State Key Laboratory of Fine Chemicals, Dalian University of Technology , Dalian 116024, People's Republic of China.
ACS Appl Mater Interfaces. 2017 Feb 1;9(4):3749-3756. doi: 10.1021/acsami.6b15020. Epub 2017 Jan 20.
Ammonia-borane (NH·BH; AB) has been considered as an excellent chemical material for hydrogen storage. However, developing highly efficient catalysts for continuous hydrogen generation from AB is still a challenge for future fuel cell applications. The combination of Pt with Ni is an effective strategy to achieve active bimetallic nanocatalyst, and the particle size has proved to play a crucial role in determining its final activity. However, the synthesis of PtNi bimetallic catalyst in the size of highly dispersed clusters has always been a challenge. In this report, PtNi/NiO clusters coated by small-sized hollow silica (R-PtNi/NiO@SiO) were designed for efficient hydrogen generation from the hydrolysis of ammonia-borane. The newly designed catalysis system showed extremely high activity with the initial turnover frequency value reaching 1240.3 mol of H·mol of Pt·min, which makes it one the most active Pt-based catalysts for this reaction. Detailed characterization by means of scanning transmission electron microscopy, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy element mapping, etc. revealed that the excellent performance of R-PtNi/NiO@SiO is derived from the highly dispersed PtNi/NiO clusters and the reduction of extra Pt on the surface of PtNi/NiO clusters to Pt at relatively low temperature.
氨硼烷（NH·BH；AB）被认为是一种优秀的储氢化学物质。然而，开发用于 AB 连续制氢的高效催化剂仍然是未来燃料电池应用的一个挑战。Pt 与 Ni 的结合是实现活性双金属纳米催化剂的有效策略，颗粒尺寸已被证明在决定其最终活性方面起着至关重要的作用。然而，在尺寸上高度分散的簇中合成 PtNi 双金属催化剂一直是一个挑战。在本报告中，设计了由小尺寸空心二氧化硅包覆的 PtNi/NiO 纳米簇（R-PtNi/NiO@SiO），用于高效地从氨硼烷水解制氢。新设计的催化体系表现出极高的活性，初始周转频率值达到 1240.3 mol 的 H·mol 的 Pt·min，使其成为该反应中最活跃的 Pt 基催化剂之一。通过扫描透射电子显微镜、X 射线光电子能谱、能谱元素映射等详细的表征，揭示了 R-PtNi/NiO@SiO 的优异性能源于高度分散的 PtNi/NiO 纳米簇和在相对较低温度下将 PtNi/NiO 纳米簇表面多余的 Pt 还原为 Pt。
