Solution-phase conversion of glucose into semiconductive carbonaceous nanosheet photocatalysts for enhanced environmental applications

Abstract

Two-dimensional (2D) materials are important materials in environmental science and engineering. They have been widely used in environmental treatments. However, most of the 2D materials are obtained and synthesized from minerals. The sources are not very environmental-friendly. In this regard, it is a sustainable strategy to fabricate 2D materials by renewable precursors like glucose in biomasses. However, synthesis of 2D materials from glucose in water is still a great challenge mainly because of isotropy growth. Herein, we achieve an aqueous solution-phase synthesis of semiconductive 2D nanosheets by using renewable carbohydrates via hydrothermal method. Previously, glucose tend to form irregular or spherical particles in hydrothermal solution due to isotropy growth. In this work, the carbohydrate of glucose can be converted into hydrothermal carbonation carbon (HTCC) nanosheets in the presence of ethylenediamine and Fe3+/Fe2+/Co2+/Ni2+ ions in water. Firstly, a Maillard reaction occurs to activate sp3-sp2 conversion of carbon to form aromatic intermediates. Then, the metal ions will trigger the formation of the HTCC nanosheets. The thickness of the nanosheets is c.a. 2–8 nm. Compared with bulk HTCC, the nanosheets exhibit dramatical enhancement. The pure bulk HTCC suffers from very poor charge transfer efficiency, which does not has obvious activiity in photocatalytic disinfection and pollution degradation. By contrast, as a 2D materials, the HTCC nanosheet exhibits excellent charge transfer efficiency at the direction perpendicular to its surface, which exhibits remarkable activity in photocatalytic disinfection, pollution degradation, and Cr(IV) adsorption and reduction. As a new method for the synthesis of 2D material in water, this method will lead to the development of a new generation of carbon-based 2D materials.