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https://www.readbyqxmd.com/read/28820214/mediated-water-electrolysis-in-biphasic-systems
#1
Micheál D Scanlon, Pekka Peljo, Lucie Rivier, Heron Vrubel, Hubert H Girault
The concept of efficient electrolysis by linking photoelectrochemical biphasic H2 evolution and water oxidation processes in the cathodic and anodic compartments of an H-cell, respectively, is introduced. Overpotentials at the cathode and anode are minimised by incorporating light-driven elements into both biphasic reactions. The concepts viability is demonstrated by electrochemical H2 production from water splitting utilising a polarised water-organic interface in the cathodic compartment of a prototype H-cell...
August 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28819665/efficient-photoelectrochemical-water-splitting-on-ultrasmall-defect-rich-taox-nanoclusters-enhanced-by-size-selected-pt-nanocluster-promoters
#2
Saurabh Srivastava, Joseph Palathinkal Thomas, Nina Heinig, Marwa Abd-Ellah, Md Anisur Rahman, Kam Tong Leung
Formation of nanoclusters has attracted a lot of attention in recent years because of their distinct properties from isolated atoms and bulk solids. Here, we focus on the catalytic properties of supported transition metal oxide nanoclusters, such as TaO2, with a well-defined size distribution below 10 nm. We show that their catalytic performance can be greatly enhanced by introducing a reaction promoter such as Pt. Different combinations of precisely size-selected, defect-rich TaOx and Pt nanoclusters are produced by a gas-phase aggregation technique in a special DC magnetron sputtering system...
August 18, 2017: Nanoscale
https://www.readbyqxmd.com/read/28819660/nanostructured-materials-on-3d-nickel-foam-as-electrocatalysts-for-water-splitting
#3
REVIEW
Nitin K Chaudhari, Haneul Jin, Byeongyoon Kim, Kwangyeol Lee
Highly efficient and low-cost electrocatalysts are essential for water spitting via electrolysis in an economically viable fashion. However, the best catalytic performance is found with noble metal-based electrocatalysts, which presents a formidable obstacle for the commercial success of electrolytic water splitting-based H2 production due to their relatively high cost and scarcity. Therefore, the development of alternative inexpensive earth-abundant electrode materials with excellent electrocatalytic properties is of great urgency...
August 18, 2017: Nanoscale
https://www.readbyqxmd.com/read/28819153/giant-onsite-electronic-entropy-enhances-the-performance-of-ceria-for-water-splitting
#4
S Shahab Naghavi, Antoine A Emery, Heine A Hansen, Fei Zhou, Vidvuds Ozolins, Chris Wolverton
Previous studies have shown that a large solid-state entropy of reduction increases the thermodynamic efficiency of metal oxides, such as ceria, for two-step thermochemical water splitting cycles. In this context, the configurational entropy arising from oxygen off-stoichiometry in the oxide, has been the focus of most previous work. Here we report a different source of entropy, the onsite electronic configurational entropy, arising from coupling between orbital and spin angular momenta in lanthanide f orbitals...
August 18, 2017: Nature Communications
https://www.readbyqxmd.com/read/28819147/nitrogen-starvation-impacts-the-photosynthetic-performance-of-porphyridium-cruentum-as-revealed-by-chlorophyll-a-fluorescence
#5
Long-Sheng Zhao, Kang Li, Qian-Min Wang, Xiao-Yan Song, Hai-Nan Su, Bin-Bin Xie, Xi-Ying Zhang, Feng Huang, Xiu-Lan Chen, Bai-Cheng Zhou, Yu-Zhong Zhang
Nitrogen is one of the most important nutrients needed for plants and algae to survive, and the photosynthetic ability of algae is related to nitrogen abundance. Red algae are unique photosynthetic eukaryotic organisms in the evolution of algae, as they contain phycobilisomes (PBSs) on their thylakoid membranes. In this report, the in vivo chlorophyll (Chl) a fluorescence kinetics of nitrogen-starved Porphyridium cruentum were analyzed to determine the effects of nitrogen deficiency on photosynthetic performance using a multi-color pulse amplitude modulation (PAM) chlorophyll fluorometer...
