Synthesis of Pellet-Based Pd/C Egg-Shell Catalysts for Reversible Hydrogen Storage in Formate/Bicarbonate

We report the scalable synthesis of egg-shell Pd/C pellet catalysts for the reversible formate/bicarbonate hydrogen-storage cycle. This system is inherently safe, nontoxic and allows for the easy control of hydrogen storage and release through pressure or temperature. A simple synthesis protocol with oxalic acid as a chelating additive furnishes a uniform and thin Pd shell. The optimized catalyst is active in both half-reactions, delivering hydrogen release rates up to 17.4 L h^-1 and 80 L of CO-free H₂ and TON/TOF values comparable to state-of-the-art powder systems while providing the handling advantages of pellets. Insights into catalyst reactivation strategies are provided to improve the stability of the optimal material during repeated use.