An experimental setup for in situ photoelectrochemical measurements of passive films in high-temperature, high-pressure electrolytes are described. The setup enables photovoltammetric and photocurrent spectroscopic measurements at temperatures up to 300 °C and at pressures up to 10 MPa. The first results on the photocurrent response of the passive film on Fe in 0.05 M Na2B4O7 (pH 9.3) are presented. The dependences of the photocurrent on photon energy and electrode potential are explored. The results are discussed in terms of the effect of temperature and potential on the nature of the photoactive layer in the passive film on Fe. It can be concluded that despite the increase in the overall thickness of the film on Fe with increasing temperature, the thickness of the photoactive layer seems to remain constant.
- passive film
- high-temperature aqueous electrolyte
- re-circulation loop