Reaction synthesis of TiSi₂ and Ti₅Si₃ by ball-milling and shock loading and their photocatalytic activities

Shock loading and high energy ball-milling are typical mechanochemical processing methods by which the chemical reaction of different substances can be initiated and the functional materials with particular physical and chemical properties were produced. In this paper, the precursors of Ti-Si powder with different stoichiometric ratios were pre-activated by ball-milling and then loaded by shock wave. The recovered samples were characterized by XRD, SEM, and DSC, and photocatalytic activity of splitting water into hydrogen was evaluated under visible light. The results indicate that shock-induced reaction of Ti-Si is easier after certainly ball-milling treatment in which the Ti ₅Si₃ with high thermodynamic stability was produced in the precursor mixtures of Ti:Si = 1:2 and the designed Ti₅Si₃ was also produced in that of Ti:Si = 5:3. The test for photocatalytic activity shows that there has a common sequence of photocatalytic activity of the treated samples with different stoichiometric ratios including the precursor mixtures of Ti:Si = 1:2 and 5:3: (ball-milling + shock loading) > shock loading > ball-milling meaning that the samples treated by both of milling and shock loading exhibit better photocatalytic activity than that of only milling or shock loading due to the greater degree of activation.