Adsorption of Sulfur‐Containing Species on LaCrO₃ (001) Surface: A First‐Principles Study

Abstract

Density functional theory calculations are employed to investigate the adsorption of sulfur‐containing species on the (001) surface of LaCrO3 (LCrO). Molecular adsorption is found to be stable with H2S binding preferentially at O site on the LaO‐terminated surface. The adsorption of H2S molecule leads to the electrons transferring from the substrate to the molecule and the charges rearrangement within the molecule. In addition, the adsorption of the corresponding S‐containing dissociated species (SH and S) is investigated. SH and S are found to be preferentially bind at the Cr site. We further predict the adsorption energies of sulfur‐containing species increase following the sequence H2S<SH<S for all the adsorption sites on LCrO (001) surface. Based on the adsorption energy comparison, LCrO is more sulfur‐tolerant than traditional Ni‐based anode materials, which is qualitatively in line with available experimental results. This study provides a scientific basis for rational design of sulfur‐tolerant anode materials for SOFCs.

Weakly spin-dependent band structures of antiferromagnetic perovskite LaMO3(M = Cr, Mn, Fe)

“…For these electrochemical reactions, the surface geometry and the surface state related to Cr 2+ /Cr 3+ /Cr 4+ , Mn 2+ /Mn 3+ /Mn 4+ , and Fe 2+ /Fe 3+ play an essential role. So far, many theoretical calculations using density functional theory (DFT) [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] as well as mapping onto tight-binding or spin models [36][37][38] have been performed for these materials. Despite these many theoretical studies, there has been only little systematic comparison of all possible structures of AFM perovskite LaMO 3 (M = Cr, Mn, Fe) to find out the similarities and differences among them in particular in the spin-dependent feature of the electronic states.…”

Performance and sulfur poisoning of Ni/CeO2 impregnated La0.75Sr0.25Cr0.5Mn0.5O3−δ anode in solid oxide fuel cells

“…This fact implies that the formation of sulfides can take place in a lower H 2 S concentration when the absorbed sulfur is directly react with anode due to the higher adsorption energies of S than H 2 S on the anode surface. According the density functional theory (DFT) calculations [31], the higher adsorption energies of S on La (3.097 eV) and Cr (3.157 eV) site in LaCrO 3 compared with H 2 S on La (0.485 eV) and Cr (À2.295 eV) site indicate that the sulfur is more apt to absorb on the anode surface than H 2 S. The adsorbed sulfur on the anode surface and the further reactions with anode are the reason for anode performance degradation.…”