Theoretical investigations of non-noble metal single-atom catalysis: Ni₁/FeO_x for CO oxidation

Abstract

Significant progress has recently been made in single-atom catalysis involving noble metals. We report here a theoretical investigation on the catalytic mechanism of CO oxidation on a non-noble metal single-atom catalyst (SAC) Ni1/FeOx using density functional theory (DFT). The calculation results show that this new SAC Ni1/FeOx has high catalytic activity at room temperature for CO oxidation. The CO adsorption strength is a key factor in determining the catalytic activity for CO oxidation. Comparing with noble-metal Pt1/FeOx and Ir1/FeOx catalysts, the catalytic activity for CO oxidation on Ni1/FeOx is found to be comparable with that on Pt1/FeOx, but is considerably higher than that on Ir1/FeOx. Our theoretical prediction of this new non-noble metal Ni1/FeOx catalyst with high catalytic activity for CO oxidation at room temperature may find practical applications. The theoretical investigation provides fundamental understanding on the catalytic mechanism of singly-dispersed surface atoms and helps to stimulate further experimental study on highly active non-noble metal singleatom catalysts.

Single-Atom Catalysts: From Design to Application

“…Here, the calculations revealed that the reaction activation barrier of the rate-determining step in the catalytic cycle of CO oxidation was 0.62 eV higher and the adsorption energy for CO molecules was 0.69 eV higher for Ir 1 /FeO x catalysts as compared with Pt 1 /FeO x catalysts, accounting for the lower activity of the Ir 1 /FeO x catalysts. Moreover, in the search for low-cost catalysts for CO oxidation, Liang et al [98] used DFT calculations to predict that single Ni atoms anchored onto FeO x possessed higher catalytic activities at room temperature for CO oxidation that were comparable to that of Pt 1 /FeO x catalysts and were considerably higher than that of Ir 1 /FeO x catalysts in which the high activity for CO oxidation of the Ni 1 /FeO x catalyst at room temperature was attributed to the low energy barrier of the rate-determining step (Fig. 8c) Inspired by the discovery of highly active CO oxidation in Pt 1 /FeO x catalysts [11] and to develop more efficient and low-cost catalysts for CO oxidation, Chen et al [99] recently applied DFT calculations to systemically investigate the catalytic activity of various metal single atoms (Rh, Pd, Au, Co, Cu, Ru and Ti) supported on iron oxide surfaces and reported that among the various metal single-atom systems, the CO oxidation catalytic performances of oxygen-defective Rh 1 /FeO x , Pd 1 /FeO x and Ru 1 /FeO x catalysts ( Fig.…”

A Theoretical Investigation on CO Oxidation by Single‐Atom Catalysts M1/γ‐Al2O3 (M=Pd, Fe, Co, and Ni)

“…All spin‐polarized DFT calculations were performed by employing the Vienna Ab Initio Simulation Package (VASP) . The generalized‐gradient approximation in the form of PBE was used as the correlation and exchange energy functional, which has been widely used in previous DFT calculations of single‐atom catalysts . To describe the interactions between valence electrons and the ion core, the projector augmented wave (PAW) method was adopted .…”

1 + 1′ > 2: Heteronuclear Biatom Catalyst Outperforms Its Homonuclear Counterparts for CO Oxidation

“…In SACs, isolated individual atoms are dispersed on, and/or coordinated with, the surface atoms of an appropriate support, which maximizes the metal atom efficiency. Since the first SAC, single Pt atoms on FeO x , was reported in 2011, various SACs with metal oxide supports have been successfully fabricated, such as single Au/Pt/Ir/Ni/Os atoms on FeO x , Co 3 O 4 , CeO 2 , Al 2 O 3 , and MgO surfaces. At the same time, the SACs could be accessed by thermal atomization of supported metal nanoparticles and direct atoms emitting from bulk metals .…”