Facile Preparation of Cu(I)/5A via One-Step Impregnation with Highly Dispersed CuCl in Ethanol Single Solvent toward Selective Adsorption of CO from H₂ Stream

Cuprous ion-based zeolites have been proven as promising carbon monoxide (CO) adsorbents by virtue of their excellent adsorption and regeneration properties due to π complexation. However, existing preparation methods still suffer from the problems of a cumbersome process and low loading amounts of cuprous ions. Herein, we proposed a one-step synthesis strategy of using ethanol as a solvent to provide a reducing protective environment, which enabled the facile and controllable preparation of highly dispersed CuCl over 5A zeolites. Using CuCl as a copper source, to ensure the integrity of the 5A zeolite structure, CuCl species were directly loaded onto the 5A support in one step. Ethanol solution could effectively protect Cu­(I) from being oxidized by oxygen in air and improve the stability of cuprous ions in Cu­(I)/5A adsorbents. The results demonstrated that the Cu­(I)/5A prepared by this method exhibited a superior CO adsorption performance to the pristine 5A zeolite. The adsorption capacity of CO over Cu­(I)/5A attained 3.44 mmol·g^–1 at 298 K and atmospheric pressure, which was evidently superior to those of CuY (2.7 mmol·g^–1) and CuSAPO34 (1.84 mmol·g^–1) reported in the literature, while the adsorption capacity of H₂ was only 0.069 mmol·g^–1 under the same condition. According to the ideal solution adsorption theoretical model, CO was preferentially adsorbed and the IAST selectivity of CO in the CO/H₂ binary mixture over Cu­(I)/5A was about 273.4. This study provides a novel and effective way to synthesize high-efficiency CO adsorbents.