Lignin-supported (Bi,Ti)2(O,S)3 bimetal oxysulfide catalysts for efficient catalytic reduction of organic dyes and Cr(VI) in the dark

Herrin, the lignin extracted from Rice hull , Phyllostachys edulis , Cunninghamia lanceolata, and Populus tomentosa Carrière were used as a soft support to grow Ti-doped Bi 2 (O,S) 3 bimetal oxysulfide catalysts, labeled BT-Rh, BT-Pe, BT-Cl, and BT-Ptc, respectively. The catalytic reduction activity was investigated through the decolorization of methyl orange (MO), methylene blue (MB), and reduction of Cr(VI) solutions under dark. The lignin-supported BiTiOS improved crystallinity, decreased aggregate size, increased specific surface area, and enhanced electrochemical active sites, leading to improve electron transfer and accelerated reduction rates. The catalytic reduction activity of organic dyes and Cr(VI) was significantly improved with lignin-supported BiTiOS. The 5 mg BT-Pe catalyst completely reduced 100 mL of 50 ppm MO, MB, and Cr(VI) solutions in 6, 6, and 18 min, respectively, with the reaction kinetic rate of 0.6782, 1.090, and 0.1189 min −1 , and demonstrated good durability, maintaining a reduction rate of 95 % after six cycles. This work provides a feasible approach combining biomass/inorganic materials to treat industrial wastewater. • First time reported lignin-supporting (Bi,Ti) 2 (O,S) 3 bimetal oxysulfide via a facile method. • Lignin-supporting BiTiOS has excellent catalytic reduction activity and high stability. • Lignin-template increased the electrochemical active site and improve the electron transfer. • A reaction mechanism for the rapid catalytic reduction of pollutants in the dark is proposed.