Facile construction of three-dimensional netted ZnIn2S4 by cellulose nanofibrils for efficiently photocatalytic reduction of Cr(VI)

[Display omitted] •The presence of COO–-Zn2+ between CNFs and ZnIn2S4 leads to the 3D netted structure.•The photocatalytic activity of Cr(VI) reduction highly enhanced over CNFs/ZnIn2S4.•The 3D netted structure strengthen the light via light penetration and scattering.•The enhanced photocatalytic activities are caused by the unique 3D netted structure. High-performance three-dimensional (3D) netted ZnIn2S4 was achieved by the ionic connection between COO– of TEMPO-cellulose nanofibrils (CNFs) and Zn2+ of ZnIn2S4 via a facile one pot synthesis. The newly-formed COO–-Zn2+ bond connection was clearly confirmed by the shifts of relative peaks in their Fourier transform infrared and X-ray photoelectron spectroscopy spectra. The prepared CNFs/ZnIn2S4 composites exhibited dramatic enhancement of photocatalytic activity for Cr(VI) reduction under visible-light irradiation compared to that of pure ZnIn2S4 and CNFs. Particularly, the photocatalytic efficiency of C/ZIS-0.4 (40 wt% CNFs to ZnIn2S4) is 2.1 times as high as that of pristine ZnIn2S4 (CNFs have almost no photocatalytic activity). On the basis of all experimental results, it can be deduced that the specific 3D netted structure of CNFs/ZnIn2S4 could provide much efficient light-harvesting triggered by light penetration and scattering, abundant exposed active sites, decreased charge transport distance and good hydrophilia, which are responsible for its boosted photocatalytic activity. This study could enlighten people for developing high-efficiency photocatalysts via morphologies design guided by bond connection.