Nanolaminated MAB phase Mn2AlB2: An emerging ternary transition metal boride to efficiently activate periodate for antibiotic degradation

Periodate (PI) is emerged as a chemically stable, ecofriendly and safe solid-oxidant to execute advanced oxidation process (AOP) for water decontamination. Nevertheless, the robust catalytic system to efficiently trigger PI activation still remains scarce. The nanolaminated MAB phase Mn 2 AlB 2 consisting of the MnB bilayer interspersed with Al monolayers has been explored for the first time as a new Mn-based catalyst to activate PI for tetracycline (TC) elimination from water. The Mn 2 AlB 2 catalyst exhibits outstanding catalytic performance, achieving a considerable kinetic rate constant (k) of 0.1732 min −1 within 30 min, which is 5.99 times that of PI alone and even superior to counterparts of Al 3+ /PI, Mn 2+ /PI, H 3 BO 3 /PI, Mn 3 O 4 /PI and α-MnO 2 /PI systems. The free radicals of IO 3 and O 2 − combined with nonradical pathway ( 1 O 2 and electron transfer) are responsible for the TC elimination, as evidenced by quenching experiments, electron paramagnetic resonance (EPR) spectroscopy and in situ electrochemical tests. Besides, the TC degradation intermediates are determined and their related toxicities are assessed. This work unveils the PI activation on a new catalytic platform of nanolaminated MAB phase Mn 2 AlB 2 and provides new avenues for the rational design of advanced catalysts for PI-based AOPs.