Pt/Co和Pt/Ni双金属纳米溶胶制备及催化制氢

采用化学共还原法制备聚乙烯吡咯烷酮(PVP)稳定的Pt/Co和Pt/Ni双金属纳米溶胶，采用UV-Vis、TEM等对所合成的Pt/Co和Pt/Ni双金属纳米溶胶进行表征，研究了化学组成对双金属纳米溶胶催化剂催化NaBH4水解制氢的影响. 结果表明，所制双金属纳米溶胶的平均粒径约为2.0 nm，双金属纳米溶胶的催化能力高于单金属Pt, Co, Ni纳米溶胶，Pt/Co和Pt/Ni双金属纳米颗粒优异的催化性能可归因于电荷转移效应，Co或者Ni原子与Pt原子之间发生的电荷转移效应使得Pt原子带负电而Co或者Ni原子带正电，荷电的Pt和Co、Ni原子成为催化反应的活性中心，促进了催化反应的进行.

Preparation of Colloidal Pt/M(Co,Ni) Bimetallic Nanoparticles and Their Catalytic Activity for Hydrogen Generation

Polyvinylpyrrolidone stabilized Pt/M (M=Co or Ni) bimetallic nanosol was synthesized by a chemical co-reduction process, and its morphology, particle size, structure and composition were characterized by TEM and UV-Vis. The effects of composition on the hydrolysis of NaBH4 for hydrogen generation were also studied. The results indicate that the prepared Pt/M bimetallic nanosol particles have an average size of 2.0 nm. The catalytic activity of Pt/M bimetallic nanosol is superior to that of Pt, Co and Ni nanosols. The higher catalytic activity of Pt/M (M=Co or Ni) bimetallic nanosol over that of corresponding monometallic nanosol can be ascribed to electronic charge transfer effects. DFT calculations show that Pt atom is indeed negatively charged, while the Co or Ni atom has positive charge due to the electron donation from the Co or Ni atom to Pt atom. The positively charged Co or Ni atom and negatively charged Pt atom act as catalytic active sites for the hydrolysis reaction of alkaline NaBH4 solution for hydrogen generation.