Electrochemistry at High Pressures: A Review

Abstract

High pressure electrochemical studies are potentially dangerous and less immediately implemented than conventional investigations. Technical obstacles related to properties of the working electrode material, preparation of its surface, availability of suitable reference electrodes, and the need for specially designed high pressure equipment and cells may account for the relative lack of experimental data on electrochemistry at high pressures. However, despite the stringent requirements for system and equipment stability, significant developments have been made in recent years and the combination of electrochemical methods with high hydrostatic pressure has provided useful insights into the thermodynamics, kinetics, and other physico-chemical characteristics of a wide range of redox reactions. In addition to fundamental information, high pressure electrochemistry has also lead to a better understanding of a variety of processes under non-classical conditions with potential applications in today×s industrial environment from extraction and electrosynthesis in supercritical fluids to measurement of the pH at the bottom of the ocean. The purpose of this article is to detail the experimental pressurizing apparatus for electroanalytical measurements at high pressures and to review the relevant literature on the effect of pressure on electrode processes and on the properties of aqueous electrolyte solutions.

Optical Seeing at Sierra Negra

“…In contrast to the results of Giovanelli et al (2001) for highaltitude cordillera sites in Chile, the data for Sierra Negra suggest that, for our statistics, there is no difference between the 10 and 20 ms series. It must be noted that Vernin & Muñoz-Tuñon (1995) find the seeing bias produced by the difference in exposure time to be highly dependent on the magnitude of the star.…”

“…Muñoz-Tuñon, Vernin, & Varela (1997) observed that there is no general trend in the seeing evolution for the Roque de los Muchachos Observatory. In contrast, Giovanelli et al (2001) point out that for high-altitude cordillera sites in northern Chile, the seeing tends to be of lower quality at the beginning of the evening.…”

“…Giovanelli et al (2001) measure the seeing by alternating 10 and 20 ms exposures for high-altitude cordillera sites in Chile. They obtain seeing estimates derived from 10 ms exposures, 20 ms exposures, and extrapolations to "zero exposure," obtained by multiplying the 10 ms seeing by the ratio of the 10 and 20 ms measurements.…”

Kinetics of Ferric Ion Reduction on Chalcopyrite and its Influence on Leaching up to 150 °C

“…Despite significant effort in the past several decades devoted to the identification of the key parameters that limit the leaching kinetics, except for very few reported results [25,66,67], the majority are limited to temperatures below 90 • C. According to recent reviews of high temperature and high pressure (HTHP) electrochemical studies [68,69], HTHP electrochemistry remains a relatively unexplored field of research and the relative lack of experimental data is ascribed to the various technical obstacles, although in recent years significant developments have been made. As to HTHP mineral electrochemistry, very few reports are available [70].…”

The large Atacama submillimeter telescope

“…Figure 2 shows the location in South America and a topographic image of the Chajnantor Plateau. Site survey work has shown that the precipitable water vapor content is low (typically less than 800 µm and < 200 µm ~25% of the time for the high peaks) 1,2 . Figures 3 shows results from radiosonde measurements from survey campaigns in the latter half of 1998.…”