Development of a multi-active center catalyst in mediating the catalytic destruction of chloroaromatic pollutants: A combined experimental and theoretical study

[Display omitted] •Nb modified Cu-HZSM-5 catalyst had high resistance to Cl poisoning.•H2O preferentially adsorbed at Nb-Cu interfaces.•Cl preferentially adsorbed Nb sites that protected Cu and ensured O2 activation.•Inhibited CuCl2 formation led to less polychlorinated byproducts.•Catalyst designed with multiple active centers can solve environmental challenge. In this article, we unveiled the feasibility of designing a multi-active center catalyst system for the efficient destruction of chlorinated organics. Cu-HZSM-5 catalysts modified by Nb were developed, which was subsequently utilized for the catalytic elimination of chlorobenzene (CB). The underlying reaction mechanisms, particularly H2O activation and Cl adsorption/desorption behaviors, were explored using in situ DRIFTS, H2O-TPD and Density Functional Theory (DFT) calculations. Experimental results indicated that Brønsted acidic HZSM-5 and Nb-OH provided sufficient H protons to react with Cl, forming the HCl at low temperature and facilitating the Cl desorption. H2O molecule preferentially adsorbed on Cu-Nb interfaces, followed by dissociation on Cu sites, which generated enriched hydroxyls to form HCl. Dissociated Cl preferentially adsorbed on Nb sites that protected the active Cu species and maintained the activation of gaseous O2, thereby hindering electrophilic chlorination to form more toxic polychlorinated byproducts.