Catalytic hydrolysis of ammonia borane (AB) has been considered as an effective and safe method to generate hydrogen. Development of highly active and low-cost catalysts is one of the key tasks for this technology. In this work, hexagonal CuCo₂O₄ nanoplatelets with a thickness of approximately 55 nm were prepared. In AB hydrolysis, those nanoplatelets exhibited ultrahigh catalytic activity with turnover frequency (TOF) of 73.4 mol_hydrogen min⁻¹ mol_cat⁻¹. As far as we know, this is one of the highest TOF values ever reported for non-noble metal catalysts. In addition, the effects of viscosity and different alkalis on the hydrolysis were also investigated. It is revealed that high viscosity of the reaction medium will retard the hydrolysis reaction. The presence of NaOH, KOH, and Na₂CO₃ in the reaction solution is favorable for hydrolytic process. In contrast, NH₃·H₂O will slow down the hydrolysis rate of ammonia borane. This work can provide some novel insight into the design of catalysts with both high performance and low cost. Besides, some findings in the present study can also offer us some information about how to improve the hydrolysis rates by optimizing the hydrolysis condition.

The catalytic hydrolysis of ammonia borane (AB) is a promising route to produce hydrogen for mobile hydrogen‒oxygen fuel cells. In this study, we have successfully synthesized a variety of Ni_0.5Cu_0.5Co₂O₄ nanocomposites with different morphology, including nanoplatelets, nanoparticles, and urchin-like microspheres. The catalytic performance of those Ni_0.5Cu_0.5Co₂O₄ composites in AB hydrolysis is investigated. The Ni_0.5Cu_0.5Co₂O₄ nanoplatelets show the best catalytic performance despite having the smallest specific surface area, with a turnover frequency (TOF) of 80.2 mol_hydrogen·min⁻¹·mol⁻¹_cat. The results reveal that, in contrast to the Ni_0.5Cu_0.5Co₂O₄ nanoparticles and microspheres, the Ni_0.5Cu_0.5Co₂O₄ nanoplatelets are more readily reduced, leading to the fast formation of active species for AB hydrolysis. These findings provide some insight into the design of high-performance oxide-based catalysts for AB hydrolysis. Considering their low cost and high catalytic activity, Ni_0.5Cu_0.5Co₂O₄ nanoplatelets are a strong candidate catalyst for the production of hydrogen through AB hydrolysis in practical applications.

Production of hydrogen by catalytically hydrolyzing ammonia borane (AB) has attracted extensive attention in the field of catalysis and energy. However, it is still a challenge to develop a both inexpensive and active catalyst for AB hydrolysis. In this work, we designed a series of MoO₃-doped MnCo₂O₄ (x) catalysts, which were fabricated by a hydrothermal process. The morphology, crystalline structure, and chemical components of the catalysts were systematically analyzed. The catalytic behavior of the catalyst in AB hydrolysis was investigated. Among these catalysts, MoO₃-doped MnCo₂O₄ (0.10) microspheres composed of nanosheets exhibited the highest catalytic activity. The apparent activation energy is 34.24 kJ mol⁻¹ and the corresponding turnover frequency is 26.4 mol_hydrogen min⁻¹ mol_cat⁻¹. Taking into consideration the low cost and high performance, the MoO₃-doped MnCo₂O₄ (0.10) microspheres composed of nanosheets represent a promising catalyst to hydrolyze AB for hydrogen production.