August 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28817772/quantifying-elucidating-thermally-enhanced-minority-carrier-diffusion-length-using-radius-controlled-rutile-nanowires
#6
Liming Zhang, Litianqi Sun, Zixuan Guan, Sang Chul Lee, Yingzhou Li, Haitao Dean Deng, Yiyang Li, Nadia Ahlborg, Madhur Boloor, Nicholas A Melosh, William C Chueh
Minority carrier diffusion length (LD) is a crucial property that determines the performance of light absorbers in photoelectrochemical (PEC) cells. Many transition-metal oxides are stable photoanodes for solar water splitting but exhibit a small to moderate LD, ranging from a few nanometers (such as α-Fe2O3 and TiO2) to a few tens of nanometers (such as BiVO4). Under operating conditions, temperature of PEC cells can deviate substantially from ambient, yet the temperature-dependence of LD has not been quantified...
August 17, 2017: Nano Letters
https://www.readbyqxmd.com/read/28815868/conceptual-considerations-on-exposure-assessment-goals-for-aquatic-pesticide-risks-at-eu-level
#7
Jos J T I Boesten
BACKGROUND: The assessment of the risk to aquatic organisms is an important aspect of pesticide registration. This assessment has to be based on well-defined exposure assessment goals (EAGs). However, these goals have not yet been defined for the EU authorisation procedure. RESULTS: The definition of an aquatic EAG consists of seven elements including the type of water body, the spatial dimension of this body, the spatial population of water bodies, the multi-year temporal population of concentrations for a single water body, and the space-time percentile combination to be selected from the spatio-temporal population of concentrations...
August 16, 2017: Pest Management Science
https://www.readbyqxmd.com/read/28813595/activation-of-a-nickel-based-oer-catalyst-on-a-hematite-photoanode-via-incorporation-of-cerium-for-photoelectrochemical-water-oxidation
#8
Hyungseob Lim, Jae Young Kim, Edward J Evans, Amritesh Rai, Jun-Hyuk Kim, Bryan R Wygant, Charles Buddie Mullins
There has been debate on whether Ni(OH)2 is truly catalytically active for the photo/-electrocatalytic oxygen evolution reaction. In this report, we have synthesized a Ni(OH)2 co-catalyst on a hematite photoanode and showed that, as has been proposed in other studies, the current density varies as a function of scan rate, which arise due to a photo-induced capacitive charging effect. We have discovered that this photo-induced charging of Ni2+/3+ can be overcome by mixing cerium nitrate into the Ni precursor solution...
August 16, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28811518/anomalous-in-situ-activation-of-carbon-supported-ni2p-nanoparticles-for-oxygen-evolving-electrocatalysis-in-alkaline-media
#9
Young-Hoon Chung, Injoon Jang, Jue-Hyuk Jang, Hyun S Park, Hyung Chul Ham, Jong Hyun Jang, Yong-Kul Lee, Sung Jong Yoo
Electrochemical water splitting is one of the most promising systems by which to store energy produced from sustainable sources, such as solar and wind energy. Designing robust and stable electrocatalysts is urgently needed because of the relatively sluggish kinetics of the anodic reaction, i.e. the oxygen evolution reaction (OER). In this study, we investigate the anomalous in situ activation behaviour of carbon-supported Ni2P nanoparticles (Ni2P/C) during OER catalysis in alkaline media. The activated Ni2P/C shows an exceptionally high activity and stability under OER conditions in which the overpotential needed to achieve 10 mA cm(-2) was reduced from approximately 350 mV to approximately 300 mV after 8,000 cyclic voltammetric scans...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28810778/hydrogen-bond-network-rearrangement-dynamics-in-water-clusters-effects-of-intermolecular-vibrational-excitation-on-tunneling-rates
#10
William T S Cole, Richard J Saykally
Theoretical studies of hydrogen bond network rearrangement (HBNR) dynamics in liquid water have indicated that librational motions initiate the hydrogen bond breaking/formation processes. We present the results of using a simple time evolution method to extract and compare the tunneling lifetimes for motions that break and reform the hydrogen bond for the water dimer, trimer, and pentamer from the experimentally measured tunneling splittings in the ground and excited intermolecular vibrational states. We find that the specific nature of the intermolecular vibrational excitation does not significantly influence the tunneling lifetime of the dimer, but that only excitations to a librational vibration affect the water trimer and pentamer lifetimes...
