A Ni single-atom catalyst for advanced environmental disinfection based on electrochemical production of hydrogen peroxide

Abstract

With the increasing attention to environmental hygiene and air quality, the disinfection of bioaerosols has become a highly focused research area. Therefore, identifying a safe and efficient disinfection method to maintain indoor air quality is of critical importance. Hydrogen peroxide (H₂O₂) has garnered attention for environmental disinfection due to its broad-spectrum bactericidal properties and low toxicity. Herein, we employed the electrocatalytic 2e⁻ oxygen reduction reaction (ORR) to produce H₂O₂ and directly applied it for bioaerosol disinfection. In detail, our density functional theory (DFT) calculations demonstrated that a Ni single-atom catalyst with N and O coordination resulted in a partial transfer of electrons from the Ni atoms to the coordinated oxygen atom, which optimized the *OOH binding energy and enhanced 2e⁻ oxygen reduction activity to produce H₂O₂. Guided by the DFT calculations, we designed a Ni single-atom catalyst with a Ni–N₄–O structure for 2e⁻ ORR to produce H₂O₂. This catalyst achieved high H₂O₂ selectivities of 95% and 85% under alkaline and neutral conditions, respectively, and displayed a H₂O₂ production rate as high as 316.8 mmol per g metal per h in an H-type electrolytic cell. Finally, in our environmental disinfection system, the produced H₂O₂ was atomized into a small space for disinfection, achieving a high disinfection rate of 87% at 4 minutes and nearly 100% at 6 minutes. This study highlights the great potential of single-atom catalysts in the field of environmental disinfection.