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| Open AccessNanoscale membranes that chemically isolate and electronically wire up the abiotic/biotic interface
Bioelectrochemical cells have huge potential, yet incompatibilities between the microbe and abiotic catalysts can affect efficiency. Here, the authors report the development of thin silica membranes with bridging molecular wires that chemically separate yet electrically connect the two components.
- Jose A. Cornejo
- , Hua Sheng
- & Heinz Frei
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| Open AccessNanoscale kinetics of asymmetrical corrosion in core-shell nanoparticles
Understanding how catalysts corrode during use is crucial in developing new, durable devices. Here, the authors studied the real-time corrosion of core-shell palladium-platinum nanocubes by electron microscopy and found two competitive etching mechanisms to dominate catalyst degradation behavior.
- Hao Shan
- , Wenpei Gao
- & Jianbo Wu
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| Open AccessDual properties of a hydrogen oxidation Ni-catalyst entrapped within a polymer promote self-defense against oxygen
Bio-inspired Ni-based molecular catalysts are efficient for H2 oxidation, but are suffering from the poor stability in the presence of O2. Here, the authors develop a strategy to boost greatly their stability by dispersing them in a hydrophobic and redox-silent polymer matrix.
- Alaa A. Oughli
- , Adrian Ruff
- & Olaf Rüdiger
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| Open AccessRegulating p-block metals in perovskite nanodots for efficient electrocatalytic water oxidation
Electrocatalysts that possess high densities of surface defects show great promise for efficient water oxidation. Here the authors demonstrate that regulating the p-block metal content in perovskite nanodots imparts these materials with abundant surface defects and excellent electrocatalytic activity.
- Bo-Quan Li
- , Zi-Jing Xia
- & Qiang Zhang
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| Open AccessIdentification of catalytic sites in cobalt-nitrogen-carbon materials for the oxygen reduction reaction
Nitrogen-doped carbon materials with atomically dispersed iron or cobalt are promising for catalytic use. Here, the authors show that cobalt moieties have a higher redox potential, bind oxygen more weakly and are less active toward oxygen reduction than their iron counterpart, despite similar coordination.
- Andrea Zitolo
- , Nastaran Ranjbar-Sahraie
- & Frédéric Jaouen
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| Open AccessEvidence for percolation diffusion of cations and reordering in disordered pyrochlore from accelerated molecular dynamics
Diffusion plays an important role in sintering, damage tolerance and transport. Here authors perform classical and accelerated molecular dynamics simulations of vacancy-mediated cation diffusion in Gd2Ti2O7 pyrochlore and report non-monotonic evolution of cation diffusivity.
- Romain Perriot
- , Blas P. Uberuaga
- & Arthur F. Voter
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| Open AccessDurable and self-hydrating tungsten carbide-based composite polymer electrolyte membrane fuel cells
The proton conductivity of polymer electrolyte membranes in fuel cells dictates their performance, but requires sufficient water management. Here, the authors report a simple method to produce well-dispersed transition metal carbide nanoparticles as additives to enhance the performance of Nafion membranes in fuel cells.
- Weiqing Zheng
- , Liang Wang
- & Dionisios G. Vlachos
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| Open AccessIn situ atomic-scale observation of oxygen-driven core-shell formation in Pt3Co nanoparticles
Core-shell platinum alloy nanoparticles are promising catalysts for oxygen reduction, however a deeper understanding of core-shell formation is still required. Here the authors report oxygen-driven formation of core-shell Pt3Co nanoparticles, seen at the atomic scale with in situ electron microscopy at ambient pressure.
- Sheng Dai
- , Yuan You
- & Xiaoqing Pan
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| Open AccessHigh performance platinum single atom electrocatalyst for oxygen reduction reaction
High-performance electrocatalysts for the oxygen reduction reaction (ORR) typically use platinum (Pt), however its high cost is a hindrance to commercial scale up. Here, the authors report a cost-effective, efficient and durable Pt single-atom electrocatalyst for ORR with a Pt utilization of 0.13 gPt kW−1in a fuel cell.
