Preparation of colloidal Pd/Ni bimetallic nanoparticle catalysts and their catalytic activity for hydrogen generation from hy

Abstract:

This paper reports a facile route for synthesizing PVP stabilized Pd/Ni bimetallic nanosol by chemical co-reduction process. The morphology, size, structure and composition of the resultant Pd/Ni bimetallic nanosol were characterized by transmission electron microscopy (TEM). The effects of amount of PVP, reducing agent and metal composition on the hydrolysis of NaBH4 were studied. The results indicate that the catalytic activities of the prepared Pd/Ni bimetallic nanocatalysts with an average size of 2 nm were superior to that of monometallic Pd nanocatalyst with the same size. The Pd10Ni90 bimetallic nanosol showed the highest catalytic activity with hydrogen generation rates of 8,250 mol-H?molPd-1?h-1 at 303 K, And the activation energy, enthalpy and entropy of Pd20Ni80 bimetallic nanoparticles 35.7 kJ/mol, 33.3 kJ/mol and -150 J/mol respectively. In addition, the prepared Pd/Ni bimetallic nanosol had a good catalytic activity even after the fourth cycle. The high catalytic activity of the Pd/Ni BNPs can be ascribed to electronic charge transfer effects. And DFT calculations showed that Pd atoms were indeed negatively charged with the positively charged Ni atoms. The positively charged Ni atoms and negatively charged Pd atoms acted as catalytic active sites for the hydrolysis of the alkaline NaBH4 solution.