Submerged Photosynthesis of TiO2-CuO Hetero-nanoparticles for the Solar Photo-electrolysis of Multiple Environmental Hazardous Substances

Abstract

Environmental challenges have become a matter of great concern, requiring immediate attention. Agricultural pollution, such as ammonia discharge, and industrial pollution, including the abuse of organic dyes, present significant dilemmas for humanity. In response to these challenges, we propose an approach by synthesizing TiO2-CuO hetero-nanoparticles capable of degrading multiple hazardous environmental substances. Submerged photosynthesis of crystallites (SPSC) can synthesize or assist in the synthesis of metal oxides due to its simplicity and environmentally friendly nature. TiO2-CuO hetero-nanoparticles with varying Cu-Ti molar ratios were prepared, characterized, and evaluated for performance. The dispersion of CuO within TiO2 was found to be relatively uniform. Increasing the amount of added Cu resulted in an increase in CuO content until reaching the upper limit. Despite minor variations, all hetero-nanoparticle samples exhibited excellent solar light absorption performance. The simultaneous utilization of solar light illumination and electrochemical techniques synergistically enhanced the degradation process of these hazardous substances. The hetero-nanoparticle with a Cu-Ti molar ratio of 0.17 demonstrated the optimal photo-electrochemical degradation performance, exhibiting a 150% increase in degradation efficiency under solar light illumination compared to dark condition. Furthermore, it exhibited superior efficiency in the electrochemical degradation of RhB under solar light, degrading 32% more than solar light alone, and 2% more than electrochemistry alone. The mechanisms behind the fabrication and degradation processes were also discussed, elucidating the underlying principles driving the observed performance. In conclusion, our research highlights the potential of TiO2-CuO hetero-nanoparticles for solar light-assisted degradation of NH3 and RhB, showcasing their environmental applications.