When dropping mercury electrode (DME) dipped in ultrapure water, thoroughly deaerated with pure hydrogen, is irradiated with UV light, we can observe a cathodic photocurrent in the non-faradaic region of the polarographic curve, in the absence of scavengers of hydrated electrons. Newly we have followed the effect on photocurrent of initial very small additions of alkali metal chlorides to pure water. By repeated experiments, we could show that first additions of the alkali metal halides increase the photocurrent and that the already known suppression of photocurrent by addition of halides begins only after the halide concentration exceeds ca 10-4 mol 1-1. We could show for the first time that in ultrapure water and dilute electrolyte solutions, the photocurrent follows a modified seven-halves law. The extent of the positive effect of small additions of alkali metal halides on photocurrent depends on the nature of each alkali metal cation. The reason for this specificity is discussed.

Effect of alkali halides upon photocurrent due to emission of electrons from dropping mercury electrode into water

PASSAMONTI, Paolo;PUCCIARELLI, Filippo
2002-01-01

Abstract

When dropping mercury electrode (DME) dipped in ultrapure water, thoroughly deaerated with pure hydrogen, is irradiated with UV light, we can observe a cathodic photocurrent in the non-faradaic region of the polarographic curve, in the absence of scavengers of hydrated electrons. Newly we have followed the effect on photocurrent of initial very small additions of alkali metal chlorides to pure water. By repeated experiments, we could show that first additions of the alkali metal halides increase the photocurrent and that the already known suppression of photocurrent by addition of halides begins only after the halide concentration exceeds ca 10-4 mol 1-1. We could show for the first time that in ultrapure water and dilute electrolyte solutions, the photocurrent follows a modified seven-halves law. The extent of the positive effect of small additions of alkali metal halides on photocurrent depends on the nature of each alkali metal cation. The reason for this specificity is discussed.
2002
262
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11581/114905
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact