Co–P–B catalyst thin films prepared by electroless and pulsed laser deposition for hydrogen generation by hydrolysis of alkaline sodium borohydride: A comparison

Co–P–B catalyst thin films have been synthesized on Ni-foam and glass substrate by using electroless deposition (ED) and pulsed laser deposition (PLD) respectively. The efficiency of these catalyst films was tested by catalytic hydrolysis of NaBH4 for H2 generation. While the chemically produced Co–P–B film on Ni-foam shows similar activity as that of their corresponding powder, the Co–P–B film deposited by PLD exhibits much superior H2 generation rate as compared to Co–P–B powder. We attribute this increased efficiency to the special features of the Co–P–B films which are in the form of nanoparticle-assembled films, a peculiar characteristic of PLD films for appropriate choice of the pulse laser parameters. The surface nanoparticle-configuration increases the active surface area and also favors electronic exchange mechanisms to promote hydrolysis process for H2 gas generation. The films deposited by using laser energy density of 3 J/cm2 show the highest activity in connection to the best configuration of the ablated nanoparticles. Different numbers of Co–P–B layers were deposited on Ni-foam by ED and it was found that at least four layers are required for complete coverage of the foam to have the best activity.