Free-standing red phosphorous/silver sponge monolith as an efficient and easily recyclable macroscale photocatalyst for organic pollutant degradation under visible light irradiation

Traditional nano-sized photocatalysts in powdery form suffer from difficulties in recyclability, and have to be immobilized before practical applications. In this study, red phosphorous/silver (red P/Ag) sponge monolith was discovered to be a new free-standing macroscale photocatalyst, which was fabricated by a one-pot hydrothermal method without using any organic surfactants or templates for the first time. The elemental red P not only functioned as a reducing agent in the formation of Ag sponge monolith during the synthesis processes, but also as the active photocatalyst in-situ immobilized onto the Ag sponge. The as-prepared red P/Ag sponge monolith showed enhanced photocatalytic activity than that of traditional pure powdery red P by a factor of 3.1 times for organic pollutants (i.e. Rhodamine 6G, phenol) degradation under visible light irradiation. The enhancement was mainly attributed to the function of Ag sponge served as good electron sink to trap photo-generated electrons. More importantly, such free-standing macroscale photocatalyst can be easily recycled without activity deterioration. As a proof of concept, this work provides new insights into not only for the development of red P-based elemental photocatalysts, but also for the one-pot fabrication of novel free-standing macroscale materials with excellent photocatalytic activity for practical environmental applications. (C) 2018 Elsevier Inc. All rights reserved.