• We developed both pH and Cl- imaging plates, which can visualize the pH and Cl- concentration on metal surfaces in acidic environments. The pH range is from 3.0 to 0.5, and Cl- concentration up to 4 M can be measured. Fluorescent dyes are successively used for pH and Cl- imaging in the field of biology, but their sensitivity tends to be insufficient in acidic and/or highly concentrated chloride solutions. A glass plate with a sol-gel sensing layer, which contains a pH indicator or a Cl- sensitive florescent dye was fabricated and validated using the solutions with various pH values and Cl- concentrations. Changes in the pH and Cl- distribution on stainless surface in an acidic environment were measured quantitatively.

The newly developed imaging plates can be used to investigate the mechanism of various chemical reactions, such as corrosion, which occurs in an acidic environment. Micro-flow imaging using our sensing technique will be a promising approach to understand the catalytic chemistry of metal surfaces.
強調

• Chemical imaging
• Solution chemistry
• Electrochemistry
• Corrosion
• Crevice corrosion
• Thin-film type sensor