RESUMO
Gold nanoparticles (Au NPs) have attracted remarkable research interests in heterogeneous catalysis due to their unique physical and chemical properties. However, only small-size Au NPs (<7 nm) exhibit promising catalytic activity. In this work, dumbbell-like Au NPs (D-Au NPs) with average size of 37 × 11 nm were prepared by a secondary seed-mediated growth method to serve as novel photocatalyst for ammonia borane (AB) hydrolysis in the solution with specific pH value. Our results demonstrate that â °) the strengthened LSPR compensation effect could effectively remedy the loss of catalytic activity resulting from the size enlarging of D-Au NPs, proven by that the heating power of a single Au nanoparticle (Ps) and turnover frequency of AB molecules within 10 minutes of D-Au NPs are 52.5 and 3.89 times higher than that of spherical Au NPs; â ±) the extinction coefficient and Ps of D-Au NPs are almost 2.72 and 2.42 times as high as that of rod-like Au NPs, demonstrating the promoting structure-property relationship of dumbbell-like structure.; â ²) when the pH value of AB solution was lower than 6.0, the hydrolysis rate was highly promoted, indicating that H+ ions play an active role in the hydrolysis process. This work greatly extends the application of noble metals and provides a new insight into AB hydrolysis.