- Jing Liu
- , Menggai Jiao
- & Gongquan Sun
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Article
| Open AccessExsolution trends and co-segregation aspects of self-grown catalyst nanoparticles in perovskites
Exsolution of transition metals from perovskites provides an effective route to useful catalysts, but the underlying factors governing exsolution remain poorly understood. Here, the authors find trends in exsolution in layered perovskites, showing that co-segregation of B-site dopant and oxygen vacancies plays a central role.
- Ohhun Kwon
- , Sivaprakash Sengodan
- & Guntae Kim
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| Open AccessElectronic metal-support interaction enhanced oxygen reduction activity and stability of boron carbide supported platinum
D-band engineering via alloying platinum is a leading design principle for advanced oxygen reduction electrocatalysts, but stability remains a concern. Here the authors make Pt nanoparticles supported on graphite-rich boron carbide for enhanced activity and stability, isolating and optimizing the electronic metal-support interactions.
- Colleen Jackson
- , Graham T. Smith
- & Denis Kramer
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Article
| Open AccessOrdered hydroxyls on Ca3Ru2O7(001)
As ternary perovskite-type oxides are increasingly used in fuel cells and catalysis, greater understanding of their surface chemical properties is required. Here the authors report a pronounced ordering of hydroxyls on the cleaved (001) surface of Ca3Ru2O7 perovskite induced by O-octahedral rotation and tilt.
- Daniel Halwidl
- , Wernfried Mayr-Schmölzer
- & Ulrike Diebold
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Article
| Open AccessElectricity from methane by reversing methanogenesis
Microbial fuel cells generate electricity from a variety of sources, however from methane only negligible electrical power has been reported so far. Here the authors convert methane into electricity using a synthetic consortium consisting of an engineered archaeal strain, microorganisms from methane-acclimated sludge, andGeobacter sulfurreducens.
- Michael J. McAnulty
- , Venkata G. Poosarla
- & Thomas K. Wood
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| Open AccessScalable and efficient separation of hydrogen isotopes using graphene-based electrochemical pumping
Thousands of tons of water are processed every year for hydrogen isotope separation, using extremely costly technology. Here the authors demonstrate a fully-scalable graphene electrochemical pump, which promises to dramatically reduce the energy and capital costs.
- M. Lozada-Hidalgo
- , S. Zhang
- & A. K. Geim
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| Open AccessEnhancing CO2 electrolysis through synergistic control of non-stoichiometry and doping to tune cathode surface structures
Carbon dioxide electrolysers are promising for chemical storage of renewable electricity; however, achieving effective adsorption/activation of CO2 is still an issue. Here the authors make a perovskite titanate cathode where non-stoichiometry and chemical doping are used to tune the surface structures, facilitating CO2reduction.
- Lingting Ye
- , Minyi Zhang
- & Kui Xie
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| Open AccessDemonstrating the potential of yttrium-doped barium zirconate electrolyte for high-performance fuel cells
Protonic ceramic fuel cells are promising for energy applications, but maintaining high performance with long-term stability is an issue. Here the authors use a stable yttrium-doped barium zirconate electrolyte, achieving a power output one order of magnitude higher than existing protonic ceramic fuel cells.
- Kiho Bae
- , Dong Young Jang
- & Joon Hyung Shim
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| Open AccessIn situ electrochemical quantification of active sites in Fe–N/C non-precious metal catalysts
Fe-N/C catalysts show surprising activity towards oxygen reduction in fuel cells. However, there is significant uncertainty as to the structure of the active site. Here, the authors quantify the number and turnover frequency of the active sites by reversibly blocking those sites with nitrite (NO2¯).
