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Recently, layered two-dimensional (2D) semiconductor materials composed of group 15 elements (pnictogens) are demonstrated as efficient photocatalysts in various applications. However, only little attention is given to the investigation of their catalytic properties, and even there is no example of the photocatalytic application of bismuthene so far. Here we report for the first time on the use of 2D bismuthene as a photocatalyst in a liquidphase organic transformation. 2D bismuthene is proven to be an efficient photocatalyst that can be operated under various reaction conditions including indoor light illumination, darkness, outdoors and low temperature for the photoredox C-H arylation of (hetero)arenes with high product yields. The presented bismuthene catalyzed photoredox C-H arylation protocol works efficiently on a broad substrate scope of (hetero)arenes with aryl diazonium salts bearing electron-withdrawing and electron-donating groups. Moreover, a density functional theory (DFT) study reveals mechanistic details that lie behind the catalytic activity of bismuthene.

We report herein a facile synthesis of a ternary nanocomposite of strontium oxide modified mesoporous graphitic carbon nitride supported titanium dioxide (SrO-mpg-CN/TiO2) as an efficient heterojunction photocatalyst for the degradation of tetracycline (TC) in water. The morphology, optical and textural properties of as-prepared nanocomposites are systematically investigated by various advanced analytical techniques, and the structure-photocatalytic efficiency was related by proposing a plausible mechanism. The photocatalytic performance of SrO-mpg-CN/TiO2 nanocomposites was evaluated in the TC degradation in water by studying several reaction parameters including the catalyst dosage, initial TC concentration, pH and irradiation time. The photocatalytic experiments exhibited that the activity of SrO-mpg-CN/ TiO2 nanocomposites for TC degradation was higher than binary SrO-mpg-CN nanocomposites and pristine TiO2. The enhanced photocatalytic activity of SrO-mpg-CN/TiO2 nanocomposites is attributed to the moderator role of SrO for electron transportation in the photocatalysis mechanism, which ensures a high charge mobility, suppresses electron/hole recombination, and improves the redox capacity under UVA irradiation. The detailed optimization studies revealed that the highest TC degradation efficiency of 91.73% was obtained by using 0.1 g/L catalyst dosage and 10 mg/L TC concentration at natural pH of 5.06 for 180 min reaction time under UVA irradiation. Moreover, the scavenging experiments showed that OH center dot(ads) and O-2 radicals are the dominant species for the TC degradation in water. Moreover, SrOmpg-CN/TiO2 nanocomposites were reusable up to the five successive runs without a significant drop in their initial activity. (C) 2021 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

In the drive toward the development of efficient and stable inorganic semiconductor materials with broadband solar absorption ability to induce various photochemical processes is a highly attractive research field. In this study, two-dimensional (2D) few-layer black phosphorus (BP) exfoliated in a solvent is utilized as photocatalyst to initiate the polymerization of various monomers under visible and near-IR (NIR) light irradiation. Upon the light exposure, few-layer BP generates excited electrons and holes, which undergo electron transfer reactions with the onium salts to form free radicals capable of initiating free radical polymerization. Among the onium salts tested, aryldiazonium salt was found to be the most efficient in the photopolymerization process owing to its favorable reduction potential with the conduction edge potential of BP. The presented strategy also provides the possibility for the in situ preparation of BP-polymer composite materials.

The monodisperse Au (similar to 5 nm) and Ag (similar to 3 nm) nanoparticles used in this study were obtained using surfactant-assistant solvothermal methods and characterized by XRD TEM and SEM. Then, these nanoparticles were embedded into the P3HT:PCBM photoactive layer at different ratios and the effects of the nanoparticles on the performance of the organic solar cells have been studied by varying the loading percent of the NPs in the range of 0.5-2 wt%. The best solar cell composition was determined to be 1 wt% for Au NPs and 0.5 wt% for Ag NPs. Optical absorption spectrum of P3HT:PCBM, P3HT:PCBM:AuNPs and P3HT:PCBM:AgNPs active layers were obtained using UV-visible spectroscopy. The J-V plots of ITO/PEDOT:PSS/P3HT:PCBM/LiF/Al solar cells having 1.10(-6) m(2) OSC area and with different Au NPs and Ag NPs loading ratios in the P3HT:PCBM were obtained under air mass (AM) 1.5G illumination. Open circuit voltage, short-circuit current density, fill factor, and power conversion efficiency of the OSC were calculated. The highest PCE values were obtained as 3.35% for Au NPs and as 3.50% for Ag NPs doped devices. This increase in PCEs was explained by a plasmonic effect that stems from the metallic NPs.

