Hydrogen production from NaBH4 hydrolysis via Co-ZIF-9 catalyst

ZIF-9, one of the zeolitic imidazolate frameworks, was synthesized via solvothermal method and the feasibility of ZIF-9 as catalyst in NaBH4 hydrolysis for hydrogen production was firstly reported in detail. The experimental result showed that initial hydrogen generation rate of ZIF-9 catalyst is relatively slow due to the gradual formation of CoB active centers. And then the hydrogen generation rate increases rapidly after the formation of CoB. The hydrogen generation rate of ZIF-9 at 40 °C can reach up to 3641.69 ml min− 1 g− 1(Co). It was found that the addition of NaOH can remarkably accelerate the hydrolysis rate of NaBH4. In the cycles of ZIF-9, no obvious decrease of hydrogen production rate was found which meant that ZIF-9 catalyst maintains relatively high stability. The XRD comparison before and after the cycling reaction showed that ZIF-9 maintains its basic crystal structure and crystallinity, but long range order of ZIF-9 catalyst is altered in a certain extent.

► Co-ZIF-9 catalyst was synthesized via solvothermal method.
► ZIF-9 catalyst was used in NaBH4 hydrolysis for hydrogen production.
► There remains an initial induction period due to the gradual formation of CoB.
► The increase of NaOH can shorten the induction period of CoB formation.
► The catalyst shows good stability in the studied temperature range.