Solar-powered detection of organic dyes using nitrogen-doped N-TiO₂/Ag₂O nanorod arrays

Organic pollutant detection has caused widespread concern regarding due to their potential environmental and human health risks. In this work, a nitrogen-doped titanium dioxide/silver oxide (N-TiO₂/Ag₂O) composite has been designed as a sensitive photoelectrochemical (PEC) monitoring platform of organic dyes. Sensitive determination relies on the outstanding PEC performance of N-TiO₂/Ag₂O. The improved PEC performance stems from the effective separation of photocarriers and the extended light response range provided by the narrowing bandgap and a p–n junction with N-TiO₂/Ag₂O. The N-TiO₂/Ag₂O electrode exhibits a photocurrent density of up to 2.2 mA/cm², demonstrating three times increase compared with the photocurrent density observed with the pure TiO₂ film. The linear detection range for rhodamine B (RhB), methylene blue (MB), and methyl orange (MO) is 0.2 ng/mL to 10 μg/mL with an ultrasensitive detection limit of 0.2 ng/mL without bias voltage. Due to the outstanding photocurrent density and sensitive response to organic pollutants, the N-TiO₂/Ag₂O PEC sensor provided a promising analytical method to detect environmental organic dyes.