Rational 3D Structure of Monolithic Catalysts for Enhanced Hydrolytic Dehydrogenation of Ammonia Borane

Abstract

Monolithic catalysts have irreplaceable advantages in hydrogen (H2) production through catalytic dehydrogenation from liquid-phase hydrogen storage materials. However, monolithic catalysts suffer from an inevitable reduction in accessible active sites due to the reduced specific surface area and hindered mass transfer. Therefore, a rational three-dimensional (3D) structure of monolithic catalysts is needed to adjust the structural factors for maximizing performance. Herein, a series of efficient and low-cost 3D catalysts with designed periodic structures were successfully fabricated. Due to the optimized specific surface area and bubble transport of the elaborate 3D structure, compared to the disordered foam structure, the new series of monolithic catalysts showed 2.3- and 1.6-fold improvement in overall catalytic performance at 298 and 318 K without any change in physiochemical characteristics, with hydrogen generation rates of 2548 and 3885 mL gcat–1 min–1, respectively. In addition, a three-period structural design philosophy for 3D catalysts was summarized, and the concept of surface activity was introduced to provide quantifiable criteria for guidance of structural optimization. The outcomes in this paper may open up new insights for building high-efficiency monolithic catalysts.