- Daniel Malko
- , Anthony Kucernak
- & Thiago Lopes
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| Open AccessIdentification of carbon-encapsulated iron nanoparticles as active species in non-precious metal oxygen reduction catalysts
Determining active species in non-precious metal catalysts for the oxygen reduction reaction remains a challenge due to catalyst heterogeneity. Here the authors perform gas-phase treatments on an iron-based catalyst to allow the identification of carbon-encapsulated iron nanoparticles as the active species.
- Jason A. Varnell
- , Edmund C. M. Tse
- & Andrew A. Gewirth
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| Open AccessSeawater usable for production and consumption of hydrogen peroxide as a solar fuel
The generation and storage of energy from renewable sources with robust and accessible technology is of significant and growing concern. Here, the authors demonstrate the solar generation of hydrogen peroxide from seawater as a viable route towards this important goal.
- Kentaro Mase
- , Masaki Yoneda
- & Shunichi Fukuzumi
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| Open AccessNickel supported on nitrogen-doped carbon nanotubes as hydrogen oxidation reaction catalyst in alkaline electrolyte
Cheap and efficient hydrogen oxidation catalysts are needed for low cost hydroxide exchange membrane fuel cells. Here, the authors report that nickel nanoparticles supported on nitrogen doped carbon nanotubes have hydrogen oxidation activity similar to platinum-group-metals in alkaline electrolyte.
- Zhongbin Zhuang
- , Stephen A. Giles
- & Yushan Yan
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| Open AccessMultiplex lithography for multilevel multiscale architectures and its application to polymer electrolyte membrane fuel cell
Multiplex lithography is a technique that can be used to fabricate complex soft materials. Here, the authors develop a method to prepare multilevel multiscale structures and demonstrate its application on polymer electrolyte membrane fuel cells which display decreased membrane resistance and increased electrochemical active surface area.
- Hyesung Cho
- , Sang Moon Kim
- & Mansoo Choi
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| Open AccessAntimony-doped graphene nanoplatelets
Heteroatom doping of graphitic networks has been shown to modify electrocatalytic performance. Here, the authors fabricate semimetal antimony doped graphene nanoplatelet based catalysts and demonstrate their enhanced stability for oxygen reduction, due to the multiple accessible antimony oxidation states.
- In-Yup Jeon
- , Min Choi
- & Jong-Beom Baek
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Three-dimensional analysis of Nafion layers in fuel cell electrodes
In proton exchange membrane fuel cells, little is known about distribution of ionomers inside electrodes. Here, the authors present an electron tomography technique that allows a three dimensional visualization and quantitative analysis of ionomer layers in the electrodes.
- M. Lopez-Haro
- , L. Guétaz
- & G. Gebel
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Tailoring gadolinium-doped ceria-based solid oxide fuel cells to achieve 2 W cm−2 at 550 °C
In low-temperature solid oxide fuel cells, power losses due to large ohmic resistances and activation barriers of ion transport are a common problem. Here, Lee et al. report a gadolinium-doped ceria-based solid oxide fuel cell, which overcomes the problem and achieves a power density of 2 W cm−2.
- Jin Goo Lee
- , Jeong Ho Park
- & Yong Gun Shul
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High-power biofuel cell textiles from woven biscrolled carbon nanotube yarns
Biofuel cells can be used as power sources for implantable biomedical devices, but suffer from limited power and lifetime. Here, Kwon et al.fabricate biscrolled carbon nanotube yarn electrodes, and demonstrate high fuel cell performances when used for glucose energy harvesting.
- Cheong Hoon Kwon
- , Sung-Ho Lee
- & Seon Jeong Kim
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Solar-induced direct biomass-to-electricity hybrid fuel cell using polyoxometalates as photocatalyst and charge carrier
The direct conversion of biomass to electricity is an important process. Here, the authors use polyoxometallates as both photocatalyst and charge carrier to generate electricity in a solar-powered hybrid fuel cell that can consume natural biomass, such as cellulose or wood powders, at low temperature.
