Hydrogen generation via hydrolysis of Si/CaH2 composite: performance evaluation and application

Si-based hydrolysis hydrogen production is considered a promising green hydrogen generation technology due to its ability to rapidly release hydrogen under ambient temperature and pressure, with non-toxic and pollution-free reaction products. However, the intrinsic chemical inertness of silicon and the rapid formation of a dense SiO₂ passivation layer on its surface in aqueous environments severely hinder its reaction with water, thereby limiting the hydrolysis reaction rate and hydrogen production efficiency. In this work, waste silicon powder was mixed with calcium hydride (CaH₂) via ball milling to prepare Si/CaH₂ composite materials. The key factors influencing their hydrolysis performance were investigated by varying the ball milling time and hydrolysis conditions. The Si/CaH₂@15h sample exhibited a high hydrogen yield of 1049 mL/g and an impressive hydrogen generation efficiency of 91.06 % when hydrolyzed in 0.5 M NaF solution. This composite material also demonstrated excellent hydrogen generation performance in fuel cell testing, achieving effective hydrogen-to-electricity conversion. This study provides a new approach for Si-based hydrolysis hydrogen production and photovoltaic resource recycling, offering a scalable method for fuel cell applications.