The stability of different types of platinum surfaces in the presence of chloride was evaluated by applying a potential of 1.2 V vs reversible hydrogen electrode while the associated mass change in the Pt electrode was monitored with an electrochemical quartz crystal microbalance. The platinum metal surfaces based on the particles and films show a large difference toward dissolution when exposed to small amounts of chloride. While an electrodeposited platinum metal film showed no degradation in a sulfuric acid solution containing 10 ppm of chloride, an electrode made from a fuel cell catalyst (50 wt % Pt/C) lost 10% of its platinum content over a 24 h period when exposed to a sulfuric acid solution containing 10 ppm of chloride. At a chloride concentration of 20 ppm, the onset potential of the Pt oxide formation increased
∼200mV
compared to an electrode in a chloride-free solution. The degradation of nanoparticles thus appears to be much more significant than for the electrodeposited platinum electrodes.
Two non-electrified railway lines, one in Norway and the other in the USA, are analysed for their potential to be electrified with overhead line equipment, batteries, hydrogen or hydrogen-battery hybrid powertrains. The energy requirements are established with single-train simulations, including the altitude profiles of the lines, air and rolling resistances, and locomotive tractive-effort curves. The composition of the freight trains, in terms of the number of locomotives, battery wagons, hydrogen wagons, etc. is also calculated by the same model. The different technologies are compared by the criteria of equivalent annual costs, benefit–cost ratio, payback period and up-front investment, based on the estimated techno-economic parameters for years 2020, 2030 and 2050. The results indicate the potential of batteries and fuel cells to replace diesel on rail lines with low traffic volumes.
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