Unveiling the CeO2 morphology effect in Pd-CeO2/C heterostructures catalysts for formic acid dehydrogenation

It is very crucial but still a huge challenge to develop efficient and durable catalysts to promote hydrogen production from formic acid (FA). Herein, three CeO2 with structurally well-defined different shapes, i.e., sCeO2 (spheres), rCeO2 (rod) and oCeO2 (octahedral), are prepared, and their effect on the crystal faces and oxygen vacancy over the constructed heterostructure catalysts (Pd-CeO2/C) have been intensively investigated in the FA dehydrogenation. Pd-sCeO2/C outperforms the other catalysts with a turnover frequency (TOF) value of 2691 h-1 and selectivity to hydrogen of 100 % at 30 degrees C. A synergism between the CeO2 (1 10) facet and more oxygen vacancies is considered to be key to obtaining the high reactivity. Moreover, biomass carbon promotes the dispersion of Pd-CeO2 heterostructures due to its large specific surface area and causes more defects in the Pd-CeO2/C. Combined with in-situ FTIR and density functional theory (DFT), it is speculated that FA is decomposed through formate pathway over the Pd-sCeO2/C. This work thus provides a reasonable design and controllable synthesis strategy for the effective application of FA as an available liquid phase hydrogen storage material.

Automated summary

CeO2 nanoparticles were found to enhance the catalytic activity in formic acid dehydrogenation, with CeO2 (110) surface and oxygen vacancies playing a key role. The addition of biomass carbon improved the dispersion of Pd-CeO2 heterostructures and increased defect density. This work provides a reasonable design and controllable synthesis strategy for the effective application of formic acid as a liquid phase hydrogen storage material.