Bamboo-like nitrogen-doped carbon nanotubes on iron mesh for electrochemically-assisted catalytic oxidation

In this study, bamboo-like nitrogen-doped carbon nanotubes (BN-CNTs) are successfully deposited on etched iron mesh (d-Fe) using chemical vapor deposition (CVD) method with acetonitrile as precursor. The acidic etching process is necessary for the special BN-CNTs structure formation by exposing more Fe⁰ sites. The BN-CNTs/d-Fe is then evaluated for the electrochemically-assisted PMS activation to degrade phenol. Under cyclic voltammetry (CV, 0-1 V vs. RHE) assistant, 20 ppm phenol can be degraded in 30 min with a rate constant of 0.2837 min^-1, ~78 times more than that without CV. Some Fe³⁺ species in the catalyst will be reduced at the initial stage, a two-step pseudo-first-order kinetic is thus used for the degradation curves fitting. Both the structure defects and doped nitrogen atoms are responsible for the high catalytic activity of BN-CNTs. According to the quenching tests, both radical and non-radical processes are present for PMS activation, thus obtaining enhanced organics removal efficiency. The electrochemically assistant could enhance the PMS adsorption on the electrode as well as electrons transfer between Feⁿ⁺ and PMS, thus increasing the PMS activation efficiency. The utilization of earth-abundant Fe mesh for the fabricating free-standing electrodes provide a potential low-cost and effective strategy of waste water remediation.