Graphene enhanced α-MnO2 for photothermal catalytic decomposition of carcinogen formaldehyde

Formaldehyde (HCHO) causes increasing concerns due to its ubiquitously found in indoor air and being irritative and carcinogenic to humans. Photothermal-catalysis developed in recent years has been considered as a significant strategy for enhancing catalytic activity. Manganese oxides, compared with its strong thermocatalytic activity, generally suffer from much lower photocatalytic activity make its photochemical properties less concerned. Herein, alpha-MnO2 nanowires were composited with the graphene oxide (GO) via mechanical grinding and co-precipitating method, respectively. alpha-MnO2/GO nanohybrids prepared by co-precipitating method exhibits excellent activity, achieving 100% decomposition of HCHO with the solar-light irradiation at ambient temperature. It is found that, besides the photo-driven thermocatalysis, the photocatalysis mechanism made a major contribution to the decomposition of HCHO. The incorporation of GO, on the one hand, is beneficial to improve the optical absorption capacity and photothermal conversion efficiency; on the other hand, is conductive to electron transfer and effective separation of electrons and holes. These synergistic effects significantly improve the catalytic activity of alpha-MnO2/GO nanohybrids. This work proposes a new approach for the utilization of solar energy by combining manganese oxides, and also develops an efficient photothermal-catalyst to control HCHO pollution in indoor air. (C) 2022 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

Formaldehyde is a widely present indoor air pollutant that is irritating and carcinogenic to humans. In this study, α-MnO2 nanowires were composited with graphene oxide (GO) to prepare α-MnO2/GO nanohybrids with excellent activity. These nanohybrids achieved complete decomposition of formaldehyde under solar-light irradiation at ambient temperature, demonstrating significantly enhanced catalytic activity. This work proposes a new approach for utilizing solar energy to control formaldehyde pollution in indoor air.