Prussian blue analogues as heterogeneous catalysts for hydrogen generation from hydrolysis of sodium borohydride: a comparative study

As a special class of coordinated frameworks comprised of various metal species, Prussian blue analogues (PBAs) have received increasing attention for catalytic applications. Nevertheless, few studies have been performed to investigate catalytic activities of PBAs for hydrogen generation (HG) from NaBH(4)hydrolysis. No researches have been implemented to examine effects of different M(II)and M(III)of PBAs (M-3(II)[M-III(CN)(6)](2)) (M-II = Co, Fe, Mn, Ni, and Zn; M-III = Fe, Co) on NaBH(4)hydrolysis for HG. Thus, the aim of the study is to explore and compare catalytic activities of various PBAs for HG from NaBH(4)hydrolysis. While two hexacyano-metalates and different metals are used to obtain various PBAs, Co-3[Co(CN6)](2)(Co-Co) is the most effective PBA for HG from NaBH(4)hydrolysis. Furthermore, Co-Co has a much lowerE(a)of 37.6 kJ/mol for HG from NaBH(4)hydrolysis in comparison toE(a)values by other reported catalysts. Besides, HG by Co-Co could be optimized in the presence of 5% NaOH concentration, which leads to an even lowerE(a)of 28.6 kJ/mol. Co-Co is also reusable and stable for multiple cycles of HG. These features reveal that Co-containing PBAs can be a promising heterogeneous catalyst to facilitate HG from NaBH(4)hydrolysis.