The ionic activity at the interfaces of the membrane and the ionic polymer phase in the catalyst layers can have a significant impact on the transport rates of protons and water in a proton exchange membrane fuel cell ͑PEMFC͒. This study investigated the effects of some treatment processes on the surface ionic activity of extruded Nafion membranes and their performance in a PEMFC. The treatment processes included H 2 SO 4 and H 2 O 2 wash and plasma sputter and reactive ion etching. The membrane surface ionic activity was determined by the S:C ratio using X-ray photoelectron spectroscopy. The results showed that the surface of these membranes, as received and after H 2 SO 4 wash, had lower ionic activity than that of its bulk ͑S:C = 0.026 vs 0.053͒. Treatment with H 2 O 2 had a significant impact on the surface ionic activity, lowering the surface S:C ratio further to 0.017. The Teflon-rich skin of extruded Nafion membranes could be removed by sputter etching with argon exposing a surface with higher ionic activity ͑S:C = 0.047͒. However, reactive ion etching with SF 6 and argon led to a further decrease in the surface ionic activity ͑S:C = 0.011͒. Fuel cell results showed a strong correlation between the membrane surface ionic activity and the fuel cell performance.

Due to the high economic, environmental, and safety costs associated with pure oxygen, mixedconducting oxygen-permeable ceramic membranes are being explored as an alternative oxygen source for hydrocarbon conversion reactors. This work reports a dramatic improvement in catalyst performance when an oxygen-permeable SrFeCo 0.5 O x ceramic membrane is used in conjunction with a conventional powder Pt/ZrO 2 catalyst for the CO 2 reforming of CH 4 . Experiments comparing catalyst performance with up to 2% co-fed oxygen to catalyst performance with oxygen from the ceramic membrane demonstrated a conversion three times higher with the membrane than with any amount of co-fed oxygen. The results suggest that membrane oxygen is more beneficial for catalyst activity and stability than molecular gas-phase oxygen.

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A dramatic increase in the GaAs etch rate has been observed with the addition of SF 6 to BCl 3 plasmas. The etch rate increases from 70 Å/min in pure BCl 3 to 4000 Å/min with 70% SF 6 in the total flow. Optical emission intensities of both molecular and atomic chlorine were observed to increase with SF 6 addition, and the peak intensity of the atomic chlorine emission coincided with the peak in the etch rate. Argon was added to the mixture as an actinometer, and the argon emission intensity at 750 nm increased significantly with the addition of SF 6 . However, microwave measurements indicated that the average electron density decreases with increasing SF 6 addition. It is believed that the increased production of etch species is due to an increase in the average electron temperature as a result of electron attachment heating.

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