Enhancing AsH₃ Detoxification via Electron-Deficient [Ni^III-OH (μ-O)] in a Nickel-Modified NaY Zeolite: A Pathway...

The transformation of toxic arsine (AsH₃) gas into valuable elemental arsenic (As⁰) from industrial exhaust gases is important for achieving sustainable development goals. Although advanced arsenic removal catalysts can improve the removal efficiency of AsH₃, toxic arsenic oxides generated during this process have not received adequate attention. In light of this, a novel approach for obtaining stable As⁰ products was proposed by performing controlled moderate oxidation. We designed a tailored Ni-based catalyst through an acid etching approach to alter interactions between Ni and NaY. As a result, the 1Ni/NaY-H catalyst yielded an unprecedented proportion of As⁰ as the major product (65%), which is superior to those of other reported catalysts that only produced arsenic oxides. Density functional theory calculations clarified that Ni species changed the electronic structure of oxygen atoms, and the formed [Ni^III-OH (μ-O)] active centers facilitated the adsorption of AsH₂*, AsH*, and As* reaction intermediates for As-H bond cleavage, thereby decreasing the direct reactivity of oxygen with the arsenic intermediates. This work presents pioneering insights into inhibiting excessive oxidation during AsH₃ removal, demonstrating potential environmental applications for recovery of As⁰ from toxic AsH₃.