August 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28810743/layer-by-layer-molecular-assemblies-for-dye-sensitized-pho-toelectrosynthesis-cells-prepared-by-atomic-layer-deposi-tion
#11
Degao Wang, Matthew V Sheridan, Bing Shan, Byron H Farnum, Seth L Marquard, Benjamin D Sherman, Michael S Eberhart, Animesh Nayak, Christopher Dares, Atanu Das, R Morris Bullock, Thomas J Meyer
In a Dye Sensitized Photoelectrosynthesis Cell (DSPEC) the relative orientation of the catalyst and chromophore plays an important role in determining the device efficiency. Here we introduce a new, robust atomic layer deposition (ALD) procedure for the preparation of molecular chromophore-catalyst assemblies on wide bandgap semiconductors. In this procedure, solution deposited, phosphonate derivatized metal complexes on metal oxide surfaces are treated with reactive metal reagents in the gas phase by ALD to form an outer metal ion bridging group which can bind a second phosphonate containing species from solution to establish a R1-PO2-O-M-O-PO2-R2 type surface assembly...
August 15, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28809983/controllable-synthesis-of-inorganic-organic-zn1-xcdxs-deta-solid-solution-nanoflowers-and-their-enhanced-visible-light-photocatalytic-hydrogen-production-performance
#12
Jiali Lv, Jinfeng Zhang, Kai Dai, Changhao Liang, Guangping Zhu, Zhongliao Wang, Zhen Li
Sustainable photocatalytic hydrogen evolution (PHE) of water splitting has been utilized to solve the serious environmental pollution and energy shortage problems over the last decade. Inorganic-organic hybrid materials could combine the organic molecules and functional inorganic blocks into unique materials through complicated physical and chemical interactions. In this paper, diethylenetriamine (DETA) was used as an organic molecule template for the synthesis of inorganic-organic Zn1-xCdxS-DETA solid solution nanoflowers (NFs) at very low temperature...
August 15, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28809076/fe-doped-ni3c-nanodots-in-n-doped-carbon-nanosheets-for-efficient-hydrogen-evolution-and-oxygen-evolution-electrocatalyst
#13
Qingyu Yan, Hasen Fan, Hong Yu, Yufei Zhang, Yun Zheng, Zhengfei Dai, Yubo Luo, Bing Li, Yun Zong
Uniform Ni3C nanodots dispersed in ultrathin N-doped carbon nanosheets were successfully prepared by carburization of the two dimensional (2D) nickel-cyanide coordination polymer precursors. The Ni3C based nanosheets have lateral length of about 200 nm and thickness of 10 nm. When doped with Fe, the Ni3C based nanosheets exhibited outstanding electrocatalytic properties for both hydrogen evolution reactions (HER) and oxygen evolution reactions (OER). For example, 2 at% Fe (atomic percent) doped Ni3C nanosheets depict a low overpotential (292 mV) and a small Tafel slope (41...
August 14, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28801934/self-co-catalyzed-fluorine-doped-hematite-nanocrystal-for-efficient-water-oxidation
#14
Yi Xie, Junfeng Xie, Weiwei Liu, Jianping Xin, Fengcai Lei, Li Gao, Haichao Qu, Xiaodong Zhang
Herein, enhanced light absorption and oxygen-evolving activity were simultaneously achieved by doping fluorine anions into hematite nanocrystals. With the merits of anion doping, the band structure of hematite can be effectively regulated, leading to the generation of defect level between the bandgap and remarkably increased visible light absorption. In addition, the activity for electrocatalytic oxygen evolution reaction (OER) of the hematite nanocrystals exhibits obvious enhancement after fluorine doping, making the doped hematite play as an effective self-co-catalyst for photoelectrochemical water splitting...
August 12, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28800240/an-optically-and-electrochemically-decoupled-monolithic-photoelectrochemical-cell-for-high-performance-solar-driven-water-splitting
#15
Seungtaeg Oh, Hakhyeon Song, Jihun Oh
Photoelectrochemical (PEC) cells have attracted much attention as a viable route for storing solar energy and producing value-added chemicals and fuels. However, the competition between light absorption and electrocatalysis at a restrained cocatalyst area on conventional planar-type photoelectrodes could limit their conversion efficiency. Here, we demonstrate a new monolithic photoelectrode architecture that eliminate the optical-electrochemical coupling by forming locally nanostructured cocatalysts on a photoelectrode...
