF interactions. Ferroelectric measurements on the single crystals of DPDPPF6 gave a well-saturated rectangular hysteresis loop with a remnant (P-r) polarization value of 6Ccm(-2). Further, composite devices based on polydimethylsiloxane (PDMS) films for various weight percentages (3, 5, 7, 10 and 20wt\%) of DPDPPF6 were prepared and examined for power generation by using an impact test setup. A maximum output peak-to-peak voltage (V-PP) of 8.5V and an output peak-to-peak current (I-PP) of 0.5A was obtained for the non-poled composite film with 10wt\% of DPDPPF6. These results show the efficacy of organic ferroelectric substances as potential micropower generators.

}, keywords = {binary phosphonium salts, energy conversion, ferroelectricity, hydrogen bonding, polymer composites}, issn = {1433-7851}, doi = {10.1002/anie.201805479}, author = {Vijayakanth, Thangavel and Srivastava, Anant Kumar and Ram, Farsa and Kulkarni, Priyangi and Shanmuganathan, Kadhiravan and Praveenkumar, Balu and Boomishankar, Ramamoorthy} } @article {46876, title = {Cu-Ni bimetal integrated TiO2 thin film for enhanced solar hydrogen generation}, journal = {Solar RRL}, volume = {4}, year = {2020}, month = {MAY}, pages = {1900557}, type = {Article}, abstract = {

A series of non-noble Cu-Ni bimetallic catalysts is prepared with different molar proportions of metals. Of these bimetallic catalysts, 1 wt\% is subsequently integrated with titania P25. The catalysts are evaluated for solar hydrogen generation under 1 sun condition in both the powder and thin film forms. All the photocatalysts in the thin film exhibit an 8-24 times higher hydrogen yield (HY) compared with the corresponding particulate counterpart. The highest HY (41.7 mmol h(-1) g(-1)) is demonstrated for the photocatalyst Cu-Ni/TiO2 (CNT; 1:1 = Cu:Ni) in the thin film form, which is 24 times higher than that with its powder counterpart (1.75 mmol h(-1) g(-1)) and exceeds the performance of other Cu-Ni/TiO2 compositions. This enhanced activity in the thin film can be ascribed to improved absorption of visible light and an effective separation of photogenerated charge carriers at the interface of Cu-Ni/TiO2 leading to better charge carrier utilization.

}, keywords = {bimetals, energy conversion, Hydrogen, Photocatalysis, solar energy}, issn = {2367-198X}, doi = {10.1002/solr.201900557}, author = {Tudu, Bijoy and Nalajala, Naresh and Saikia, Pranjal and Gopinath, Chinnakonda S.} } @article {46893, title = {Piezoelectric energy harvesting from a ferroelectric hybrid salt [Ph3MeP](4)[Ni(NCS)(6)] embedded in a polymer matrix}, journal = {Angewandte Chemie-International Edition}, volume = {59}, year = {2020}, month = {JUN }, pages = {10368-10373}, type = {Article}, abstract = {

Organic-inorganic hybrid ferroelectrics are an exciting class of molecular materials with promising applications in the area of energy and electronics. The synthesis, ferroelectric and piezoelectric energy harvesting behavior of a 3d metal ion-containing A(4)BX(6) type organic-inorganic hybrid salt [Ph3MeP](4)[Ni(NCS)(6)] (1) is now presented. P-E hysteresis loop studies on 1 show a remnant ferroelectric polarization value of 18.71 mu C cm(-2), at room temperature. Composite thermoplastic polyurethane (TPU) devices with 5, 10, 15 and 20 wt \% compositions of 1 were prepared and employed for piezoelectric energy harvesting studies. A maximum output voltage of 19.29 V and a calculated power density value of 2.51 mW cm(-3) were observed for the 15 wt \% 1-TPU device. The capacitor charging experiments on the 15 wt \% 1-TPU composite device shows an excellent energy storage performance with the highest stored energies and measured charges of 198.8 mu J and 600 mu C, respectively.

}, keywords = {energy conversion, mechanical properties, non-covalent interactions, organic-inorganic hybrid composites, Phosphorus}, issn = {1433-7851}, doi = {10.1002/anie.202001250, Early Access Date = APR 2020}, author = {Vijayakanth, Thangavel and Ram, Farsa and Praveenkumar, Balu and Shanmuganathan, Kadhiravan and Boomishankar, Ramamoorthy} } @article {48122, title = {Co-Ni layered double hydroxide for the electrocatalytic oxidation of organic molecules: an approach to lowering the overall cell voltage for the water splitting process}, journal = {ACS Applied Materials \& Interfaces}, volume = {14}, year = {2022}, month = {APR}, pages = {16222-16232}, type = {Article}, abstract = {

