Dicationic poly(4-vinyl pyridinium) ionic liquid capsules as template for Co nanoparticle preparation and H2 production from hydrolysis of NaBH4

•P(4-VP) microgels as colloidal ionic liquid capsule were prepared.•Dicationic p(4-VP) capsules with different anions as counter ions were formed via ion exchange.•P(4-VP) capsules were used as template for metal nanoparticle preparation and as soft reactor.•P(4-VP) capsules containing Co catalyst were used in H2 generation via NaBH4 hydrolysis. Poly(4-vinyl pyridine)-silica (p(4-VP)-silica) composites were synthesized via micro emulsion polymerization, and the capsule of p(4-vinyl pyridine), as cap-p(4-VP), was prepared by removing the core silica from p(4-VP)-silica composites by HF treatment. Dicationic particles in the form of cap-poly(4-vinyl pyridine)++-1,4-butane (cap-p(4-VP)++-C4), capsule-poly(4-vinyl pyridine)++-1,6-hexane (cap-p(4-VP)++-C6), and capsule-poly(4-vinyl pyridine)++-1,8-octane (cap-p(4-VP)++-C8) were prepared by modifying cap-p(4-VP) particles with corresponding dibromo alkanes. Then, polymer–metal composites were also prepared from cap-p(4-VP) and dicationic cap-p(4-VP) particles by loading CoCl2 from ethanol and the obtained composites were used in H2 generation from hydrolysis of NaBH4, and The Ea for the composite catalyst was calculated as 56.53kJ/mol.