Supplementary Information Photolithography ProcedureMetal patterns were fabricated by metal liftoff photolithography. Positive photoresist (Shipley 1813) was spin-coated onto YSZ substrates at 2,000 to 3,000 rpm and baked at 115 °C for 150 s. The sample was then aligned with the glass plate mask using a Karl Suss MJB 3 contact aligner and exposed to UV

Through the use of ambient pressure X-ray photoelectron spectroscopy (APXPS) and a single-sided solid oxide electrochemical cell (SOC), we have studied the mechanism of electrocatalytic splitting of water (H 2 O + 2e − → H 2 + O 2− ) and electro-oxidation of hydrogen (H 2 + O 2− → H 2 O + 2e − ) at ∼700°C in 0.5 Torr of H 2 /H 2 O on ceria (CeO 2−x ) electrodes. The experiments reveal a transient buildup of surface intermediates (OH − and Ce 3+ ) and show the separation of charge at the gas−solid interface exclusively in the electrochemically active region of the SOC. During water electrolysis on ceria, the increase in surface potentials of the adsorbed OH − and incorporated O 2− differ by 0.25 eV in the active regions. For hydrogen electro-oxidation on ceria, the surface concentrations of OH − and O 2− shift significantly from their equilibrium values. These data suggest that the same charge transfer step (H 2 O + Ce 3+ ⇔ Ce 4+ + OH − + H • ) is rate limiting in both the forward (water electrolysis) and reverse (H 2 electrooxidation) reactions. This separation of potentials reflects an induced surface dipole layer on the ceria surface and represents the effective electrochemical double layer at a gas−solid interface. The in situ XPS data and DFT calculations show that the chemical origin of the OH − /O 2− potential separation resides in the reduced polarization of the Ce−OH bond due to the increase of Ce 3+ on the electrode surface. These results provide a graphical illustration of the electrochemically driven surface charge transfer processes under relevant and nonultrahigh vacuum conditions. ■ INTRODUCTIONUnderstanding the mechanisms of charge separation and charge transfer at electrochemical interfaces is essential for the rational development of electrochemical devices, such as batteries, fuel cells, electrolyzers, and supercapacitors. 1,2 However, the materials and operating conditions employed in real world applications of these technologies are usually quite different from those used in surface science studies on model systems (i.e., the "pressure and materials gap"). 3−5 This disconnect is particularly problematic with high temperature electrochemical energy conversion devices with multicomponent materials (e.g., solid oxide fuel cells, electrolyzers, and electrocatalytic fuel processors) 6 for which in situ surface experiments at cell operating temperatures (typically >500°C) are challenging. 7 Because of the experimental constraints of most surface science experiments, the knowledge and understanding of the surface processes at relevant conditions are limited and rely on extrapolations from ultrahigh vacuum (UHV) conditions and modeling studies. 8 As a result, the electrochemical surface processes are not well understood. For example, the nonFaradaic electrochemical modification of catalytic activity (NEMCA or EPOC) 9 can significantly enhance the rates of catalytic transformation of over 100 reactions, 3,10 yet the origins of this enhancement are not fully understood. 3 Even the mechanism ...

A pot experiment was conducted to evaluate the role of glycinebetaine (GB) in Cr tolerance in mung bean (Vigna radiata L.) grown in soil. Three concentrations of Cr (0, 250 and 500 µM) were tested with three (0, 50 and 100 mM) concentrations of foliar applied GB. Chromium alone led to a significant decrease in plant growth, biomass, contents of chlorophyll a, b and carotenoids concentrations. Chromium concentration and electrolyte leakage significantly increased in plants with increasing Cr levels in the soil. Lower Cr stress enhanced the activities Downloaded by [RMIT University] at

We study the interplay between competitive substrate-C interaction processes occurring during chemical vapour deposition (CVD) of ethylene on Re(0001). At T < 500 K dissociative ethylene adsorption leads to the formation of a dimer species, producing an ordered (4 × 2) structure. In the range 500 − 700 K, the formation of a high-quality single-layer of graphene (GR) is strongly opposed by the formation of a surface carbide characterised by C trimer units, and, at higher temperatures, by carbon dissolution into the bulk. Our experimental and theoretical results demonstrate that, under UHV conditions, the formation of a long-range ordered GR layer on * Corresponding author. Tel.(+39)040 375-8719. E-mail:alessandro.baraldi@elettra.eu Preprint submitted to CarbonDecember 12, 2013Re(0001) without carbon bulk saturation is confined to a narrow window of growth parameters: substrate temperature, hydrocarbon gas pressure and exposure time. Our combined experimental and theoretical approach allowed us to validate a concept which had already been anticipated in some earlier works on Rh,Fe and Ni, namely that the epitaxial growth of GR is not necessarily restricted to surfaces where carburisation is precluded, but could take place, under given appropriate conditions, also on other metallic substrates exhibiting a strong C-substrate interaction.

Metal organic–frameworks (MOFs) with intriguing structural motifs and unique properties are potential candidates for carbon dioxide (CO2) storage.

The CoO film deposited on the surface of F-doped SnO2 (FTO) conductive glass was prepared via drop casting technique. The effects of Ni2+-ion implantation at 700 keV energy and postannealing in vacuum at 450 °C temperature on the local structure of the CoO film was systematically explored. The XAFS study revealed the substitution of octahedral Co2+ by Ni2+ ion (Co1–x Ni x O) as a result of ion implantation. The existence of defects in local structure around the octahedral Co for the Co1–x Ni x O film after thermal annealing in vacuum was demonstrated by the theoretical EXAFS [χ­(k)] simulation via evolutionary algorithm implemented in reverse Monte Carlo method in rationale with EXAFS fitting. Nevertheless, the cubic rock salt structure for the Co1–x Ni x O was conserved, corroborated through XRD patterns, suggesting a remarkable candidate for application as an electrocatalyst in fuel cells.

Substoichiometric tungsten oxide films of approximately 10 nm thickness deposited with pulsed laser ablation on single-crystal TiO 2 substrates with (001) and (110) orientation show defect states near the Fermi energy in the valence-band X-ray photoelectron spectroscopy (XPS) spectra. The spectral weight of the defect states is particularly strong for the film grown on the (001) surface. In situ XPS under an oxygen pressure of 100 mTorr shows that the spectral weight of the defect states decreases significantly at 500 K for the film on the (110) substrate, whereas that of the film grown on the (001) substrate remains the same at a temperature up to 673 K. Furthermore, diffusion of titanium from the substrate to the film surface is observed on the (110) substrate, as is evidenced by the sudden appearance of the Ti 2p core level signature above 623 K and below 673 K. The film grown on the (001) surface does not show such an interdiffusion effect, which suggests that the orientation of the substrate can have a significant influence on the high-temperature integrity of the tungsten oxide films. Quantitative analysis of the O 1s core level XPS spectra shows that chemisorbed water from sample storage under ambient conditions is desorbed during heating under oxygen exposure.

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