caa a22 4500 477051022 CHVBK 20180405111340.0 cr unu---uuuuu 170330e19960801xx s 000 0 eng 10.1007/BF00683742 doi (NATIONALLICENCE)springer-10.1007/BF00683742 Arsenic poisoning effects on cathodic polarization and hydrogen adsorption at platinum and steel electrodes in KF · 2HF melts [Elektronische Daten] [L. Gao, S. Qian, B. Conway] It is demonstrated how the presence of arsenic species in the KF · 2HF melt employed as the electrolyte in fluorine production cells greatly affects the electrocatalytic behaviour of the steel electrodes that are used as cathodes. Effects of the introduction of As2O3, AsF3 and AsF5 as the sources of catalyst poison species have been studied. Such species influence the electrode kinetics of the cathodic hydrogen evolution reaction (h.e.r.) and the adsorption of the overpotential-deposited (o.p.d.) H intermediate. Using Pt, as a model electrocatalyst surface, these effects were quantitatively studied by means of potential-relaxation transients, Tafel relations and cyclic voltammetry, the latter enabling changes of underpotential-deposited C (u.p.d.) H coverage due to the presence of As species to be evaluated. By means of simulation of the potential-relaxation behaviour, information on rate constants, coverages by o.p.d. H and As species were also derived. The presence of As at Pt cathodes suppresses the u.p.d. H adsorption and modifies the o.p.d. H behaviour and the associated pseudocapacitance. The presence and generation of As(−iii) species, as AsH3, in the evolved hydrogen gas was demonstrated by means of Marsh's test. The contact-angles of hydrogen bubbles generated in the h.e.r. at mild-steel electrode surfaces were also determined comparatively in relation to observed sluggish hydrogen bubble detachment from the electrode surfaces when As species were present.Ex situ XPS analysis confirmed the presence of As species on the electrode surface. Chapman & Hall, 1996 Gao L. Department of Chemistry, University of Ottawa, 10 Marie Curie Street, KIN 6N5, Ottawa, Canada aut Qian S. Department of Chemistry, University of Ottawa, 10 Marie Curie Street, KIN 6N5, Ottawa, Canada aut Conway B. Department of Chemistry, University of Ottawa, 10 Marie Curie Street, KIN 6N5, Ottawa, Canada aut Journal of Applied Electrochemistry Kluwer Academic Publishers 26/8(1996-08-01), 803-814 0021-891X 26:8<803 1996 26 10800 https://doi.org/10.1007/BF00683742 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00683742 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Gao L. Department of Chemistry, University of Ottawa, 10 Marie Curie Street, KIN 6N5, Ottawa, Canada aut NATIONALLICENCE 700 1- Qian S. Department of Chemistry, University of Ottawa, 10 Marie Curie Street, KIN 6N5, Ottawa, Canada aut NATIONALLICENCE 700 1- Conway B. Department of Chemistry, University of Ottawa, 10 Marie Curie Street, KIN 6N5, Ottawa, Canada aut NATIONALLICENCE 773 0- Journal of Applied Electrochemistry Kluwer Academic Publishers 26/8(1996-08-01), 803-814 0021-891X 26:8<803 1996 26 10800 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer