Synergy of dual photoelectrodes for simultaneous antibiotic degradation and CO2 reduction by Z-scheme PEC system

Herein, a dual-functional Z-scheme photoelectrochemical (PEC) system has been developed to simultaneously degrade sulfadiazine (SDZ) and reduce CO2 to liquid fuels. The photoanode, Ag-TiO2/Ti (Ag-TNTs), is prepared through anodization and photochemical deposition techniques, while the photocathode, ZnO/Cu2O/Cu (ZCC NRs) is fabricated using wet chemical oxidation and hydrothermal growth methods. Physicochemical and photoelectric characterization results demonstrate improved photoelectric response of the modified photoelectrodes. The dual-functional Z-scheme PEC system achieves a remarkable 89.1 % degradation of SDZ within 2 h, with CH3OH and C2H5OH yields of 10.0 and 5.6 mu mol/L, respectively, at a bias potential of -0.5 V. The enhanced reaction efficiency can be attributed to the synergistic effect between photoelectrocatalysis (PC) and electrocatalysis (EC), as well as the facilitated Z-scheme-like electron transfer between the photoanode and photocathode. & sdot;OH is identified as the primary active species, and the intermediates are both predicted and detected. DFT calculations are used to estimate the active sites of SDZ degradation and the adsorption of intermediates during CO2 reduction. The stability and energy cost of the system are also investigated to validate its practical applicability.