Herein, for the first time, we introduce the morpholine-borane complex (MB) as a new, efficient, cost-effective and commercially available chemical hydrogen storage material for mobile applications. In this regard, hydrogen production from the hydrolysis of MB catalyzed by in situ generated water-soluble polymer stabilized Ag(0) and Pd(0) nanoparticles (NPs) is reported for the first time. In situ generated PSMA-stabilized Ag(0) and Pd(0) NPs showed remarkable activity in hydrogen production from the hydrolysis of MB at room temperature, providing initial TOFs of 16.1 min(-1) and 37.3 min(-1), respectively. A set of kinetic studies on the catalytic hydrolysis of MB were conducted by changing the catalyst/substrate amount and temperature, and the rate law expression and activation parameters were produced by collecting the kinetic data. The apparent activation energies for the in situ generated Ag(0) and Pd(0) NPs catalyzed MB hydrolysis were calculated to be 71.4 and 32.5 kJ mol(-1), respectively. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

A new and straightforward approach for the synthesis of ultrasmall and monodisperse Pt nanoparticles (NPs) and their controlled assembly on graphene based supports including reduced graphene oxide (rGO), commercial carbon black (VC) and rGO-VC hybrid were reported. These supported NPs were utilized as the electrocatalysts for polymer electrolyte membrane fuel cells (PEMFC). Surfactant-assisted reduction of platinum(II) acetylacetonate in hot organic solution yielded 1.2 nm Pt NPs. These ultrasmall Pt NPs were decorated on rGO, VC and the rGO-VC hybrid by using a simple liquid-phase self-assembly method. In the previous studies on Pt/rGO-VC hybrids, on one hand, Pt NPs were synthesized in situ on support, on the other hand, VC was added to synthesized Pt/rGO, and their fuel cell performance have been rarely shown. In our study, rGO and VC were directly mixed and prepared Pt NPs were assembled on rGO-VC hybrid support. Pt/rGO-VC hybrid electrocatalyst possessed substantially better electrocatalytic activity owing to better utilization of Pt compared to Pt/rGO and Pt/VC. Membrane electrode assemblies based on resultant catalysts were characterized in-situ in PEMFC. A superior PEMFC performance of 857 mW cm(-2) (maximumpower density) was achieved with the hybrid catalyst as compared to Pt NPs supported on rGO or VC. (C) 2018 Elsevier Ltd. All rights reserved.

A perovskite type of strontium titanate (SrTiO3) nanocubes (NCs) were synthesized by using a hydrothermal process and the thin films of these NCs were deposited on an n-type silicon wafer by spin coating technique. As-synthesized SrTiO3 NCs were characterized by transmission electron microscope, scanning electron microscope, energy dispersive x-ray, x-ray diffraction and Raman spectroscopy. After evaporation of 12 Ni dots on the SrTiO3 NCs thin films deposited on n-Si, the Ni/SrTiO3 NCs/n-Si heterojunction devices were fabricated for the first time. The ideality factors of the twelve fabricated devices were vary from 1.05 to 1.22 and the barrier height values varied from 0.64 to 0.68 eV. Furthermore, since all devices yielded similar characteristics, only the current-voltage and the capacitance-voltage of one selected device (named H1) were investigated in detailed. The series resistance of this device was calculated as 96 Omega.

