Fabrication of Cu2S hollow nanocages with enhanced high-temperature adsorption activity and recyclability for elemental mercury capture

Abstract

Transition metal sulfides have attracted great interest in nonferrous smelting industries for elemental mercury (Hg0) capture owing to their high activity, low cost and resistance to SO2. However, the major obstacle was the deactivation of active sites in adsorbents after the use or at high temperature. Herein, we fabricated rhombic dodecahedral Cu2S hollow nanocages by using high-quality Cu2O crystals as sacrificial templates. Benefiting from the unique structure and composition, such Cu2S hollow nanocages exhibited not only the enhanced high-temperature adsorption activity for Hg0 (120 °C, removal efficiency > 95%), but also had outstanding recyclability (five cycle, removal efficiency > 85%) without additional reactivation treatment. And the saturation adsorption capacity was about 26.6 mg∙g−1. Further study of the structure-performance correlation indicated that the environmental features of interior architecture might offer inner active S1- sites with the shelter of nanocage shell at high temperature, combining with Hg0 to form HgS. Besides, the recovered adsorption activity was ascribe to the thermal migration of active Cu2+ ions. Thus, this work provides a promising adsorbent for Hg0 capture at high temperature, while opening a new field to design hollow-structured materials for environmental applications.