Nitrogen-phosphorus co-functionalized reduced graphene oxide supported NiCoPd-CeOx nanoparticles as a highly efficient and stable catalyst for formic acid dehydrogenation

Abstract

Formic acid (HCOOH, FA), a common liquid hydrogen storage material, has attracted tremendous research interest. However, the development of efficient, low-cost and high-stable heterogeneous catalyst for selective dehydrogenation of FA remains a major challenge. In this paper, a simple co-reduction method is proposed to synthesize nitrogen-phosphorus co-functionalized rGO (NPG) supported ultrafine NiCoPd-CeO x nanoparticles (NPs) with a mean size of 1.2 nm. Remarkably, the as-prepared Ni 0.2 Co 0.2 Pd 0.6 -CeO x /NPG shows outstanding catalytic activity for FA dehydrogenation, affording a high TOF value of 6506.8 mol H 2 mol Pd −1 h −1 at 303 K and a low activation energy of 17.7 kJ mol −1 , which is better than most of the reported heterogeneous catalysts, and can be ascribed to the combined effect of well-dispersed ultrafine NiCoPd-CeO x NPs, modified Pd electronic structure, and abundant active sites. The reaction mechanism of dehydrogenation of FA is also discussed. Furthermore, the optimized Ni 0.2 Co 0.2 Pd 0.6 -CeO x /NPG shows excellent stability over 10 th run with 100% conversion and 100% H 2 selectivity, which may provide more possibilities for practical application of FA system on fuel cells. • N–P co-functionalized rGO supported ultrafine NiCoPd-CeO x NPs are successfully synthesized via a simple co-reduction method. • NPG has a positive effect on improving the distribution and controlling particle size. • The Ni 0.2 Co 0.2 Pd 0.6 -CeO x /NPG exhibits high activity towards FA dehydrogenation, giving a TOF of 6506.8 h −1 at 303 K. • The Ni 0.2 Co 0.2 Pd 0.6 -CeO x /NPG shows excellent stability and activity even after 10 th run.