On-line mass spectrometry system for measurements at single-crystal electrodes in hanging meniscus configuration

Abstract

We present the construction and some first applications of an On-line electrochemical mass spectrometry system for detecting volatile products formed during electrochemical reactions at a single-crystal electrode in hanging meniscus configuration. The system is based on a small inlet tip made of porous Teflon and a Peek holder, which is brought in close proximity (ca. 10-20 lm) to the electrode surface. The tip is connected to the mass spectrometer by glass and metal tubing. Because of the small amount of gas entering the mass spectrometer, no differential pumping is needed during the measurement. The tip construction and preparation introduced here leads to reproducible voltammetry with very good cleanliness characteristics. The presence of the tip has no significant influence on the blank voltammetry of a Pt(111) in sulfuric acid, and on voltammetric responses for CO adlayer oxidation, methanol oxidation, and hydroxylamine electrochemistry on Pt(111). The formation of gaseous products in these reactions can be followed accurately and is in good agreement with earlier results obtained by other mass spectrometric or spectroscopic techniques. The time response and tailing of the setup is on the order of seconds and mainly determined by the distance between the tip and the electrode.

CO2 electroreduction on P4VP modified copper deposited gas diffusion layer electrode: pH effect

“…4 show almost no formic acid formation. This difference between HPLC-coupled voltammetry and HPLC-coupled electrolysis indicates that formic acid production is affected by the electrolysis time which maybe due to the possible copper dissolution and complexation with P4VP in the acidic environment [34].…”

“…Online electrochemical mass spectroscopy (OLEMS) and high-performance liquid chromatography (HPLC) were used to detect gas phase and liquid phase products during CO 2 reduction as described previously [27,28,34,35].…”

Activation pathways taking place at molecular copper precatalysts for the oxygen evolution reaction

“…An Ivium A06075 potentiostat was used in combination with the OLEMS experiments. A detailed description of the OLEMS setup is available elsewhere [40].…”

Design, Construction and Research Application of a Differential Electrochemical Mass Spectrometer (DEMS)

“…An alternative approach to positioning the WE close to the membrane interface, is to position a PTFE membrane covered capillary inlet vacuum interface close to WE [50][51][52][53]. The capillary inlet (also known as the pinhole inlet) DEMS technique is illustrated in figure 2-5.…”

“…In order to interface this vacuum system to an electrochemical cell via a microporous PTFE membrane with a total gas flux of 0.09 mbar l s -1 cm -2 then the acceptable membrane interface geometrical area is 0.033 cm -2 . Although a single pumping stage may be sufficient for the capillary inlet DEMS vacuum system [51], such as small membrane surface area is rather impractical for the classic and thin-layer DEMS cells, which employ somewhat higher geometrical areas ~ 1 cm 2 [28,40].…”