Electrodeposited Co–Zn on Ni foam as efficient catalysts for hydrogen generation from hydrolysis of sodium borohydride

Abstract

For hydrogen generation based on the sodium borohydride hydrolysis, the development and application of efficient catalysts are of key importance. In this work, Co and Co–Zn catalysts were prepared on Ni foam by electrodeposition process. Field-emission scanning electron microscopy (FE-SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were employed for materials characterization, and catalyst performance was measured by typical water-displacement method. Experimental results indicate that the doping of zinc affects the morphology and microstructure of catalyst and promotes the effective catalytic area, leading to higher hydrogen generation rate (HGR) by comparing with Co/Ni. Furthermore, HGR can be further improved by treating the Co–Zn/Ni with NaOH solution because the partial dissolving of zinc results in the increase of cobalt active sites. Using a 10[Formula: see text]wt.% NaBH4 and 5[Formula: see text]wt.% NaOH solution, the HGR was as high as 455[Formula: see text]mL min[Formula: see text] g[Formula: see text] at 25[Formula: see text]C, and the apparent activation energy was measured to be 50.2[Formula: see text]kJ mol[Formula: see text]. Cyclic performance of the NaOH-treated Co–Zn/Ni was investigated as well.