Tungsten(VI) oxide-supported nickel/silver nanoparticles for photocatalytic hydrogen evolution from ammonia-borane

Abstract

Developing efficient catalysts for hydrogen (H 2 ) evolution from ammonia-borane (AB, NH 3 BH 3 ) is crucial for fuel cell applications. Photocatalytic hydrolysis of AB by heterogeneous catalysts under light irradiation has attracted attention as an effective technique for H 2 evolution. Here, we report an impregnation-reduction method to prepare the tungsten(VI) oxide-supported nickel/silver nanoparticles (denoted as NiAg/WO 3 ) and their characterization by advanced tools such as ICP-OES, PXRD, SEM, TEM, and XPS. The initial turnover frequency (TOF), activation energy ( E a # ), activation enthalpy ( Delta H # ), and activation entropy ( Delta S # ) values of NiAg/WO 3 nanoparticles in H 2 evolution from AB under visible light irradiation are calculated as 56.6 molH 2 & sdot; molNi 0.27 Ag 0.73 - 1 & sdot; min -1 , 52.14 kJ & sdot; mol -1 , 47.78 kJ & sdot; mol -1 , and -91.62 J & sdot; mol -1 & sdot; K -1 , respectively. These findings are especially significant for a feasible application of AB in H 2 fuel cells.