Wood-derived nanocellulose hydrogel incorporating gold nanoclusters using in situ multistep reactions for efficient sorption and sensitive detection of mercury ion

•A novel wood-derived nanocellulose hydrogel with gold nanoclusters was prepared.•This hydrogel simultaneously has effective adsorption and detection abilities.•Maximum sorption capacity of this hydrogel for Hg(II) ion reached 234.4 mg/g.•The hydrogel had sensitive detection ability with the detection limit of 0.09 μg/L.•Electrostatic, metallophilic and complexation interactions worked for sorption.