Stimulating MgO defects exposure by nitrogen doping within activated carbon to enhance H2S catalytic oxidation

Abstract

Metal oxide-loaded catalysts are extensively used for room temperature catalytic oxidation of H₂S due to their strong affinity for H₂S, but tend to exhibit poor activity due to uneven dispersion. Herein, a series of nitrogen and MgO co-modified activated carbon was synthesized using the co-impregnation method. The desulfurization efficiency of the optimal material exceeded the individual contributions of nitrogen doping and MgO loading by nearly 25 %, achieving a remarkable 742.67 mg/g. This enhancement was partly attributed to the synergistic interaction between electron-rich pyridine N and MgO, promoting oxygen vacancies formation, which favored O₂ activation. Moreover, the substitutional nitrogen defects in MgO induced the formation of adjacent magnesium vacancies, increasing the number of strong basic sites favorable for H₂S dissociation. The modification strategy adopted in this study is also applicable to commercial activated carbon, providing a feasible approach for developing cost-effective low-temperature technology.