Co-CeOx nanoparticles anchored on a nitrogen-doped carbon nanosheet: a synergistic effect for highly efficient hydrolysis of sodium borohydride

Hydrolytic dehydrogenation of sodium borohydride (NaBH4) has been considered as a source of hydrogen for fuel cell applications. In this work, amorphous and electron-rich Co-CeOx nanoparticles (NPs) with a small size of 4.4 nm anchored on a nitrogen-doped carbon nanosheet (NCNS) have been prepared via a simple and facile chemical reduction method, in which NCNS was obtained by carbonizing a mixture of metal-organic frameworks ZIF-8 and potassium citrate. The as-prepared Co-CeOx/NCNS catalyst possesses an outstanding catalytic activity for the catalytic hydrolysis of NaBH4 at room temperature under alkaline conditions, giving a hydrogen generation rate (HGR) value as high as 28 410 mL(H2)center dot min(-1)center dot g(Co)(-1), which is among the highest HGR values reported to date for all catalysts. The kinetics of hydrolytic dehydrogenation of NaBH4 aqueous solution was investigated in detail. The excellent catalytic activity of Co-CeOx/NCNS can be owing to the small size and amorphous state of Co-CeOx NPs, electron-rich properties of Co NPs modulated by the CeOx promoter, strong synergistic interaction between Co-CeOx NPs and the NCNS support with a high surface area and abundant defects, and the promotion of NaOH.

Automated summary

In this study, Co-CeOx/NCNS catalyst with outstanding catalytic activity for the hydrolytic dehydrogenation of NaBH4 was successfully prepared, achieving a high hydrogen generation rate. The superior performance can be attributed to the synergistic effects of various factors, such as the special properties of nanoparticles, the influence of support surface area and defects, among others.