Dispersion of copper species in a confined space and their application in thiophene capture

Abstract

Deep desulfurization via π-complexation adsorption is an effective method for the selective capture of thiophenic sulfur compounds. The adsorptive desulfurization capacity of an adsorbent has been demonstrated to strongly depend on the dispersion degree of active species. In the present study, a strategy was developed to promote the dispersion of copper species by directly using as-synthesized mesoporous silica SBA-15 as a support. The results show that the confined space between template and silica walls is highly efficient in dispersing the resultant guest oxide, and unusual CuO dispersion is realized. However, severe CuO aggregation occurs on the material prepared through the conventional method based on template-free SBA-15. Interestingly, copper precursors have a significant effect on the dispersion degree of the oxide, which decreases in the order nitrate > acetate > chloride. After autoreduction, the materials are active in adsorptive desulfurization, and the desulfurization performance relates well to the dispersion degree of the oxide. The present strategy allows template removal and precursor conversion in one step, avoids the repeated calcination in the conventional modification process, and saves time and energy. This strategy may open up an avenue for the design and synthesis of new functional materials by use of some particular micro environments.