Efficient Bias-Free Degradation of Sulfamethazine by TiO2 Nanoneedle Arrays Photoanode and Co3O4 Photocathode System under LED-Light Irradiation

Solving high electrical-energy input for pollutants degradation is one of the core requirements practical application photoelectrocatalytic (PEC) technology. Herein, we developed a self-driven dual-photoelectrode PEC system (TiO2 NNs-Co3O4) composed TiO2 nanoneedle arrays NNs) photoanode and Co3O4 photocathode first time. Under light-emitting-diode (LED) illumination, bias-free NNs-Co3O4 exhibited excellent performance, with an internal bias as 0.19 V, achieving near complete (99.62%) sulfamethazine (SMT) pseudo-first-order rate constant 0.042 min−1. The influences solution pH, typical inorganic anions, natural organic matter, initial SMT concentration on performance were investigated. Moreover, main reactive oxygen species (h+, •OH, •O2−) in decomposition elaborated. feasibility efficient water purification this unbiased was evaluated. It proved that NNs provided negative while positive photoanode, which made operate without external bias. This work elucidated cooperative mechanism photoelectrodes, providing guidance to develop sustainable, efficient, energy-saving wastewater treatment.