Electrocatalytic oxidation of simple organic molecules oilers a promising strategy to combat the sluggish kinetics of the water oxidation reaction (WOR). The low potential requirement, inhibition of the crossover of gases, and formation of value-added products at the anode are benefits of the electrocatalytic oxidation of organic molecules. Herein, we developed cobalt-nickel-based layered double hydroxide (LDH) as a robust material for the electrocatalytic oxidation of alcohols and urea at the anode, replacing the WOR. A facile synthesis protocol to form LDHs with different ratios of Co and Ni is adapted. It demonstrates that the reactants could be efficiently oxidized to concomitant chemical products at the anode. The half-cell study shows an onset potential of 1.30 V for benzyl alcohol oxidation reaction (BAOR), 1.36 V for glycerol oxidation reaction (GOR), 1.33 V for ethanol oxidation reaction (EOR), and 1.32 V for urea oxidation reaction (UOR) compared with 1.53 V for WOR. Notably, the hybrid electrolyzer in a full-cell configuration significantly reduces the overall cell voltage at a 20 mA cm(-2) current density by similar to 15\% while coupling with the BAOR, EOR, and GOR and similar to 12\% with the UOR as the anodic half-cell reaction. Furthermore, the efficiency of hydrogen generation remains unhampered with the types of oxidation reactions (alcohols and urea) occurring at the anode. This work demonstrates the prospects of lowering the overall cell voltage in the case of a water electrolyzer by integrating the hydrogen evolution reaction with suitable organic molecule oxidation.

}, keywords = {electrocatalytic oxidation, energy conversion, imidazole mediated, Layered compounds, water splitting}, issn = {1944-8244}, doi = {10.1021/acsami.2c00982}, author = {Shilpa, Nagaraju and Pandikassala, Ajmal and Krishnaraj, Perayil and Walko, Priyanka S. and Devi, R. Nandini and Kurungot, Sreekumar} } @article {49140, title = { Ferroelectric aminophosphonium cyanoferrate with a large electrostrictive coefficient as a piezoelectric nanogenerator}, journal = {Angewandte Chemie-International Edition}, volume = {62}, year = {2023}, month = {JAN }, type = {Article}, abstract = {

Hybrid materials possessing piezo- and ferroelectric properties emerge as excellent alternatives to conventional piezoceramics due to their merits of facile synthesis, lightweight nature, ease of fabrication and mechanical flexibility. Inspired by the structural stability of aminophosphonium compounds, here we report the first A(3)BX(6) type cyanometallate [Ph-2((PrNH)-Pr-i)(2)P](3)[Fe(CN)(6)] (1), which shows a ferroelectric saturation polarization (P-s) of 3.71 mu C cm(-2). Compound 1 exhibits a high electrostrictive coefficient (Q(33)) of 0.73 m(4) C-2, far exceeding those of piezoceramics (0.034-0.096 m(4) C-2). Piezoresponse force microscopy (PFM) analysis demonstrates the polarization switching and domain structure of 1 further confirming its ferroelectric nature. Furthermore, thermoplastic polyurethane (TPU) polymer composite films of 1 were prepared and employed as piezoelectric nanogenerators. Notably, the 15 wt \% 1-TPU device gave a maximum output voltage of 13.57 V and a power density of 6.03 mu W cm(-2).

}, keywords = {Cyanometallates, energy conversion, H-bonding, hybrid composites, Phosphorus}, issn = {1433-7851}, doi = {10.1002/anie.202214984}, author = {Vijayakanth, Thangavel and Sahoo, Supriya and Kothavade, Premkumar and Sharma, Vijay Bhan and Kabra, Dinesh and Zareba, Jan K. K. and Shanmuganathan, Kadhiravan and Boomishankar, Ramamoorthy} } @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 {49185, title = {Aqueous glycerol to glyceric acid and green hydrogen by visible-light-driven photocatalysis with Ni/Co(PO4)2-TiO2: parallel utilization of holes and electrons}, journal = {ACS Sustainable Chemistry \& Engineering}, volume = {12}, year = {2024}, month = {SEP}, pages = {14841-14853}, type = {Article}, abstract = {

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.

}, keywords = {biomass component, earth-abundantmaterial, energy conversion, organicvalorisation, water splitting}, issn = {2168-0485}, doi = {10.1021/acssuschemeng.4c05853}, author = {Nivedhitha, Thazhath R. and Bajpai, Himanshu and Oommen, Jiffin Varghese and Abraham, Athira and Chauhan, Inderjeet and Gopinath, Chinnakonda S.} } @article {49706, title = {Mesoporous Fe2O3-TiO2 integrated with plasmonic Ag nanoparticles for enhanced solar H2 production}, journal = {Chemistry-An Asian Journal}, volume = {20}, year = {2025}, month = {MAY}, type = {Article}, abstract = {

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.

}, keywords = {energy conversion, green hydrogen, Photocatalysis, Solar harvesting, water splitting}, issn = {1861-4728}, doi = {10.1002/asia.202401664}, author = {Mani, Sunesh S. and Rajendran, Sivaraj and Saju, Simi and Babu, Bindhya M. and Mathew, Thomas and Gopinath, Chinnakonda S.} }