Enhanced oxidation resistance of CuCl@USY-MTMS composites through hydrophobic modification towards stable CO adsorption

To address the challenge that Cu + active species in developed Cu + -based adsorbents tend to oxidize to Cu 2+ in humid air, thereby losing their adsorption performance for carbon monoxide, in this study, methyltrimethoxysilane (MTMS) was employed as a hydrophobic modifier to modify the Cu + -based CO adsorbent. The hydrophobically modified Cu + -based CO adsorbent effectively shields the Cu + active species from water, thereby significantly inhibiting their oxidative deactivation. The successful grafting of MTMS onto the ultra-stable Y-type zeolite (USY) support was confirmed, thus markedly enhancing the hydrophobicity of the resulting Cu + -based CO adsorbent. The optimized adsorbent, CuCl(4)@USY-MTMS(24%), exhibits a high CO adsorption capacity of 2.61 mmol/g, coupled with high adsorption selectivity for CO/CO 2 and CO/N 2 . Moreover, the MTMS-modified hydrophobic CuCl(4)@USY-MTMS(24%) adsorbent exhibits significantly enhanced oxidation resistance compared to its unmodified counterpart, after aging in 70% relative humidity air for 24 h, it retains 79% of the CO adsorption capacity of pristine adsorbent, far exceeding the 47% retention of the unmodified version. This remarkable performance confirms that the hydrophobically modified adsorbent achieves stable CO separation.