B-Doped Porous Lignin Carbon/Copper-Iron Layered Double Hydroxides Catalysts Achieve Roxarsine Decontamination via Photocatalytic Oxalate Activation

Despite potential of layered double hydroxides (LDHs) in photocatalytic wastewater treatment was demonstrated, their practical applications remain constrained by inherent limitations including sluggish charge separation kinetics and insufficient stability. To overcome these critical challenges, we engineered a boron-doped porous lignin carbon loaded with copper-iron layered double hydroxides (B-PLC/CuFe LDH) photocatalyst through hydrothermal synthesis. The dual-modification strategy overcomes inherent limitations of conventional LDH systems through boron-induced electronic coupling and interfacial engineering. Boron doping modulates the electronic structure of the porous lignin carbon (PLC), strengthening interfacial interactions with CuFe LDH layers, while the hierarchical carbon framework enhances LDH dispersion and charge transfer efficiency. Systematic characterization (UV-DRS, Mott-Schottky) revealed that boron doping synergistically widened the composite's bandgap from 1.54 eV (pristine PLC) to 1.83 eV (B-PLC-3/CuFe LDH), while maintaining strong visible-light harvesting. According to Electrochemical impedance spectroscopy (EIS), boron doping reduced electrochemical impedance, and increased photogenerated radical formation (·O 2 - and ·OH), collectively enabling efficient arsenic pollutant degradation. The optimized B-PLC-3/CuFe LDH achieved 84.7% roxarsone (ROX) degradation within 60 min under visible light, outperforming pristine PLC by 2.05 times. This work establishes a new paradigm for overcoming LDH's intrinsic limitations through defect-engineered carbon hybridization, opening avenues for sustainable heavy metal remediation.