Bias-free glucose/O₂ bio-photoelectrochemical system for multi-energy conversion and phenolic pollutant degradation

Developing a multi-functional green energy device that propels sustainable energy development and concurrently purifies environmental pollutants offers an irresistibly compelling vision for a cleaner future. Herein, we reported a bias-free glucose/O₂ bio-photoelectrochemical system (BPECS) for both energy conversion and phenolic pollutants degradation. Coupling a glucose dehydrogenase (GDH) modified self-assembled meso-tetrakis (4-carboxyphenyl)-porphyrin (SA-TCPP)-sensitized TiO₂ biophotoanode for glucose oxidation and nitrogen/oxygen doped cobalt single-atom catalyst (CoNOC) cathode for two-electron oxygen reduction, both solar and biochemical energies were converted into electric power in BPECS with a maximum power density of 296.98 μW cm^-2 (0.49 V). Working in synergy with horseradish peroxidase (HRP) biocatalysis, the cathode-generated H₂O₂, a by-product, is effectively redeployed for degrading phenol, attaining an impressive degradation efficiency of approximately 100% within 60 min. Additionally, aiming to scale up this ingenious BPECS approach, peroxidase-mimicking Co₃O₄ nanozyme were engineered as a substitute for natural HRP. Remarkably, these nanozyme demonstrated a comparable degradation efficiency, achieving the same result in 90 min. In this work, our results demonstrate that this bias-free glucose/O₂ BPECS model marks a significant step forward in integrating renewable energy harvesting with environmental remediation, but also opens new avenues for the versatile application of nanozymes.