Solar-driven steam generation on nitrogen-doped graphene in a 2D water path isolation system

Abstract

Solar-driven steam generation using photothermal materials is a green and promising approach to address clean water scarcity. In this work, the graphene oxide(GO) was synthesized by an improved Hummers method, and then GO was reduced by hydrothermal method and modified with nitrogen, called as NRGO. Then, we performed UV-VIS-NIR, XRD, Raman, FTIR and SEM characterization. In order to reduce the heat loss of bulk working liquid and improve the solar-to-heat conversion efficiency, the isolation system with 2D water path was used. The efficiency test of steam generation was performed under the solar intensity of 1000 Wm-2 for 1 h, and the photothermal conversion efficiency of reduced graphene oxide (RGO) and nitrogen-doped graphene (NRGO) was 73% and 87%, respectively. It was found that NRGO owned better solar absorption efficiency, lower thermal conductivity and porosity. NRGO was combined with insulated isolated system which can reduce the heat loss of bulk water, to improve photothermal conversion efficiency.