Unsaturated Nd-Bi dual-metal sites enable efficient NIR light-driven O2 activation for water purification

Metal semiconductor catalysts with oxygen vacancies can make full use of near infrared light to active O2 for degradation of emerging pollutants. However, the surface oxygen vacancies can also become the combination center of electron-hole pairs, leading O2 cannot accept more electrons for activation, often becoming the bottleneck. In this study, by doping half-metal BiO2−x with Nd to form unsaturated Nd-Bi dual-metal sites as oxygen chemisorption and electron transfer sites, this bottleneck can be well solved. Systematic characterization results imply that Nd-Bi dual-metal sites can raise the center of the defect band to the Fermi level, which preserves the energy of photoexcited electrons. Thus, more electrons are driven to adsorbates for O2•- generation. Under liquid phase determination conditions, the modified sample achieves the reaction-rate constant for doxycycline degradation of 134.4 × 10−4 min−1, which is about 24.2 times higher than that of pristine BiO2−x under NIR irradiation.