We address the composition-controlled synthesis of monodispersed AgPd alloy nanoparticles (NPs), their assembly for the first time on mesoporous graphitic carbon nitride (mpg-C3N4), and the unprecedented catalysis of mpg-C3N4@AgPd in the hydrolytic dehydrogenation of ammonia borane (AB) at room temperature. Monodispersed AgPd alloy NPs were synthesized using a high-temperature organic-phase surfactant-assisted protocol comprising the co-reduction of silver(I) acetate and palladium(II) acetylacetonate in the presence of oleylamine, oleic acid, and 1-octadecene. This protocol allowed the synthesis of four different compositions of AgPd alloy NPs. The AgPd alloy NPs were then assembled on mpg-C3N4, reduced graphene oxide, and Ketjenblack using a liquid-phase self-assembly method. Among the three supports tested, the mpg-C3N4@AgPd catalysts provided the best activity because of the Mott-Schottky effect, which was driven by the favorable work function difference between mpg-C3N4 and the metal NPs. Moreover, the activity of the mpg-C3N4@AgPd catalyst was further enhanced by an acetic acid treatment (AAt), and a record initial turnover frequency of 94.1 mol((hydrogen)).mol((catalyst))(-1).min(-1) was obtained. Furthermore, the mpg-C3N4@Ag42Pd58-AAt catalyst also showed moderate durability for the hydrolysis of AB. This study also includes a wealth of kinetic data for the mpg-C3N4@AgPd-catalyzed hydrolysis of AB.

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Addressed herein is the superior catalytic performance of reduced graphene oxide supported Ni30Pd70 alloy nanoparticles (rGO-Ni30Pd70) for the direct hydrogenation of alkenes and alkynes to alkanes, which surpasses the commercial Pd/C catalyst both in activity and stability. A variety of cyclic or aromatic alkenes and alkynes (a total of 17 examples) were rapidly reduced to the corresponding alkanes with high yields (>99%) via the presented direct hydrogenation protocol under ambient conditions. Compared to the commercially available Pd/C (10 wt%) catalyst, the rGO-Ni30Pd70 catalyst provided higher yields in shorter reaction times under the optimized conditions. Moreover, the rGO-Ni30Pd70 catalysts were more stable and durable than the commercial Pd/C catalysts by preserving their initial activity after five consecutive runs in the hydrogenation reactions.

Addressed herein is the preparation and the electrode performance of monodisperse CoFe2O4 nanoparticles (NPs) supported on Vulcan XC-72 for the Lithium-air battery (LAB) and Lithium-ion battery (LIB). Monodisperse CoFe2O4 NPs were synthesized by the thermal decomposition of cobalt(II) acetylacetonate and iron(III) acetylacetonate in oleylamine and oleic acid in the presence of 1,2-tetradecanediol and benzyl ether. As-prepared CoFe2O4 NPs with a particle size of 11 nm were then supported on Vulcan XC-72 (Vulcan-CoFe2O4) at different theoretical loadings (20, 40 and 60 wt % CoFe2O4 NPs) by using the simple liquid phase self assembly method. CoFe2O4 NPs dispersed on Vulcan-CoFe2O4 composites were characterized by transmission electron microscopy (TEM), powder X-ray diffraction (PXRD) and atomic absorption spectroscopy (AAS). The MS analyses indicated that the Vulcan-CoFe2O4 composites with different loadings were included 3.7, 8.1 and 16.4 wt % CoFe2O4 on the metal basis. The electrode performance of Vulcan-CoFe2O4 composites were evaluated as the anode active material for LIB and cathode active material for LABs by performing the galvanostatic charge-discharge tests. The highest discharge capacity for both LAB (7510 mAh g((Vulcan+CoFe2O4))(-1); 13380 mAh g(CoFe2O4)(-1) @ 0.1C) and LIB (863 mAh g((Vulcan+CoFe2O4))(-1); 9330 mAh g(CoFe2O4)(-1)@ 0.1C) was investigated with 16.4 wt % CoFe2O4. (c) 2015 Elsevier B.V. All rights reserved.

A novel and highly efficient heterogeneous catalytic reductive amination of aldehydes is described. The recently developed graphene supported NiPd alloy nanoparticle (G-NiPd) catalyst using ammonia borane (AB) as a green, stable and safe hydrogen donor was used in a water/methanol mixture (v/v=2/3) under ambient conditions. The catalytic system was successfully applied in the reductive amination of various substituted aldehydes with amines and the corresponding products were obtained in (up to) 99% yield in 6 h. The G-NiPd catalyst could be recycled up to five times without any significant loss in the product yield. (C) 2015 Elsevier B.V. All rights reserved.

