Study on the photogenerted cathodic protection of Ti-P-V-O coating photoelectrode prepared by microarc oxidation method for 304 stainless steel

Abstract

Photocathodic protection is a promotion strategy for the corrosion protection of metallic materials, and the selection of photocathodic materials is a critical factor in improving the performance of photocathodic protection of metallic materials. Herein, a Ti-P-V-O composite semiconductor photoelectrode with an adjustable porous structure was prepared by the micro-arc oxidation (MAO) method using titanium alloy (TC4) as the matrix and ammonium metavanadate (NH4VO3) as the additive. The photogenerated open circuit potential, instantaneous photocurrent density response value, electrochemical impedance spectroscopy, and Tafel curve of as-prepared Ti-P-V-O photo-electrodes were measured after coupling with 304SS to clarify the cathodic protection effect for 304 stainless steel (304SS). It is found that the as-prepared Ti-P-V-O coating photoelectrode has a more negative open circuit potential, a more significant photocurrent density response, more effective interface carrier transport ability, lower resistance, lower compounding efficiency of photogenerated electron/hole pairs, and more negative conduction band level, as compared with that of TiO2 coatings. Moreover, the optimized Ti-P-V-O photoelectrode (Ti-P-V-O&300 V) exhibited the maximum negative shift of the corrosion potential (410 mV vs. SCE) for coupling with 304 stainless steel. This work presents a new strategy for constructing an efficient coating photo-electrode for photocathodic protection of metallic materials.