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water splitting

Minghao Yu, Dun Lin, Haobin Feng, Yinxiang Zeng, Yexiang Tong, Xihong Lu
The voltage of carbon-based aqueous supercapacitors is limited by the water splitting reaction occurring in one electrode, generally resulting in the promising but unused potential range of the other electrode. Exploiting this unused potential range provides the possibility for further boosting their energy density. An efficient surface charge control strategy was developed to remarkably enhance the energy density of multiscale porous carbon (MSPC) based aqueous symmetric supercapacitors (SSCs) by controllably tuning the operating potential range of MSPC electrodes...
March 27, 2017: Angewandte Chemie
Tatsuya Shinagawa, Marcus Tze-Kiat Ng, Kazuhiro Takanabe
The development of cost-effective and active water-splitting electrocatalysts that work at mild pH is an essential step towards the realization of sustainable energy and material circulation in our society. Its success requires a drastic improvement in the kinetics of the anodic half-reaction of the oxygen evolution reaction (OER), which determines the overall system efficiency to a large extent. A simple electrochemical protocol has been developed to activate Ni electrodes, by which a stable NiOOH phase was formed, which could weakly bind to alkali-metal cations...
March 27, 2017: Angewandte Chemie
Raquel Viana Rodrigues, Camila Sobral Sampaio, Rafael Rocha Pacheco, Fernanda Miori Pascon, Regina Maria Puppin-Rontani, Marcelo Giannini
STATEMENT OF PROBLEM: Glass fiber post cementation procedures have undergone significant development. Relining the post with composite resin is a technique that aims to reduce resin cement thickness and consequently problems inherent to polymerization. Evidence is sparse regarding the efficacy of bonding procedures at increasing depths (from cervical to apical) using different adhesive cementation techniques. PURPOSE: The purpose of this in vitro study was to evaluate the push-out bond strength (PBS) of composite resin relined glass fiber posts cemented to bovine root dentin using different adhesive cementation protocols...
March 23, 2017: Journal of Prosthetic Dentistry
Haohong Duan, Dongguo Li, Yan Tang, Yang He, Ji Shu Fang, Rongyue Wang, Haifeng Lv, Pietro P Lopes, Arvydas P Paulikas, Haoyi Li, Scott X Mao, Chong-Min Wang, Nenad M Markovic, Jun Li, Vojislav R Stamenkovic, Yadong Li
Search for active, stable and cost-efficient electrocataltysts for hydrogen production via water splitting could make substantial impact to the energy technologies that do not rely on fossil fuels. Here we report the synthesis of rhodium phosphide electrocatalyst with low metal loading in the form of nanocubes (NCs) dispersed in high surface area carbon (Rh2P/C) by a facile solvo-thermal approach. The Rh2P/C exhibit remarkable performance for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) compared to Rh/C and Pt/C catalysts...
March 26, 2017: Journal of the American Chemical Society
Daniele Narzi, Giuseppe Mattioli, Daniele Bovi, Leonardo Guidoni
The Mn4CaO5 cluster of Photosystem II promotes a crucial step in the oxygenic photosynthesis, namely, the water splitting reaction. The structure of such cluster in the S1 state of the Kok-Joliot's cycle has been recently resolved by femtosecond X-ray free electron laser (XFEL) measurements. However, the XFEL results are characterized by appreciable discrepancies with previous X-ray diffraction (XRD), as well as with S1 models based on ab initio calculations. We provide here a unifying picture based on a combined set of DFT-based structures and molecular dynamics simulations of the S0 and S1 states...
March 25, 2017: Chemistry: a European Journal
Viruthasalam Maruthapandian, Mahendran Mathankumar, Velu Saraswathy, Balasubramanian Subramanian, Srinivasan Muralidharan
Catalysts for the oxygen evolution reaction (OER) play an important role in the conversion of solar energy to fuel of earth abundant water into H2 and O2 through splitting/electrolyzer. The heterogeneous electrocatalysts for hydrogen and oxygen evolution reactions (HER and OER) exhibit catalytic activity that depends on the electronic properties, oxidation states and local surface structure. Spinel ferrites (MFe2O4; M = Ni and Co) based materials have been attractive for the catalytic water oxidation due to their well-known stability in alkaline medium, easy synthesis, existence of metal cations with various oxidation states, low cost and tunable properties by the desired metal substitution...
March 24, 2017: ACS Applied Materials & Interfaces
Pandian Ganesan, Sivanantham Arumugam, Sangaraju Shanmugam
One of the important challenges in alkaline water electrolysis are to utilize a bifunctional catalyst for both hydrogen evolution (HER) and oxygen evolution (OER) reactions to increase the efficiency of water splitting devices for the long durable operations. Herein, nickel-cobalt-titanium alloy directly grown on a high corrosion resistance titanium foil (NCT) by a simple, single and rapid electrochemical deposition at room temperature. The electrocatalytic activity of NCT alloy electrodes is evaluated for both HER and OER in aqueous electrolyte...
