Crystalline Formation Enhances Hydrogen Evolution Reaction Property of Copper Azaphthalocyanine on Carbon Electrodes

Alkaline water electrolysis and alkaline exchange membrane (AEM) water electrolysis are expected to be next-generation hydrogen generation devices due to their low corrosion, high efficiency, and low maintenance costs. The performance of the electrode catalyst is especially important as it directly affects the overvoltage of water electrolysis, and platinum (Pt), a rare metal, has traditionally been used as a catalyst for the hydrogen evolution reaction (HER) due to its direct impact on the overvoltage of hydrogen generation. However, due to resource constraints and rising costs, the development of alternative catalysts is underway. In this study, the formation of copper azaphthalocyanine (CuAzPc-4N) was directly coated on a carbon electrode as a HER catalyst. X-ray analysis and microscopic measurements revealed crystalline formation at high loading conditions. Scanning electrochemical cell microscopy showed that morphological differences were found in the samples with alternating coating times, and the crystal of CuAzPc-4N exhibits higher HER activity than its molecular state.