In-situ synthesis of porous silica-ruthenium composite catalyst for hydrolysis of ammonia borane

The present study reports in-situ synthesis of porous silica-ruthenium composite catalyst for hydrolysis of ammonia borane. The in-situ synthesized catalyst precursors were prepared via sol-gel based methods using surfactant micelles of cethyltrimethylammonium bromide (CTAB) to form well-ordered nanopores in the precursor particles. The precursors consisted of spherical particles with the diameter of ca. 20-60 nm and nanopores with the diameter of ca. 2-3 nm were included in the precursor particles. The specific surface areas and pore volumes decreased with increasing of ruthenium content, while their catalytic activity for hydrogen generation from aqueous ammonia borane solution was the same level regardless of the ruthenium contents. The catalytic activity was effectively improved via reflux procedure of the precursors through removing residual compound probably originated from CTAB with maintaining dispersion of the active ruthenium species after the procedure.