Chemically derived graphene (CDG) was prepared by hydrazine hydrate reduction of graphene oxide and used as support for palladium nanoparticles (Pd NPs) generated ex situ with controllable particle size and dispersion. The Pd NPs supported on CDG were well characterized by using a combination of advance analytical techniques and employed as catalyst in the dehydrogenation and hydrolysis of ammonia borane (AB) in organic solvents and aqueous solutions, respectively. Monodisperse Pd NPs of 4.5 nm were prepared from the reduction of palladium(II) acetylacetonate by tert-butylamine borane in the presence of oleylamine. They were readily impregnated on CDG which. has BET surface area of 500 m(2) g(-1). Pd NPs retain their particle size dispersion and stability when supported on chemically derived graphene. The resulting materials are highly active and stable catalyst for the dehydrogenation and hydrolysis of AB. In addition to their high activity and stability, these Pd NPs are also reusable catalyst in both dehydrogenation and hydrolysis of AB preserving 85% and 95% of initial activity after 5th and 10th runs, respectively. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Monodisperse 7 nm CoPd nanoparticles (NPs) with controlled compositions were synthesized and studied for their catalyzing methanolysis of ammonia borane (AB). The NPs were prepared by the reduction of cobalt(II) acetylacetonate and palladium(II) bromide in the presence of oleylarnine and trioctylphosphine. Deposited on a carbon support without any specific surface treatment, these NPs were active catalysts for methanolysis of AB, and their activities were composition-dependent. Among all CoPd catalysts tested, Co48Pd52 NPs exhibited the highest catalytic activity and stability. Kinetic study showed that the catalytic methanolysis of AB was first-order with respect to catalyst concentration and zero-order with respect to AB concentration. The activation energy for the methanolysis was calculated to be 25.5 kJ mol(-1). These CoPd NPs are a promising catalyst for AB methanolysis and for developing a highly efficient hydrogen generation system for power applications.

Water soluble polymer stabilized iron(0) nanoclusters were prepared from the reduction of iron(III) chloride by sodium borohydride (SB) and ammonia borane (AB) mixture in the presence of polyethylene glycol (PEG) as stabilizer and ethylene glycol as solvent at 80 degrees C under nitrogen atmosphere. PEG stabilized iron(0) nanoclusters were isolated from the reaction solution by centrifugation and characterized by UV-Vis, TEM, HRTEM, XRD, ICP-OES and FT-IR methods. The particle size of PEG stabilized iron(0) nanoclusters ranges from 4.0 nm to 8.5 nm with a mean value of 6.3 nm. They are redispersible in water and yet highly active catalysts in hydrogen generation from the hydrolysis of SB and AB. They provide a turnover frequency of TOF = 6.2 and 6.4 min(-1) for the hydrolysis of SB and AB at 25.0 +/- 0.5 degrees C, respectively. The TOF values are the best ever reported for the iron catalysts and comparable to other non-noble metal catalyst systems in both hydrolysis reactions. Kinetics of hydrogen generation from the hydrolysis of AB in the presence of PEG stabilized iron(0) nanoclusters was also studied by varying the catalyst concentration, substrate concentration, and temperature. This is the first kinetic study on the hydrolysis of AB in the presence of an iron catalyst. Moreover, PEG stabilized iron(0) nanoclusters can be separated magnetically from the catalytic reaction solution using a magnet and show catalytic activity even after tenth run. (C) 2011 Elsevier B. V. All rights reserved.

