Efficient photoelectrocatalytic degradation of amoxicillin using nano-TiO₂ photoanode thin films: A comparative study with photocatalytic and electrocatalytic methods

Excessive utilization of antibiotics in human, animal, and aquaculture poses a substantial threat to human health and the environment. Photoelectrochemical processes are increasingly applied for water remediation because they generate oxidizing species and mineralize organic pollutants, making even small water quantities more amenable for utilization. Thus, this study presents the fabrication of an efficient nano-TiO₂ photoanode thin film (PATF) specifically designed for the photoelectrocatalytic (PEC) degradation of amoxicillin (AMX). The TiO₂ PATFs were deposited on fluorine-doped tin oxide (FTO) substrate using an ultrasonic spray pyrolysis process with various titanium isopropoxide (TTIP) acetylacetone (AcacH) molar ratios (1:1 to 1:10). The PEC oxidation of AMX was investigated using various molar ratios of TTIP:AcacH TiO₂ PATF/FTO by linear sweep voltammetry, and a 1:8 M ratio of PATF exhibited superior PEC oxidation activity than other TiO₂ PATFs. Subsequently, the PEC degradation efficiency of AMX was compared with that of photocatalytic (PC) and electrocatalytic (EC) methods. The results demonstrated that the PEC process effectively eliminated 76.2% of AMX within 120 min at 0.8 V, outperforming the removal rates attained by the EC (32.3%) and PC (52.6%). Notably, increasing the voltage to 1.0 V accelerated the PEC degradation of AMX, attaining a removal efficiency of 91.2% within 90 min and exceeding 95% within 120 min.