Ho ³⁺ /Yb ³⁺ Co‐Doped Bi ₂ WO ₆ With Bifunctional Carbon Nanoparticles for Enhanced Visible‐To‐NIR Photothermal‐Assisted Photocatalysis

ABSTRACT To address inefficient near‐infrared (NIR) absorption and rapid charge carrier recombination in traditional photocatalysts, we synthesized Ho ³⁺ /Yb ³⁺ co‐doped Bi ₂ WO ₆ (HY‐BWO)/N‐doped carbon nanoparticle (CNP) composites. Ho ³⁺ /Yb ³⁺ co‐doping broadens the photoresponse into the NIR region via upconversion. Simultaneously, CNP form intimate Ohmic junctions with HY‐BWO nanosheets. The CNP function dually as a cocatalyst for accelerated interfacial charge transfer and as a photothermal enhancer by capturing upconverted photons, significantly improving visible‐to‐NIR photothermal‐assisted photocatalysis. Under visible light (λ ≥ 420 nm), the optimal Ho ³⁺ /Yb ³⁺ co‐doped Bi ₂ WO ₆ /N‐doped carbon (HY‐BWO‐C) composite achieved 93.29% tetracycline (TC) degradation within 40 min and 79% total organic carbon (TOC) removal at 120 min, demonstrating exceptional mineralization. Under NIR irradiation (λ ≥ 980 nm), the kinetic rate constant of HY‐BWO‐C was 4.33 times higher than that of pristine Bi ₂ WO ₆ . Mechanistic analyses revealed that O ₂ ⁻ and h ⁺ are the primary reactive species driving TC degradation. Furthermore, HY‐BWO‐C demonstrated excellent cyclic stability. This work presents a highly effective, full‐spectrum‐responsive photocatalytic platform for the practical elimination of antibiotic pollutants in aquatic environments.