Development of Pdn/g-C3N4 adsorbent for Hg0 removal – DFT study of influences of the support and Pd cluster size
Artikel i vetenskaplig tidskrift, 2019

Elemental mercury in the flue gas is highly hazardous to the ecosystem. However, its removal from gas phase is of challenges as it is highly volatile, chemically very stable and insoluble in water. It is therefore imperative to develop novel adsorbents that are efficient in the removal of elemental mercury from gas mixtures. In this study, density functional theory (DFT) was adopted to assist the development of novel adsorbents for mercury removal based on the in-depth understanding of the adsorption of Hg0 on g-C3N4, single Pd atoms and Pdn(n=2–4) clusters as well as the influences of the support and the size of Pd clusters on Hg0 adsorption. It is found that Hg0 atoms are physically adsorbed on the pristine g-C3N4 and are chemisorbed on the pure Pdn clusters and the Pdn/g-C3N4. The strongest adsorption happens on the Pd2 cluster and the Pd3/g-C3N4, while single Pd atoms doped on the g-C3N4 do not adsorb Hg0 atoms effectively. For a Pd4 cluster, there are at least four adsorption sites for the adsorption of Hg0, while these sites become more active in the presence of the support and the number of active sites for Hg0 adsorption on a Pd4 cluster doped on the g-C3N4 becomes seven due to the enhanced charge transfer from Hg atoms to the Pd cluster and the g-C3N4 surface. The most charge transfers are found to take place in the case of Pd2, Pd2/g-C3N4 and Pd3/g-C3N4, indicating the most intensive interactions between Hg0 and these configurations. Moreover, the shortened Pd-Hg bonds in the Pd3/g-C3N4 and the Pd4/g-C3N4 also shows the enhanced mercury adsorption, while opposite phenomena were observed in the other two structures, i.e., the Pd/g-C3N4 and the Pd2/g-C3N4.

Adsorption energy

Density functional theory

Mercury capture

Pd cluster

g-C N 3 4

Författare

Shuai Liu

University of Nottingham Ningbo China

Lin Chen

Chalmers, Fysik, Kemisk fysik

Kompetenscentrum katalys (KCK)

Xueliang Mu

University of Nottingham Ningbo China

Mengxia Xu

University of Nottingham Ningbo China

Jiahui Yu

University of Nottingham Ningbo China

Gang Yang

University of Nottingham Ningbo China

Xiang Luo

University of Nottingham Ningbo China

Haitao Zhao

University of Nottingham Ningbo China

Tao Wu

University of Nottingham Ningbo China

Fuel

0016-2361 (ISSN)

Vol. 254 115537

Ämneskategorier

Oorganisk kemi

Materialkemi

Teoretisk kemi

DOI

10.1016/j.fuel.2019.05.120

Mer information

Senast uppdaterat

2019-07-15