Energy-efficient electrochemical oxidation of flupyradifurone by W-modified blue TiO2 nanotube array anodes with intermittent current operation

W-modified blue TiO 2 nanotube anodes enhanced FPF oxidation and mineralization. • Intermittent current operation lowered energy input and mitigated activity decay. • Quenching and EPR analyses identified •OH as the dominant oxidizing species. • Transformation pathways and predicted toxicity evolution were evaluated. This study developed W-modified blue TiO 2 nanotube arrays (W-modified B-TiO 2 NTA) as an energy-efficient anode for electrochemical oxidation of flupyradifurone (FPF), with boron-doped diamond (BDD) used as a benchmark. W modification and cathodic reduction retained the anatase nanotubular structure, increased double-layer capacitance, and facilitated interfacial charge transfer. Compared with B-TiO 2 NTA, W-modified B-TiO 2 NTA accelerated FPF degradation, enhanced mineralization, and reduced energy consumption, with an apparent rate constant of 1.77 × 10 −2  min −1 , compared with 1.97 × 10 −2  min −1 for BDD under the tested conditions. The 50 s on/10 s off intermittent current mode further lowered energy input and mitigated activity decay during cycling. Quenching and EPR analyses showed that •OH dominated FPF oxidation, with a possible contribution from sulfate-derived radicals. HRMS-based tentative product assignment and DFT calculations suggested hydroxylation, oxidative C N cleavage, butenolide ring opening, dealkylation, and further oxidation as plausible transformation routes. Toxicity prediction indicated an overall decline in predicted residual toxicity after prolonged electrolysis. Download: Download high-res image (172KB) Download: Download full-size image