Insights into hydrogen generation from formic acid on PtRuBiOx in aqueous solution at room temperature

The catalytic dehydrogenation of formic acid (HCOOH) on heterogeneous catalysts in aqueous solution to produce CO-free H2 has received intense investigation due to its promising application in portable power devices. In this work, we present a study on the mechanism of HCOOH dehydrogenation on the PtRuBiOx catalyst using density functional theory (DFT) calculations supported by complementary experiments. The catalystʹs activity at room temperature was clarified by investigating HCOOH dehydrogenation on PtRu alloy and Bi2O3 surface with a focus on the key reaction steps. The PtRu with different alloying degree was modeled by a four-layer p (2 × 2) unit cell with Pt-skin and leaving Ru atoms in the second and the third layer based on the surface energy and the formation energy. The Bi2O3 surface was represented by the most stable (111) surface of δ-Bi2O3. Based on the computational and experimental results, a reaction pathway for HCOOH dehydrogenation on the PtRuBiOx in aqueous solution was proposed. The results suggest that the promotion of HCOOH dissociation on the Bi2O3 surface and the ligand effect between Pt and Ru are responsible for the activity of PtRuBiOx toward HCOOH dehydrogenation in aqueous solution at room temperature. Furthermore, the PdBiOx system was also prepared and investigated as a catalyst for HCOOH decomposition at room temperature. The catalytic behavior of PdBiOx for HCOOH dehydrogenation in aqueous solution was compared with that of the PtRuBiOx.