The Integral Contribution of Metalloidal Boron in Electrocatalytic Removal of Nitrates and Organics

Abstract Nitrates and organic pollutants in agricultural, industrial, and domestic wastewater pose significant environmental and human health threats. Traditional electrochemical water treatment methods primarily rely on metallic materials as electrodes in either the cathode or anode, which are limited by low degradation efficiency and the secondary pollution resulting from metal leaching. Therefore, the development of efficient and stable non‐metallic electrodes is particularly urgent. Here, the boron‐carbon co‐deposition hypothesis is employed to synthesize a metalloidal boron/diamond matrix (MB/DM) layer, where boron is the active center for both cathodic and anodic reactions. The results demonstrate that the MB/DM cathode and anode can completely degrade 1000 mg L ⁻¹ nitrate and remove 98.9% of total organic carbon (TOC) from 100 mg L ⁻¹ phenol. By employing solar panels as a power source for treating mixed solutions of nitrate and phenol, high nitrogen selectivity (86.3%) and significant TOC removal (97.8%) in an MB/DM‐based two‐electrode system is achieved. Based on a combination of electrochemical experiments and density functional theory (DFT) calculations, the influence of boron atoms on the catalyst's redox state changes during the catalytic process is explained and discussed. This work presents an effective strategy for the simultaneous degradation of organic and inorganic compounds using non‐metallic MB/DM electrodes and offers theoretical support for the potential application of active boron in various redox processes.