BN nanoparticle/Ag hybrids with enhanced catalytic activity: theory and experiments

Hexagonal boron nitride nanoparticles (BNNPs) with different amounts of boron oxide on their surfaces were used as catalyst carriers. BNNPs/Ag nanohybrids were produced via ultraviolet (UV) decomposition of AgNO 3 in a mixture of polyethylene glycol and BNNPs. High temperature (1600 °C, 1.5 h) vacuum annealing of BNNPs promoted small size (5-10 nm) Ag nanoparticle (AgNPs) formation on BN surfaces with narrow size distribution, whereas using BNNPs in their as-produced state resulted in large AgNPs with various sizes. An increase in the B 2 O 3 content on the BNNPs surfaces (up to a certain point) during BNNP pre-annealing in air led to larger amounts of AgNPs on their surfaces. Experimental results were confirmed by theoretical calculations of the adhesion energy of the (111) Ag with (0001) h -BN and (100) B 2 O 3 surfaces. In contrast to the nonwettability of the h -BN surface by AgNPs, silver bound well to B 2 O 3 with the formation of a covalent bond at the interface. Excessive fraction of B 2 O 3 , however, was not beneficial in terms of obtaining the optimal contents of AgNPs. Results of catalytic activity tests demonstrated that BNNPs/Ag nanohybrids synthesized using BNNPs with an optimized amount of B 2 O 3 possess significantly enhanced catalytic activity compared to BNNPs without or with excess amounts of oxide. Finally, the catalytic activity of nanohybrids was theoretically analyzed using density functional theory (DFT) calculations. BNNPs/Ag nanohybrids with an optimal amount of B 2 O 3 demonstrated a higher catalytic activity.