Sustainable micro-activation of dissolved oxygen driving pollutant conversion on Mo-enhanced zinc sulfide surface in natural conditions

Abstract

The activation of inert oxygen (O2) often consumes enormous amounts of energy and resources, which is a global challenge in the field of environmental remediation and fuel cells. Organic pollutants are abundant in electrons and are promising alternative electron donors. Herein, we implement sustainable microactivation of dissolved oxygen (DO) by using the electrons and adsorption energy of pollutants by creating a nonequilibrium microsurface on nanoparticle-integrated molybdenum (Mo) lattice-doped zinc sulfide (ZnS) composites (MZS-1). Organic pollutants were quickly removed by DO microactivation in the MZS-1 system under natural conditions without any additional energy or electron donor. The turnover frequency (TOF, per Mo atom basis) is 5 orders of magnitude higher than those of homogeneous systems. Structural and electronic characterization technologies reveal the change in the crystalline phase (Zn-S-Mo) and the activation of π-electrons on six-membered rings of ZnS after Mo doping, which results in the formation of a nonequilibrium microsurface on MZS-1. This is the key for the strong interfacial interaction and directional electron transfer from pollutants to MZS-1 through the delocalized π-π conjugation effect and from MZS-1 to DO via Zn-S-Mo, as demonstrated by electron paramagnetic resonance (EPR) techniques and density functional theory (DFT) calculations. This process achieves the efficient use of pollutants and the low-energy activation of O2 through the construction of a nonequilibrium microsurface, which shows new significance for water treatment.