Advances in single-atom catalysts/sorbents for elemental mercury removal from flue gas

Abstract

Developing high-performance materials and techniques to capture elemental mercury (Hg0) from industrial flue gases is of great urgency to effectively mitigate anthropogenic Hg pollution and adequately fulfill the obligations imposed by the Minamata Convention on Mercury. Single-atom catalysts/sorbents as a novel group of efficient Hg0 remediators have filled new vitality into the field of Hg0 abatement because of their sufficient atomic utilization, extremely high catalytic/adsorption activity, excellent selectivity, and easy comprehension of reaction mechanism. However, there still lacks work to bridge previous studies and future developments in this area. Thus, this review orderly summarized Hg0 removal mechanisms, design and synthesis logics, characterization techniques, Hg0 removal performance comparisons, and influential factors including flue gas temperatures and components of single-atom catalysts/sorbents, aiming to reduce the knowledge barrier for exploiting more advanced single-atom based materials for Hg0 removal. Based on the current research achievements, future developments should concentrate on the enhancement of loading amount and stability of single-atom active sites, precise modulation of coordination configuration of metal ligands, and industrial-scale preparation and real-world application of single-atom catalysts/sorbents. Finally, research gaps from both macrocosmic and microcosmic perspectives were also put forward to provide certain valuable guidance for the future researches on single-atom catalysts/sorbents for Hg0 uptake from industrial flue gas.