Pt/Ni双金属纳米溶胶的制备及催化制氢性能

采用化学共还原法制备了聚乙烯吡咯烷酮(PVP)稳定的Pt/Ni双金属纳米溶胶.采用紫外-可见光谱(UV-Vis)、透射电子显微镜(TEM)对所合成的Pt/Ni双金属纳米溶胶进行了表征, 并系统研究了PVP用量、还原剂用量和浓度、双金属比例对该双金属纳米溶胶催化剂催化性能的影响.结果表明, 所制备的双金属纳米溶胶的平均粒径在2.0 nm左右, Pt/Ni双金属纳米溶胶的催化活性比Pt及Ni单金属纳米溶胶的高, 当Pt/Ni摩尔比为1:4时, 纳米溶胶的催化活性最高, 其活性值为16640 mol_H2·mol_Pt^-1·h^-1.所制备的Pt/Ni双金属纳米溶胶催化剂具有很好的耐久性, 5次催化实验后该催化剂仍保持较高的催化活性.该双金属纳米溶胶催化NaBH₄水解反应的活化能为48 kJ/mol.

Preparation of Colloidal Pt/Ni Bimetallic Nanosols and Their Catalytic Activities for Hydrogen Generation from Hydrolysis Reaction of Sodium Borohydride

The hydrolytic dehydrogenation of sodium borohydride is a promising integrated technology as a way of hydrogen storage and hydrogen production. This paper reports a facile route for synthesizing the PVP stabilized Pt/Ni bimetallic nanosol by a chemical co-reduction process. The morphology, size, structure and composition of the resultant Pt/Ni bimetallic nanosol were characterized by transmission electron microscopy(TEM) and ultraviolet-visible(UV-Vis) spectrum. The effects of PVP dosage, reducing agent dosage, and metal composition in the hydrolysis of NaBH₄ were studied. The results indicate that the prepared Pt/Ni bimetallic nanosol have an average size of about 2.0 nm. The catalytic activities of the Pt/Ni bimetallic nanosol are superior to monometallic Pt or monometallic Ni, among which especially the Pt₂₀Ni₈₀ bimetallic nanosol shows the highest catalytic activity with a hydrogen generation rate of 16640 mol_H2·mol_Pt^-1·h^-1 at 303 K and an activation energy of 48 kJ/mol. In addition, the prepared Pt/Ni bimetallic nanosol has a good catalytic stability, and even keeps a higher catalytic activity after five runs test.