Understanding the Impact of Defects on Catalytic CO Oxidation of LaFeO₃-Supported Rh, Pd, and Pt Single-Atom Catalysts

Abstract

Understanding the intrinsic catalytic properties of perovskite materials can accelerate the development of highly active and abundant complex oxide catalysts. Here, we performed a first-principles density functional theory study combined with a microkinetics analysis to comprehensively investigate the influence of defects on catalytic CO oxidation of LaFeO 3 catalysts containing single atoms of Rh, Pd, and Pt. La defects and subsurface O vacancies considerably affect the local electronic structure of these single atoms adsorbed at the surface or replacing Fe in the surface of the perovskite. As a consequence, not only the stability of the introduced single atoms is enhanced but also the CO and O 2 adsorption energies are modified. This also affects the barriers for CO oxidation. Uniquely, we find that the presence of La defects results in a much higher CO oxidation rate for the doped perovskite surface. A linear correlation between the activation barrier for CO oxidation and the surface O vacancy formation energy for these models is identified. Additionally, the presence of subsurface O vacancies only slightly promotes CO oxidation on the LaFeO 3 surface with an adsorbed Rh atom. Our findings suggest that the introduction of La defects in LaFeO 3 -based environmental catalysts could be a promising strategy toward improved oxidation performance. The insights revealed herein guide the design of the perovskite-based three-way catalyst through compositional variation.

Superior Catalytic Performance of Atomically Dispersed Palladium on Graphene in CO Oxidation

“…Low-temperature catalytic conversion of carbon monoxide (CO) to carbon dioxide (CO 2 ) via oxidation is one of the key parts of several chemical processes of industrial significance, including CO removal by preferential oxidation in H 2 -rich stream for fuel cell applications, 1−4 control of toxic contents in the exhaust gas from combustion engines and automobiles, 5,6 and so forth. Though noble-metal catalysts, including Pt, 7−15 Pd, 16−23 Rh, 24,25 Au, 26−29 Ir, 30,31 and so forth, are highly active in CO oxidation, they are expensive, and their performances are strongly dependent on the reaction conditions. 9,12,32 Considerable attention has been devoted to develop novel CO oxidation catalysts efficient at low temperatures.…”

Porous LaFeO3 nanofiber with oxygen vacancies as an efficient electrocatalyst for N2 conversion to NH3 under ambient conditions

“…To describe the effect of the exchange-correlation and the on-site Coulomb interaction, the Perdew, Burke, and Ernzerhof (PBE) functional [50] with the Hubbard + U correction was used. The effective U value for the Fe 3 d orbital was set to be 4 eV [51] . The weak van der Waals (vdW) interactions were described by the DFT + D3 method [52] .…”

Single‐atom Automobile Exhaust Catalysts

“…For example, DFT calculations on M 1 /LaFeO 3 (M=Rh, Pd, Pt) revealed that a M 1 /LaFeO 3 catalyst with a La defect demonstrated more optimized CO/O 2 adsorption and therefore better catalytic performance. [102] Among LaFeO 3 Rh, Pd, and Pt single atoms, Pd 1 / LaFeO 3 with a La defect presents the highest reactivity. A similar strategy was also applied to guide the design of M 1 / LaBO 3 (M=Rh, Pd, Pt; B=Mn, Fe, Co, Ni).…”

“…First‐principle calculations were performed recently on perovskite‐supported SACs to guide their design. For example, DFT calculations on M 1 /LaFeO 3 (M=Rh, Pd, Pt) revealed that a M 1 /LaFeO 3 catalyst with a La defect demonstrated more optimized CO/O 2 adsorption and therefore better catalytic performance [102] . Among LaFeO 3 Rh, Pd, and Pt single atoms, Pd 1 / LaFeO 3 with a La defect presents the highest reactivity.…”