Hydrogen phosphate (HPO4 (2-)) or poly(acrylic acid) (PAA) stabilized cobalt(0) nanoclusters were in situ generated from the reduction of cobalt(II) chloride during the catalytic hydrolysis of sodium borohydride (NaBH4) in the presence of stabilizers, HPO4 (2-) or PAA. Cobalt(0) nanoclusters stabilized by HPO4 (2-) or PAA were characterized by using UV-Visible spectroscopy, TEM, XPS and FT-IR techniques. They were employed as catalysts in the hydrolysis of NaBH4 to examine the effect of stabilizer type on their catalytic activity and stability. Detailed reaction kinetics of the hydrolysis of NaBH4 in the presence of both catalysts was studied depending on catalyst concentration, substrate concentration and temperature. PAA stabilized cobalt(0) nanoclusters provided higher total turnover number (TTON = 6,600) than that of HPO4 (2-) stabilized cobalt(0) nanoclusters (1,285 turnovers). However, the HPO4 (2-) stabilized cobalt(0) nanoclusters provided a lower activation energy (E (a) = 53 +/- A 2 kJ mol(-1)) than the PAA stabilized cobalt(0) nanoclusters (E (a) = 58 +/- A 2 kJ mol(-1)) for the hydrolysis of NaBH4. The use of two types of stabilizers in the preparation of the same metal(0) nanoclusters following the same methodology enables us to compare the electrostatic and steric stabilization in terms of the catalytic activity and stability of metal(0) nanoclusters.

Monodisperse 8 nm CoPd nanoparticles (NPs) with controlled compositions were synthesized by the reduction of cobalt acetylacetonate and palladium bromide in the presence of oleylamine and trioctylphosphine. These NPs were active catalysts for hydrogen generation from the hydrolysis of ammonia borane (AB), and their activities were composition dependent. Among the 8 nm CoPd catalysts tested for the hydrolysis of AB, the Co35Pd65 NPs exhibited the highest catalytic activity and durability. Their hydrolysis completion time and activation energy were 5.5 min and 27.5 kJ mol(-1), respectively, which were comparable to the best Pt-based catalyst reported. The catalytic performance of the CoPd/C could be further enhanced by a preannealing treatment at 300 degrees C under air for 15 h with the hydrolysis completion time reduced to 3.5 min. This high catalytic performance of Co35Pd65 NP catalyst makes it an exciting alternative in pursuit of practical implementation of AB as a hydrogen storage material for fuel cell applications.

Herein we report a new method for the synthesis and characterization of PVP-stabilized palladium(0) nanoclusters and their enhanced catalytic activity in Suzuki coupling and Heck reactions of aryl bromides with phenylboronic acid and styrene, respectively, under mild conditions. The PVP-stabilized palladium(0) nanoclusters with a particle size of 4.5 +/- 1.1 nm were prepared using a new method: refluxing a mixture of potassium tetrachloropalladate(II) and PVP in methanol at 80 degrees C for 1 h followed by reduction with sodium borohydride. Palladium(0) nanoclusters prepared in this way were stable in solution for weeks, could be isolated as solid materials and were characterized by TEM, XPS, UV-vis, and XRD techniques. The PVP-stabilized palladium(0) nanoclusters were active catalysts in Heck and Suzuki coupling reactions of arylbromides with styrene and phenylboronic acid affording stilbenes and biphenyls, respectively, in high yield. Recycling experiments showed that PVP-stabilized palladium(0) nanoclusters could be used five times with essentially no loss in activity in the Heck and Suzuki coupling reactions. Copyright (C) 2009 John Wiley & Sons, Ltd.

The effect of first-row transition metal nanoparticles as co-catalysts on the activity of mesoporous graphitic carbon nitride (m-gCN) and black phosphorous (BP) heterojunctions (m-gCN/BP) in the photocatalytic hydrogen evolution reaction (HER) is investigated comparatively. Three m-gCN/BP-M (M: Co, Ni, and Cu) ternary nanocomposites were prepared via wetness impregnation and chemical reduction of metal precursors on as-prepared m-gCN/BP binary heterojunctions. The photocatalytic HER activities of m-gCN, m-gCN/BP, m-gCN/BP-Ni, mgCN/BP-Co, and m-gCN/BP-Cu nanocomposites were determined to be 0.233, 0.330, 0.442, 0.326, and 0.223 mmol g-1 h-1, respectively, under visible light illumination. These results revealed that type of transition metal NPs as co-catalysts have considerable effect on the activity of m-gCN/BP heterojunctions in the photocatalytic HER, among which m-gCN/BP-Ni is the best one. The DFT calculations performed on the nanocomposites revealed that m-gCN/BP-Ni possesses the lowest band gap and the highest visible light absorption resulting in the highest photocatalytic activity in HER.