Styrene oxide undergoes an activated ring opening on Ag(111) at temperatures above 200 K. The product of this reaction is a stable oxametallacycle intermediate. The structure of this species has been obtained by density functional theory calculations and the computed vibrational spectrum is consistent with the experimental spectrum obtained using high-resolution electron energy loss spectroscopy. The oxametallacycle formed by ring-opening styrene oxide is structurally analogous to that previously observed for ring opening of epoxybutene on Ag(110) and represents the largest member of this adsorbate structure class yet isolated. In both cases, the epoxide ring opens at the carbon bearing the pendant unsaturated group, and the pendant group (phenyl in styrene oxide) is oriented nearly parallel to the surface plane. The oxametallacycle formed from styrene oxide reacts at 485 K to regenerate styrene oxide plus small amounts of phenylacetaldehyde. This peak temperature is similar to that previously reported for generation of styrene oxide from adsorbed styrene and oxygen atoms on Ag(111), suggesting that the epoxidation proceeds via the oxametallacycle intermediate isolated in the present work.

The adsorption of arsine by copper−palladium alloys was studied using a high-throughput composition spread alloy film (CSAF) sample library. A Cu x Pd 1−x CSAF coupon that spanned the complete alloy composition space (x = 0−1) was prepared by an evaporative deposition technique. The coupon was exposed to AsH 3 in a N 2 background at 288 °C in a small flow reactor. Arsenic uptake was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy (SEM-EDX), and micro X-ray diffraction (μ-XRD). Pd-and Cu-rich alloy compositions exhibited large surface concentrations of As after exposure to AsH 3 . In the Cu-rich alloy, composition and structure measurements suggest the formation of a Cu 3 As phase. Arsenic uptake at Pd-rich alloy compositions is consistent with Pd 2 As or Pd 8 As 3 phases; structural results suggest Pd 2 As with a hexagonal structure. In contrast, over a wide range of intermediate compositions (x Cu ≈ 0.20−0.75), little As uptake was observed. These results contribute to a basis for rational design of sorbents for the capture of arsenic from fluid streams, and to an understanding of the stability of palladium−copper alloy membranes employed for hydrogen separation from coal-derived syngas. This work illustrates the application of high-throughput approaches based on CSAF sample libraries that can be applied to a wide variety of materials development and optimization challenges.