August 17, 2017: Nano Letters
https://www.readbyqxmd.com/read/28799586/elucidating-the-impact-of-a-site-cation-change-on-photocatalytic-h2-and-o2-evolution-activities-of-perovskite-type-lntaon2-ln-la-and-pr
#16
Mirabbos Hojamberdiev, Maged F Bekheet, Judy N Hart, Junie Jhon M Vequizo, Akira Yamakata, Kunio Yubuta, Aleksander Gurlo, Masashi Hasegawa, Kazunari Domen, Katsuya Teshima
Transition metal (oxy)nitrides with perovskite-type structures have been regarded as one of the promising classes of inorganic semiconductor materials that can be used in solar water splitting systems for the production of hydrogen as a renewable and storable energy carrier. The performance of transition metal (oxy)nitrides in solar water splitting is strongly influenced by the crystal structure-related dynamics of photogenerated charge carriers. Here, we have systematically assessed the influence of A-site cation exchange on the visible-light-induced photocatalytic H2 and O2 evolution activities, photoanodic response, and dynamics of photogenerated charge carriers of perovskite-type LnTaON2 (Ln = La and Pr)...
August 11, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28799330/imaging-dynamic-collision-and-oxidation-of-single-silver-nanoparticles-at-the-electrode-solution-interface
#17
Rui Hao, Yunshan Fan, Bo Zhang
The electrochemical interface is an ultrathin interfacial region between the electrode surface and the electrolyte solution and is often characterized by numerous dynamic processes, such as solvation and desolvation, heterogeneous electron transfer, molecular adsorption and desorption, diffusion, and surface rearrangement. Many of these processes are driven and modulated by the presence of a large interfacial potential gradient. The study and better understanding of the electrochemical interface is important for designing better electrochemical systems where their applications may include batteries, fuel cells, electrocatalytic water splitting, corrosion protection, and electroplating...
August 11, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28797753/molybdenum-doped-zns-sheets-with-dominant-111-facets-for-enhanced-visible-light-photocatalytic-activities
#18
Rongbin Zhang, Biao Du, Lichang Yin, Yuanquan Miao, Jianxin Cai, Gang Feng, Xuewen Wang
ZnS is widely used as a semiconductor photocatalyst in photo-electrochemical water splitting and photodegradation under ultraviolet (UV)-light irradiation. In this work, Molybdenum (Mo)-doped ZnS sheets with dominant {111} facets are developed using a hydrothermal method with Mo ions as precursors to realize non-visible-light photocatalytic activity and reduce the recombination rate of photoexcited carriers in ZnS. Mo ions are found to play a key role in the growth process of the sheet-like structure. Mo-dopants in the ZnS sheets introduce the acceptor energy levels among the bandgaps...
August 2, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28797164/universal-surface-engineering-of-transition-metals-for-superior-electrocatalytic-hydrogen-evolution-in-neutral-water
#19
Bo You, Xuan Liu, Guoxiang Hu, Sheraz Gul, Junko Yano, De-En Jiang, Yujie Sun
The development of low-cost hybrid water splitting-biosynthetic systems that mimic natural photosynthesis to achieve solar-to-chemical conversion is of great promise for future energy demands, but often limited by the kinetically sluggish H2 evolu-tion reaction (HER) on the surface of nonprecious transition metal catalysts in neutral media. It is thus highly desirable to rationally tailor the reaction interface to boost the neutral HER catalytic kinetics. Herein, we report a general surface nitro-gen modification of diverse transition metals (e...
August 10, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28796474/co-nanoparticles-co-n-s-tri-doped-graphene-templated-from-in-situ-formed-co-s-co-doped-g-c3n4-as-an-active-bifunctional-electrocatalyst-for-overall-water-splitting
#20
Geng Zhang, Ping Wang, Wang-Ting Lu, Cao-Yu Wang, Yong-Ke Li, Cong Ding, Jiangjiang Gu, Xin-Sheng Zheng, Fei-Fei Cao
The development of high-performance electrocatalyst with earth-abundant elements for water-splitting is a key factor to improve its cost efficiency. Here, a noble metal free bi-functional electrocatalyst was synthesized by a facile pyrolysis method using sucrose, urea, Co(NO3)2 and sulfur powder as raw materials. During the fabrication process, Co, S co-doped graphitic carbon nitride (g-C3N4) was firstly produced, and then this in-situ formed template further induced the generation of a Co, N, S tri-doped graphene coupled with Co nanoparticles...
August 10, 2017: ACS Applied Materials & Interfaces
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