March 24, 2017: ACS Applied Materials & Interfaces
Yatin J Mange, Soundarrajan Chandrasekaran, Nathan Hollingsworth, Nicolas H Voelcker, Ivan P Parkin, Thomas Nann, Thomas J Macdonald
Metal organic {Ni₄O₄} clusters, known oxidation catalysts, have been shown to provide a valuable route in increasing the photocurrent response on silicon nanowire (SiNW) photocathodes. {Ni₄O₄} clusters have been paired with SiNWs to form a new photocathode composite for water splitting. Under AM1.5 conditions, the combination of {Ni₄O₄} clusters with SiNWs gave a current density of -16 mA/cm², which corresponds to an increase in current density of 60% when compared to bare SiNWs. The composite electrode was fully characterised and shown to be an efficient and stable photocathode for water splitting...
February 6, 2017: Nanomaterials
Tae Hyung Lee, Soo Young Kim, Ho Won Jang
A century after its first synthesis in 1914, black phosphorus has been attracting significant attention as a promising two-dimensional material in recent years due to its unique properties. Nowadays, with the development of its exfoliation method, there are extensive applications of black phosphorus in transistors, batteries and optoelectronics. Though, because of its hardship in mass production and stability problems, the potential of the black phosphorus in various fields is left unexplored. Here, we provide a comprehensive review of crystal structure, electronic, optical properties and synthesis of black phosphorus...
October 29, 2016: Nanomaterials
Qiang Zhang, Zhenyin Hai, Aoqun Jian, Hongyan Xu, Chenyang Xue, Shengbo Sang
p-Co₃O₄/n-TiO₂ nanoparticles (~400 nm) for photocatalysis were prepared via carbon assisted method and sol-gel method in this work. The paper also studied the application of visible light illuminated p-Co₃O₄/n-TiO₂ nanocomposites cocatalyst to the overall pure water splitting into H₂ and O₂. In addition, the H₂ evolution rate of the p-Co₃O₄/n-TiO₂ nanocomposites is 25% higher than that of the pure Co₃O₄ nanoparticles. Besides, according to the results of the characterizations, the scheme of visible light photocatalytic water splitting is proposed, the Co₃O₄ of the nanocomposites is excited by visible light, and the photo-generated electrons and holes existing on the conduction band of Co₃O₄ and valence band of TiO₂ have endowed the photocatalytic evolution of H₂ and O₂ with higher efficiency...
July 27, 2016: Nanomaterials
Desmond E Schipper, Zhenhuan Zhao, Andrew P Leitner, Lixin Xie, Fan Qin, Md Kamrul Alam, Shuo Chen, Dezhi Wang, Zhifeng Ren, Zhiming Wang, Jiming Bao, Kenton H Whitmire
A variety of catalysts have been developed for electrocatalytic oxygen evolution, but very few of them can be readily integrated with semiconducting light absorbers for photoelectrochemical or photocatalytic water splitting. Here, we demonstrate an efficient core/shell photoanode with a highly active oxygen evolution electrocatalyst shell (FeMnP) and semiconductor core (rutile TiO2) for photoelectrochemical oxygen evolution reaction (PEC-OER). Metal-organic chemical vapor deposition (MOCVD) from a single-source precursor was used to ensure good contact between the FeMnP and the TiO2...
March 23, 2017: ACS Nano
Jia Liu, Jinsong Wang, Bao Zhang, Yunjun Ruan, Lin Lv, Xiao Ji, Kui Xu, Ling Miao, Jianjun Jiang
Low cost and high efficient bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are intensively investigated for overall water splitting. Herein, we combined experimental researches with first-principles calculations based on density functional theory (DFT) to engineer the NiCo2S4@NiFe LDH heterostructures interface for enhancing overall water splitting activity. The DFT calculations exhibit a strong interaction and charge transfer between NiCo2S4 and NiFe LDH, which change the interfacial electronic structure and surface reactivity...
March 23, 2017: ACS Applied Materials & Interfaces
Markus Pichler, Jakub Szlachetko, Ivano Eligio Castelli, Nicola Marzari, Max Döbeli, Alexander Wokaun, Daniele Pergolesi, Thomas Lippert
The nitrogen substitution into the oxygen sites of several oxide materials leads to a reduction of the band gap to the visible light energy range, which makes these oxynitride semiconductors potential photocatalysts for efficient solar water splitting. Oxynitrides typically show a different crystal structure compare to the pristine oxide material. Since the band gap is correlated to both the chemical composition and the crystal structure, it is not trivial to distinguish what modifications of the electronic structure induced by the nitrogen substitution are related to compositional and/or structural effects...
