Co3O4 with upshifted d-band center and enlarged specific surface area by single-atom Zr doping for enhanced PMS activation

In this work, single-atom Zr doping is demonstrated to be an effective strategy to enhance the catalytic performance of Co3O4 toward peroxymonosulfate (PMS) by modulating electronic structure and enlarging specific surface simultaneously. The d-band center of Co sites upshifts owing to different electronegativity of Co and Zr in the bonds of Co-O-Zr confirmed by density functional theory calculations, leading to enhanced adsorption energy of PMS and strengthened electron transfer from Co(II) to PMS. The specific surface area of Zr-doped Co3O4 increases by 6 times due to the decrease of crystalline size. Consequently, the kinetic constant of phenol degradation with Zr-Co3O4 is 10 times higher than that with Co3O4 (0.31 vs. 0.029 min−1). The relative surface specific kinetic constant of Zr-Co3O4 for phenol degradation is still 2.29 times higher than that of Co3O4 (0.00660 vs. 0.00286 g m−2 min−1). In addition, the potential practical applicability of 8Zr-Co3O4 was also confirmed by practical wastewater treatment. This study provides deep insights into modifying electronic structure and enlarging specific surface area to enhance the catalytic performance.