Influence of M–B (M = Fe, Co, Ni) on aluminum–water reaction

Abstract

In this work, the aluminum–water reaction induced by Fe–B, Co–B and Ni–B particles was studied. The catalysts were mixtures of the metal boride and metallic particles. The chainlike Fe–B catalyst forms a network structure under the influence of an external magnetic field and has a large specific surface area. Aggregated particles of Co–B and Ni–B catalyst have small specific surface area. Catalytic activity in the initial corrosion of aluminum increases with increasing Fe–B content because of the large specific surface area and the formation of a micro galvanic cell. However, the amount of hydrogen generated slowly decreases with increasing amount of Co–B and Ni–B. The activity of Fe–B, Co–B and Ni–B in the initial Al/H2O reaction decreases in the order Fe–B > Ni–B > Co–B. The calculated apparent activation energies in the presence of Fe–B, Co–B and Ni catalysts are 38.2, 39 and 29.6 kJ mol−1, respectively. Aluminum is rapidly and completely corroded in a weakly alkaline solution (pH < 10) after consecutive additions of Al batches because of high concentrations of OH− in the local domain and an increase in the amount of Al(OH)3 precipitate.