March 23, 2017: ChemSusChem
Pengfei Li, Jianwei Lu, Wenfeng Hou, Yonghui Pan, Yang Wang, Muhammad Rizwan Khan, Tao Ren, Rihuan Cong, Xiaokun Li
Controlled release fertilizer can reduce nitrogen losses to the environment while increasing grain yield and improving apparent nitrogen recovery (ANR) of rice. However, few studies have evaluated the comparative efficacy of different polymer-coated urea products on nitrogen (N) losses, ANR, and N uptake of rice. A 2-year field experiment was conducted to compare the effects of three different types of polymer-coated urea fertilizer on nitrogen losses through NH3 volatilization and surface runoff to the environment, ANR, grain yield, and N uptake as compared to conventional urea of rice...
March 22, 2017: Environmental Science and Pollution Research International
Jun Li, Gengfeng Zheng
Hydrogen fuel acquisition based on electrochemical or photoelectrochemical water splitting represents one of the most promising means for the fast increase of global energy need, capable of offering a clean and sustainable energy resource with zero carbon footprints in the environment. The key to the success of this goal is the realization of robust earth-abundant materials and cost-effective reaction processes that can catalyze both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), with high efficiency and stability...
March 2017: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Daniel Leicht, Matin Kaufmann, Nitish Pal, Gerhard Schwaab, Martina Havenith
The infrared spectrum of allyl:water clusters embedded in helium nanodroplets was recorded. Allyl radicals were produced by flash vacuum pyrolysis and trapped in helium droplets. Deuterated water was added to the doped droplets, and the infrared spectrum of the radical water aggregates was recorded in the frequency range 2570-2820 cm(-1). Several absorption bands are observed and assigned to 1:1 and 1:2 allyl:D2O clusters, based on pressure dependent measurements and accompanying quantum chemical calculations...
March 21, 2017: Journal of Chemical Physics
Umer Saeed, Syed Aftab Wajid, Tasneem Khaliq, Zahir Ahmad Zahir
Nitrogen fertilizer availability to plants is strongly linked with water availability. Excessive or insufficient use of nitrogen can cause reduction in grain yield of wheat and environmental issues. The per capita per annum water availability in Pakistan has reduced to less than 1000 m(3) and is expected to reach 800 m(3) during 2025. Irrigating crops with 3 or more than 3 in. of depth without measuring volume of water is not a feasible option anymore. Water productivity and economic return of grain yield can be improved by efficient management of water and nitrogen fertilizer...
March 21, 2017: Environmental Science and Pollution Research International
Miao Zhong, Takashi Hisatomi, Yutaka Sasaki, Sayaka Suzuki, Katsuya Teshima, Mamiko Nakabayashi, Naoya Shibata, Hiroshi Nishiyama, Masao Katayama, Taro Yamada, Kazunari Domen
Ta3 N5 is a very promising photocatalyst for solar water splitting because of its wide spectrum solar energy utilization up to 600 nm and suitable energy band position straddling the water splitting redox reactions. However, its development has long been impeded by poor compatibility with electrolytes. Herein, we demonstrate a simple sputtering-nitridation process to fabricate high-performance Ta3 N5 film photoanodes owing to successful synthesis of the vital TaOδ precursors. An effective GaN coating strategy is developed to remarkably stabilize Ta3 N5 by forming a crystalline nitride-on-nitride structure with an improved nitride/electrolyte interface...
March 21, 2017: Angewandte Chemie
Yecan Pi, Qi Shao, Pengtang Wang, Fan Lv, Shaojun Guo, Jun Guo, Xiaoqing Huang
Trimetallic oxyhydroxides are one of the most effective materials for oxygen evolution reaction (OER) catalysis, a key process for water splitting. Herein, we describe a facile wet-chemical method to directly grow a series of coralloid trimetallic oxyhydroxides on arbitrary substrates such as nickel foam (NF) and carbon nanotubes (CNTs). The amount of iron in these oxyhydroxide sponges on NF and CNTs was precisely controlled, revealing that the electrocatalytic activity of the WCoFe trimetallic oxyhydroxides depends on the Fe amount in a volcano-like fashion...
March 21, 2017: Angewandte Chemie
Fazalurahman Kuttassery, Siby Mathew, Shogo Sagawa, Sebastian Nybin Remello, Arun Thomas, Daisuke Yamamoto, Satomi Onuki, Yu Nabetani, Hiroshi Tachibana, Haruo Inoue
We report here a new molecular catalyst for efficient water splitting, aluminum porphyrins (tetra-methylpyridiniumylporphyrinatealuminum: AlTMPyP), containing the Earth's most abundant metal as the central ion. One-electron oxidation of the aluminum porphyrin initiates the two-electron oxidation of water to form hydrogen peroxide as the primary reaction product with the lowest known overpotential (97 mV). The aluminum-peroxo complex was clearly detected by a cold-spray ionization mass-spectrometry in HRMS mode and the structure of the intermediate was further confirmed using laser-Raman spectroscopy, indicating the hydroperoxy complex of AlTMPyP to be the key intermediate in the reaction...
March 20, 2017: ChemSusChem
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