Research on hydrogen generation rate and corrosion resistance of Ni-P catalyst in NaBH₄ fuel cell

Scaly structured Ni-P catalyst were prepared on copper sheet surface by electroless plating for hydrogen evolution from NaBH₄ seawater solution. The result shows that with the increasing of Ni-P proportion, the coverage of catalyst on copper surface gradually increases, and more cracks and gaps on the catalyst layer when Ni-P ratio reaches 2. This phenomenon leads to an increasement in hydrogen generation rate (HGR) because of larger effective reaction areas. However, with the increasing of Ni-P proportion, the open circuit potential of electrochemical system shifts negatively, as well as the impedance decreases sharply, but, the corrosion current density ( i_corr ) rises evidently, suggesting that the corrosion rate (CR) of Ni-P catalyst is accelerated and the electrochemical reaction activity is enhanced. This is probably due to a large number of defects and voids on the Ni-P catalyst surface. The selection of catalyst is defined as R, representing the ratio of HGR to CR, and the optimum Ni-P ratio is 1.5. At this point, the maximum value of R is 34.86, and the activation energy (E_a) of Ni-P catalyst is calculated to be 44.64 kJ/mol. After 50 cycles, the retention rate of HGR was 82.98 %, proving receivable hydrogen evolution efficiency and durability of Ni-P catalyst.