A copper-based sorbent with oxygen-vacancy defects from mechanochemical reduction for carbon disulfide absorption

Abstract

This work innovatively provides an efficient method to prepare a Cu-based sorbent with oxygen-vacancy (O_vac) defects via mechanochemical reduction of CuO for CS₂ absorption. Crystalline structures based on XRD measurement show that mechanical force can lead to CuO reduction and O_vac defect generation during ball milling of CuO with Mg as a reducing agent. Sulfur content measurement shows that the prepared Cu-based sorbent with O_vac defects can realize efficient CS₂ absorption at 150 °C with a breakthrough sulfur capacity of 10.7 wt%. Electronic structures based on first-principles calculation show that the O_vac defects can decrease copper coordination, increase the surface energy and electron density, and reduce the band gap by forming coordinatively unsaturated Cu, which benefit the chemisorption of CS₂ molecules. Cu₂O with O_vac defects, the main phase for CS₂ absorption in the sorbent, can grab CS₂ molecules by the trapping effect of its O_vac defects with a chemisorption distance of 1.53 Å and an energy of −110.45 kJ mol⁻¹, and offer electrons for breaking C–S bonds. This work paves a new pathway for the preparation of Cu-based sorbents with high performance for sulfur compound absorption.