DFT study of the water gas shift reaction on Ni(111), Ni(100) and Ni(110) surfaces

Nickel‐based Catalysts for High‐temperature Water Gas Shift Reaction‐Methane Suppression

“…Carboxyl and redox pathway are kinetically competitive on flat Ni (111) surface as both pathway have similar energy barriers whereas formate and formyl pathways are more favored on stepped Ni (211) surface . When compared to other pathways, formate intermediates are considered to be spectator species due to high dissociation barrier which implies that formate pathway is not the main reaction pathway ,. Steady state isotopic kinetic analysis (SSTIKA) and micro‐kinetic modeling provide experimental and computational evidences that formate intermediates are indeed inactive participants for WGS reaction …”

“…First reason is the undesirable CO/CO 2 hydrogenation to form methane [Eqs. (2)–(3)], second reason is the higher tendency of nickel to sinter at high temperature which causes catalyst deactivation. Production of methane should be avoided from the economical point of view, since it consumes hydrogen and lowers the efficiency and productivity of the hydrogen production process.…”

Unraveling the Role of the Rh–ZrO2 Interface in the Water–Gas-Shift Reaction via a First-Principles Microkinetic Study

“…As the surface redox pathway does not require the reduction and oxidation of the oxide support, it can, in principle, operate on the metal alone, and has been included in many DFT studies on the WGS on unsupported metal surfaces. [31][32][33][41][42][43] Surface redox was originally thought to be the main reaction mechanism on the Cu(111) surface, 40 however it was later shown in a DFT study that WGS proceeds through a carboxyl mechanism on Cu(111) instead. 31 The surface redox route has been recently shown to be the dominant mechanism for Ni/Al 2 O 3 in a combined computational and experimental study.…”

“…31 The surface redox route has been recently shown to be the dominant mechanism for Ni/Al 2 O 3 in a combined computational and experimental study. 18 Computational studies typically employ slab models to perform calculations for the WGS over metal catalysts, [31][32][33][41][42][43] however, since the slab contains only metal sites, the models completely ignore the possible role of the underlying oxide supports, and by extension, the catalyst-support interface. The forward and reverse WGS reactions over rhodium have also been previously studied employing slab models of the Rh(111)-facet.…”

Inhibiting Fe–Al Spinel Formation on a Narrowed Mesopore-Sized MgAl2O4 Support as a Novel Catalyst for H2 Production in Chemical Looping Technology

“…The production of hydrogen (as an energy carrier) from primary resources, such as methane and water, is industrially developed [1][2][3][4]. Hydrogen with high purity can be applied in different applications, such as fuel cells.…”