Hydrogen generation from formic acid decomposition on Ni(2 1 1), Pd(2 1 1) and Pt(2 1 1)

•Formic acid dehydrogenation on M(2 1 1) M = Ni, Pd, Pt was computed.•Formate route plays the dominating role.•CO2 has strong chemisorbed adsorption on M(2 1 1).•The activity of M(2 1 1) and M(1 1 1) has been compared.

The catalytic decomposition of formic acid into carbon dioxide and hydrogen (HCO2H → CO2 + H2) on M(2 1 1) (M = Ni, Pd, Pt) was investigated by using spin-polarized plane-wave based density functional theory calculations. It is found that on M(2 1 1) formic acid prefers the O (OC) atom atop adsorption and the H (HO) atom bridging two neighboring metal atoms, and formate prefers the bidentate adsorption with O atoms atop on metal surface. For M = Ni, Pd, Pt, formic acid has close adsorption energies (−0.69, −0.58, −0.61 eV) and also close dissociation barriers (0.42, 0.53, 0.51 eV), and the dissociation step is exothermic (−0.95, −0.44, −0.81 eV). Formate dissociation into surface CO2 and H (HCOO → CO2 + H) is the rate-determining step; and the effective barrier is higher on Ni(2 1 1) than on Pd(2 1 1) and Pt(2 1 1) (1.43 vs. 0.96 and 0.86 eV), and formate dissociation is endothermic (0.44 eV) on Ni(2 1 1), but exothermic on Pd(2 1 1) and Pt(2 1 1) (−0.09 vs. −0.19 eV). On M(2 1 1), CO2 has chemisorption (−0.32, −0.13, −0.27 eV for M = Ni, Pd, Pt, respectively). For formate dissociation, detailed comparisons between M(2 1 1) and M(1 1 1) show that Pd(1 1 1) and Pt(2 1 1) have the smallest effective barriers, while Pt(1 1 1) and Ni(2 1 1) have the largest effective barriers.

Graphical abstractFormic acid dehydrogenation on Ni(2 1 1), Pd(2 1 1) and Pt(2 1 1).Figure optionsDownload full-size imageDownload high-quality image (284 K)Download as PowerPoint slide