Sensitivity and selectivity of Pt electrodes for hydrocarbon sensing in an ultra high vacuum environment

X-ray photoelectron spectroscopy (XPS) and temperature-programmed reaction (TPR) were used to investigate the suitability of polycrystalline platinum as a sensing electrode for sensitive and selective detection of hydrocarbons in a vacuum environment by electrochemical means. At 870 K, all the species investigated undergo precursor-mediated dissociative adsorption to yield graphite, though at widely different rates. It is found that polycrystalline platinum discriminates effectively between “sticky” hydrocarbons such as alkenes, aromatics and alkanes >C5 on the one hand, and “benign” low molecular weight alkanes on the other. The proposed methodology offers a promising way forward with respect to the intended application.