Development and reactive oxygen-species scavenging activity of a new chemical hydrogen-generating system, CaMg2-hydroxypropyl cellulose-citric acid, prepared using Laves-phase CaMg2 and its relationship to chemical hardness

Abstract

We developed a new chemical hydrogen-generating CaMg₂-hydroxypropyl cellulose-citric acid (CAMGCC) system from Laves-phase CaMg₂ by using an arc melting method. The CAMGCC generated hydrogen gas (H₂) rapidly for 2–3 min on the addition of water. Moreover, the CAMGCC system could scavenge reactive oxygen species (ROS), such as toxic hydroxyl radicals (˙OH) and superoxides (O₂⁻˙) effectively. To develop a new chemical hydrogen-generating system that generates H₂ efficiently, it is essential to calculate the quantity (ΔQ) of electron transfer from metal and alloy to H₂O by using the absolute hardness (η) and absolute electronegativity (χ) based on chemical hardness. Metals and alloys with a large amount of calculated ΔQ can be used as excellent materials to develop a chemical hydrogen-generating system. A larger ΔQ of electron transfer from the metal to H₂O results in a greater antioxidant activity of the system. The results were supported by using the calculation results for clusters of CaMg₂ and Mg₃, instead of crystalline CaMg₂ and Mg. These studies are important in the development of chemical hydrogen-generating systems and antioxidants.