Enhanced photocatalytic performance of ZnO/rGO composite materials prepared via an improved two-steps method

A series of ZnO/rGO composite materials were successfully prepared by an improved two-steps method. During the two-steps process, Zn2+ ions were firstly adsorbed and in-situ converted to Zn(OH)2 on GO sheets by the slow hydrolysis and then heat-converted to ZnO. At the same time, GO was partially reduced to rGO and further exfoliated and unfolded. Thus a real composite material ZnO/rGO was obtained. The photocatalytic performance of the as-prepared composite materials was higher than single ZnO and GO. The improved photocatalytic property of ZnO/rGO was mainly ascribed to the enhanced adsorption of MO, closely contact of ZnO and rGO, the quick electron transfer from excited ZnO particles to rGO sheets, the activation of MOad-rGO molecules via π–π interaction between MO and rGO to produce the activated species MOad−*-rGO, short diffusion length of the species MOad−* from rGO to ZnO particles, and strong oxidation power of ZnO-h+.