In recent years, research efforts have focused on the development of safe and efficient H 2 generation/storage materials toward a fuel-cell-based H 2 economy as a long-term solution in the near future. Herein, we report the development of Pd nanoparticles supported on carbon nanofibers (CNFs) via sol-immobilisation and impregnation techniques. Thorough characterisation has been carried out by means of XRD, XPS, SEM-EDX, TEM, and BET. The catalysts have been evaluated for the catalytic decomposition of formic acid (HCOOH), which has been identified as a safe and convenient H 2 carrier under mild conditions. The influence of preparation method was investigated and catalysts prepared by the sol-immobilisation method showed higher catalytic performance (Pd SI /CNF) than their analogues prepared by the impregnation method (Pd IMP /CNF). A high turnover frequency (TOF) of 979 h −1 for Pd SI /CNF and high selectivity (>99.99%) was obtained at 30 • C for the additive-free formic acid decomposition. Comparison with a Pd/AC (activated charcoal) catalyst synthesised with sol-immobilisation method using as a support activated charcoal (AC) showed an increase of catalytic activity by a factor of four, demonstrating the improved performance by choosing CNFs as the preferred choice of support for the deposition of preformed colloidal Pd nanoparticles.

Hydrogen is one of the most promising energy carriers for the production of electricity based on fuel cell hydrogen technology. Recently, hydrogen storage chemicals, such as formic acid, have been proposed to be part of the long-term solution towards hydrogen economy for the future of our planet. Herein we report the synthesis of preformed Pd nanoparticles using colloidal methodology varying a range of specific experimental parameters, such as the amount of the stabiliser and reducing agent, nature of support and Pd loading of the support. The aforementioned parameters have shown to affect mean Pd particle size, Pd oxidation, atomic content of Pd on the surface as well as on the catalytic performance towards formic acid decomposition. Reusability studies were carried out using the most active monometallic Pd material with a small loss of activity after five uses. The catalytic performance based on the Au–Pd atomic ratio was evaluated and the optimum catalytic performance was found to be with the Au/Pd atomic ratio of 1/3, indicating that the presence of a small amount of Pd is essential to promote significantly Au activity for the liquid phase decomposition of formic acid. Thorough characterisation has been carried out by means of XPS, SEM-EDX, TEM and BET. The observed catalytic performance is discussed in terms of the structure/morphology and composition of the supported Pd and Au–Pd nanoparticles.