Rhodium nanoparticles confined in titania nanotubes for efficient Hydrogen evolution from Ammonia Borane

Designing efficient catalysts for hydrogen evolution from hydrolysis of ammonia borane (AB) have attracted considerable attention. Rhodium (Rh) based catalysts with rational design present remarkable catalytic performance for the reaction. Herein, we report the confined Rh@TiO2 catalysts synthesized by atomic layer deposition combining with the sacrificial template approach, in which the Rh nanoparticles are uniformly confined on the inner surface of the porous titania nanotubes. The optimized catalysts show high catalytic activity with a turnover frequency value of 334.1 mol(H2).mol(Rh)(-1).min(-1) and better durability. Mechanistic investigation demonstrates that the cleavage of OAH bands in water should be the rate determining step, and the appropriate concentration of NaOH can further enhance the hydrogen evolution activity. The catalysts can also achieve the hydrogenation of various organic substrates using AB as the hydrogen source. In addition, our present strategy is general and can be extended to the synthesis of other confined catalysts for various catalytic reactions. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

The study introduces a novel confined Rh@TiO2 catalyst for hydrogen evolution from hydrolysis of ammonia borane (AB), showing high catalytic performance and potential applications in hydrogenation of organic substrates. The catalyst is synthesized by atomic layer deposition and sacrificial template approach, demonstrating remarkable catalytic activity and durability. The research also suggests that the mechanism involves the cleavage of OAH bands in water and the importance of NaOH concentration in enhancing hydrogen evolution activity.