Heteropoly blue-modified ultrathin bismuth oxychloride nanosheets with oxygen vacancies for efficient photocatalytic nitrogen fixation in pure water

• Published in: Journal of colloid and interface science 2025-01, Vol.677 (Pt A), p.610-619
• Main Authors: Sun, Mingliang, Zhang, Ruyu, Sun, Ao, Jia, Xiaowei, Liu, Xianchun, Yu, Xiaodan, Xing, Yan
• Format: Article
• Language: English
• Subjects: absorption; adsorption; ammonia; bismuth; Bismuth oxychloride; Fourier transform infrared spectroscopy; Heterojunction; Heteropoly blue; lighting; nanoparticles; nanosheets; nitrogen; nitrogen fixation; oxygen; Oxygen vacancy; photocatalysis; photocatalysts; Photocatalytic nitrogen reduction; sustainable technology
• ISSN: 0021-9797; 1095-7103; 1095-7103
• DOI: 10.1016/j.jcis.2024.07.234

In this work, xr-PW12/BiOCl-OVs heterojunction composites have been prepared by loading of heteropoly blue (r-PW12) NPs on the surface of ultrathin BiOCl nanosheets with oxygen vacancies, which exhibits an excellent photocatalytic N2 fixation performance in pure water. The superior N2 fixation performance is attributed to the synergistic effect of oxygen vacancies coupled with heterojunction construction. [Display omitted] Photocatalytic nitrogen reduction is a promising green technology for ammonia synthesis under mild conditions. However, the poor charge transfer efficiency and weak N2 adsorption/activation capability severely hamper the ammonia production efficiency. In this work, heteropoly blue (r-PW12) nanoparticles are loaded on the surface of ultrathin bismuth oxychloride nanosheets with oxygen vacancies (BiOCl-OVs) by electrostatic self-assembly method, and a series of xr-PW12/BiOCl-OVs heterojunction composites have been prepared. Acting as a robust support, ultrathin two-dimensional (2D) structure of BiOCl-OVs inhibits the aggregation of r-PW12 nanoparticles, enhancing the interfacial contact between r-PW12 and BiOCl. More importantly, the existence of oxygen vacancies (OVs) provides abundant active sites for efficient N2 adsorption and activation. In combination of the enhanced light absorption and promoted photogenerated carriers separation of xr-PW12/BiOCl-OVs heterojunction, under simulated solar light, the optimal 7r-PW12/BiOCl-OVs exhibits an excellent photocatalytic N2 fixation rate of 33.53 µmol g-1h−1 in pure water, without the need of sacrificial agents and co-catalysts. The reaction dynamics is also monitored by in situ FT-IR spectroscopy, and an associative distal pathway is identified. Our study demonstrates that construction of heteropoly blues-based heterojunction is a promising strategy for developing high-performance N2 reduction photocatalysts. It is anticipated that combining of different defects with heteropoly blues of different structures might provide more possibilities for designing highly efficient photocatalysis systems.