Sythesis And Catalytic Properties Of Hollow Nickel-Based Bimetallic Nanoparticles

Currently,It is known that the nickel-based bimetallic catalysts generally have good selectivity and durability.Therefore,most researches focus on how to prepare the catalyst with higher activity as well as lower cost.In this work,The common non-noble metals Co and Fe were selected as the component of the nickel-based bimetallic catalyst.Two strategies of catalysts preparation were studied in detail to improve the performance of the catalyst.The Ni-Fe-B catalysts were prepared by co-reduction method,in which the procedure was modified with and without organic ligand.Five different ligands:tartaric acid,succinic acid,glycine,ethylenediamine and oxalic acid were studied to improve the performance of the catalysts on hydrogen production in sodium borohydride hydrolysis.The hydrogen production rate decreased in the following order:tartaric acid?succinic acid>glycine?no ligand>ethylenediamine?oxalic acid.Adding tartaric acid and succinic acid enhances the activity of Ni-Fe-B catalyst for hydrolyzing sodium borohydride.And the activation energy of the Ni-Fe-B catalyst controlled by tartaric acid is 46.0 kJ·mol^-1.The adding of tartaric acid and succinic acid increases the active sites of the catalyst,which is attributed to increase the content of nickel on the surface of the prepared catalysts.A series of Ni-Fe-B bimetallic catalysts with different replacement times were synthesized by displacement method,and used for hydrogen hydrolysis of sodium borohydride.The results indicate that the Ni-Fe-B-60 shows the best catalytic activity at40?,with a hydrogen production rate of 4 320 mL·min^-1 and activation energy for the NaBH₄ hydrolysis reaction of 35.4 kJ·mol^-1.The stability test of Ni-Fe-B-60 catalyst shows that the catalyst is relatively stable,and the catalyst activity is still 90%after 5cycles.The Ni-Co-B bimetallic catalysts were also synthesized by displacement method for the electrocatalytic oxidation of methanol.The results indicate that the Ni-Co-B-60/C electrode exhibits higher catalytic activity for the electrocatalytic oxidation of methanol at a replacement time of 60 min.More active sites are distributed on the catalyst surface,which is attributed to the fact that Ni-Co-B-60 is a hollow structure and the catalyst has the largest specific surface area.At the same time,the kinetic parameters of catalytic methanol oxidation using the best catalyst were also calculated,for example k₂=10.85L·mol^-1·s^-1,k₁=1.31exp?0.071FE/RT?s^-1,and k-₁=1.71×10⁹exp?-0.929FE/RT?s^-1 respectively.