Efficient and Selective Immobilization and Direct Conversion of Mercury Into Optical Material‐HgSe via Highly Active Trigonal Phase Selenium (t‐Se)

Abstract Industrial flue gas mercury emissions account for 30% of global atmospheric mercury emissions. While selenium‐based materials show potential in reducing mercury emissions, the aspect of mercury recovery is neglected amidst the pressing need for mercury resources. Unlike conventional adsorbent regeneration cycles, elemental selenium anchoring mercury directly yields valuable by‐products such as HgSe, a semiconductor with a narrow bandgap, considered ideal for optoelectronic devices. Amorphous selenium (α‐Se) exhibits high mercury removal efficiency at room temperature but converts to less active trigonal selenium (t‐Se) in high‐temperature industrial flue gas. The literature on the mercury removal behavior of t‐Se is limited. To address this issue, rod‐shaped selenium (Se‐rod) with specific exposed active crystal facets (101) and vacancy defects is synthesized, achieving an exceptional mercury adsorption capacity of 430.10 mg g⁻¹. Moreover, the optical performance of self‐produced HgSe surpasses those of commercial samples. Se‐rod can be utilized for mercury removal while also bridging the gap in mercury resource supply.