Effect of bath composition on properties of electroless deposited Co-P/Ni foam catalyst for hydrolysis of sodium borohydride solution

摘要

The effect of bath composition on the properties of electroless deposited Co-P/Ni foam catalyst for hydrolysis of sodium borohydride solution was investigated by varying the bath composition. The NaH_2PO_2/CoCl_2 and NH_2CH_2COOH/CoCl_2 concentration ratio had a strong effect on the catalyst properties. The effect of NH_2CH_2COOH/CoCl_2 was larger than that of NaH_2PO_2/ CoCl_2 for the concentration ratio range with practical deposition rates. The optimum concentration ratio of the coating bath was CoCl_2:NH_2CH_2COOH:NaH_2PO_2 = 1:4:10. As the concentration of each component increased at the optimum concentration ratio, the coating bath decomposed on its own. As the amount of solute dissolved in the coating bath increased, the coating bath became unstable. The optimum composition of the stable coating bath to realize Co-P/Ni foam catalyst with good catalytic activity was 0.1 m (molality, mol/kg) CoCl_2, 0.4 m NH_2CH_2COOH, and 1.0 m NaH_2PO_2. The weight percent of the deposited catalyst and hydrogen generation rate per deposited catalyst of 1 g at optimum composition were 8.39 wt% and 0.93 L/ming (deposited catalyst), respectively. The bath composition was found to have a great effect on the Co-P/Ni foam catalyst properties and coating bath stability.