Synergistic Adsorption and Catalysis on W-BiVO4@CoNi-MOFN Photoanode Toward Simultaneous Tetracycline Removal and H2 Generation

The efficient removal of low-concentration antibiotics from wastewater is a persistent challenge. In this work, we enhance the performance of a W-BiVO4 photoanode by modifying it with CoNi-based metal–organic framework nanosheets (CoNi-MOF), constructing a W-BiVO4@CoNi-MOFN composite. This integration markedly improves the separation and migration of photogenerated charge carriers. Consequently, the modified photoanode delivers a substantially higher photocurrent density of 3.92 mA cm−2 at 1.23 VRHE, representing a 2.3-fold enhancement over the pristine W-BiVO4 (1.74 mA cm−2). Furthermore, the photoelectrocatalytic (PEC) system employing the W-BiVO4@CoNi-MOFN photoanode demonstrates significantly superior degradation efficiency for low-concentration tetracycline compared to the system based on unmodified W-BiVO4. The performance enhancement is attributed to a dual mechanism. First, the CoNi-MOF modification optimizes the PEC performance of W-BiVO4, facilitating the generation of photogenerated holes and active oxidants. Second, the composite photoanode exhibits enhanced tetracycline adsorption via π–π stacking and hydrogen bonding, thereby promoting degradation kinetics. The photoanode also shows excellent reusability. Total organic carbon (TOC) analysis and biotoxicity tests confirm effective mineralization and reduced environmental toxicity. Furthermore, the system demonstrates promising concurrent cathodic hydrogen evolution. This work highlights the potential of the W-BiVO4@CoNi-MOFN-based PEC system for integrated wastewater treatment and hydrogen production.