Designing highly efficient and low-cost catalysts is essential toward realizing the practical application of hydrogen generation by formic acid decomposition (FAD) under ambient conditions. Herein, we report the synthesis of a hybrid material of Pd nanoparticles encapsulated within carbon nanotubes (CNTs) (Pd-CNTs-in). Transmission electron microscopy images show that most Pd nanoparticles (mean diameter 4.2 ± 0.8 nm) are located inside the nanotubes. Temperature-programmed reduction studies of H₂ reveal that the average reduction temperature of the Pd(II) species adsorbed on the interior wall of the CNTs is 12 °C lower than those adsorbed on the outer walls of the CNT. Moreover, the as-prepared Pd-CNTs-in catalysts show extremely high FAD activity and durability at ambient temperature. The turn over frequency (TOF) value is as high as 1135 h⁻¹ for the initial 10 min and does not decay significantly during the consecutive 3-time recycling studies. X-Ray photoelectron spectroscopy (XPS), surface-enhanced infrared spectroscopy (SEIRAS), and gas chromatography (GC) studies indicate that CNT confinement induced electronic structure modulation of Pd could be the major reason for the enhancement of FAD catalysis on the Pd-CNTs-in surface. This work could provide promising strategies for the fabrication of cost-effective and high-active Pd-based catalysts for formic acid dehydrogenation.

设计高效和低成本的催化剂对于实现在环境条件下通过甲酸分解（FAD）产生氢的实际应用至关重要。在这里，我们报告了碳纳米管（CNT）（Pd-CNTs-in）中封装的Pd纳米粒子杂化材料的合成。透射电子显微镜图像显示，大多数Pd纳米颗粒（平均直径4.2±0.8 nm）位于纳米管内部。H ₂的程序升温还原研究揭示了吸附在CNT内壁上的Pd（II）物种的平均还原温度比吸附在CNT外壁上的Pd（II）物种的平均还原温度低12°C。而且，所制备的Pd-CNTs-in催化剂在环境温度下显示出极高的FAD活性和耐久性。翻转频率（TOF）值高达1135 h ^-1在最初的10分钟内，并且在连续的3次循环研究中不会明显衰减。X射线光电子能谱（XPS），表面增强红外光谱（SEIRAS）和气相色谱（GC）研究表明，CNT限制诱导的Pd电子结构调节可能是增强FAD对Pd-的催化作用的主要原因。碳纳米管进入表面。这项工作可以为制造具有成本效益和高活性的基于Pd的甲酸脱氢催化剂提供有希望的策略。