Fabrication via layered precursors and performance of N-doped biomass-carbon/ZnO/In2O3 composite photocatalyst for organic pollutant degradation

Layered double hydroxides (LDHs) have emerged as promising photocatalysts for effective pollutant degradation in wastewater treatment. In this study, a visible-light-responsive ZnO/In 2 O 3 composite photocatalyst incorporated with biomass-derived carbon ( [email protected] ) was synthesized via controlled calcination of Zn/In-containing binary LDH precursors with biomass carbon sources. The optimized [email protected] composite demonstrated remarkable performance in synergistic adsorption and photocatalytic degradation of crystal violet (CV), achieving high degradation efficiency (97.46 %) for 2000 mg/L CV under 460 nm LED light - significantly superior to the 54.79 % efficiency of pristine ZnIn-LDO. The photodegradation kinetic constant of [email protected] was 8.4 times higher than that of ZnIn-LDO. Systematic characterization revealed that the optimal BC incorporation engineered the optical and surface properties: it narrowed the bandgap, enhanced visible-light absorption, increased specific surface area, and most importantly, drastically promoted the separation and transfer of photogenerated carriers. Mechanistic studies identified that the improved charge dynamics drive an efficient oxygen reduction pathway, where superoxide radicals (·O 2 − ) and hydroxyl radicals (·OH), generated via H 2 O 2 intermediates, serve as the dominant active species. The degradation intermediates exhibited reduced phytotoxicity. This work provides a novel strategy for developing high-performance LDH-based photocatalysts by coupling biomass carbon to optimize interfacial charge separation and reaction kinetics.