- Wei Liu
- , Wei Mu
- & Yulin Deng
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Direct observation of the oxygenated species during oxygen reduction on a platinum fuel cell cathode
Understanding the oxygen reduction reaction at fuel cell cathodes requires information on adsorbed oxygenated species. Sanchez Casalongue et al. report in situidentification of oxygenated intermediates at cathodes and establish a correlation between the cathode potential and the surface speciation.
- Hernan Sanchez Casalongue
- , Sarp Kaya
- & Hirohito Ogasawara
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Ordered bilayer ruthenium–platinum core-shell nanoparticles as carbon monoxide-tolerant fuel cell catalysts
Ruthenium can alleviate poisoning effects of carbon monoxide on platinum catalysts, but is prone to dissolution in fuel cells. Hsieh et al.synthesize ordered ruthenium–platinum nanoparticles with well-defined platinum bilayer shells, leading to high carbon monoxide tolerance and superior durability.
- Yu-Chi Hsieh
- , Yu Zhang
- & Jia X Wang
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Ordered macroporous platinum electrode and enhanced mass transfer in fuel cells using inverse opal structure
Inverse opal structures are desirable for fuel cell electrodes, but application of such structures in polymer electrolyte membrane fuel cells is yet to be realised. Kimet al.report fabrication of a platinum catalyst layer with an inverse opal structure, and show improved fuel cell performance.
- Ok-Hee Kim
- , Yong-Hun Cho
- & Yung-Eun Sung
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Highly stable Pt monolayer on PdAu nanoparticle electrocatalysts for the oxygen reduction reaction
Platinum is used as a cathode in fuel cells but undergoes dissolution during potential changes, hindering commercial application in electric vehicles. Sasakiet al.report a new class of stable electrocatalysts that consist of platinum monolayers on palladium–gold alloy nanoparticles.
- Kotaro Sasaki
- , Hideo Naohara
- & Radoslav R. Adzic
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Iron-based cathode catalyst with enhanced power density in polymer electrolyte membrane fuel cells
Replacing platinum in polymer-electrolyte-membrane fuel cells with iron-based catalysts could provide low-cost power generators, but often leads to low power densities. Here, a new iron-based cathode catalyst is developed with enhanced power density, volumetric activity and mass-transport properties.
- Eric Proietti
- , Frédéric Jaouen
- & Jean-Pol Dodelet
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| Open AccessPromotion of water-mediated carbon removal by nanostructured barium oxide/nickel interfaces in solid oxide fuel cells
Anodes composed of nickel/yttria-stabilized zirconia in solid oxide fuel cells are known to suffer from coking, which reduces their performance. Here, Yang and colleagues report a new barium oxide/nickel anode, which efficiently oxidizes fuel with minimum carbon buildup.
- Lei Yang
- , YongMan Choi
- & Meilin Liu
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Imaging oxygen defects and their motion at a manganite surface
Oxygen diffusion processes are critical for the catalytic action of manganites but a full understanding of these processes is elusive. The authors perform atomic resolution scanning tunnelling microscopy imaging of layered manganites and show oxygen and defect dynamics on these surfaces.
- B. Bryant
- , Ch. Renner
- & G. Aeppli
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Enhanced proton transport in nanostructured polymer electrolyte/ionic liquid membranes under water-free conditions
One challenge in the development of proton exchange fuel cells is the requirement for durable, high-conductivity electrolytes. The authors show that incorporating ionic liquids into synthetic block co-polymer electrolytes results in nanostructured membranes with much higher conductivities than currently available.
- Sung Yeon Kim
- , Suhan Kim
- & Moon Jeong Park
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Engineering hybrid nanotube wires for high-power biofuel cells
Miniaturizing fuel cells for biological applications is challenging due to poor performance at these small scales. Now Gao and coworkers show that electrodes made with porous microfibers composed of oriented carbon nanotubes are capable of delivering fast mass transport of the reagents and greatly enhanced currents.
- Feng Gao
- , Lucie Viry
- & Nicolas Mano