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.

Boosting the Catalytic Performance of NiMoO4 Nanorods in H2 Generation upon NH3BH3 Hydrolysis via a Reduction Process

“…To solve the problem above, ammonia borane (NH 3 BH 3 ) is recently expected to be a safe hydrogen storage material for efficient H 2 production, − because of its low molecular weight, excellent water solubility, superhigh hydrogen content (19.6 wt %), high stability, uninflammability, and environmental friendliness. − Although a range of noble metal catalysts, including Ru, Rh, Pd, Pt, and Au, have been developed for efficient H 2 generation upon NH 3 BH 3 hydrolysis at room temperature (eq ), there is a highly urgent need for exploring the earth-abundant metal nanocatalysts in H 2 generation upon NH 3 BH 3 hydrolysis. − As part of our ongoing research, , herein, we have reported a NaBH 4 reduction strategy to boost the catalytic performance of NiMoO 4 nanorods in H 2 generation upon NH 3 BH 3 hydrolysis. In particular, NiMoO 4 has attracted wide attention due to its low cost, fascinating electronic band structure, narrow band gap (2.5–2.9 eV), high surface area, excellent chemical/thermal stability, and environmental friendliness .…”