A general strategy to prepare transition metal sulfide functionalized hierarchically porous carbons with multiple enzyme-like activities for simultaneous electrochemical sensing of ATP metabolites

A general strategy for the in-situ hydrothermal synthesis of transition metal sulfides functionalized hierarchically porous carbons (FeS2-HPC, Co9S8-HPC, Ni3S2-HPC, Cu2S-HPC, and ZnS-HPC) is proposed using different transition metal chlorides as metal sources and activators, sustainable agroforestry waste biomass (Citrus sinensis peel sponge layer) as a carbon source, sulfuric acid as a sulfur source, and silica colloid as a hard template. The introduction of both transition metal salts and silica colloids facilitate the adjustment of the pore structure. The added sulfuric acid promotes the degradation of the agroforestry waste biomass, which are conducive to the formation of porous carbons. The in-situ synthesis of transition metal sulfide particles and the sulfur doping improve the conductivity, electrocatalytic and enzyme-like activities of obtained composite materials. The FeS2-HPC with multiple enzyme-like activities and the best electrocatalytic activity is applied as a nanozyme electrochemical sensing platform for the simultaneous detection of three ATP metabolites with a limit of detection (LOD) of 0.069 μM for uric acid in a linear range of 0.3–200 μM, a LOD of 0.047 μM for xanthine in 0.3–100 μM, and a LOD of 0.21 μM for hypoxanthine in 0.7–300 μM. This work provides a new idea for the development of transition metal sulfides functionalized porous carbons from agroforestry waste biomass, and a theoretical basis for the fabrication of nanozyme electrochemical sensing platform for health assessment and disease prevention.