2D Bismuth-Based Nanomaterials for Photocatalytic Nitrogen Oxide Removal: Progress and Prospects

Nitrogen oxides (NOx, similar to 95% NO) are significant atmospheric pollutants that contribute to environmental issues like acid rain and ozone layer depletion. The traditional remediation methods of physical/chemical adsorption and postcombustion reduction techniques fall short in effectively removing gaseous NO at parts per billion (ppb) levels. Consequently, photocatalysis for NO elimination has garnered intensive attention for its cost-effectiveness, efficiency, and ecofriendly attributes. Within the emerging nanomaterials for photocatalytic NO removal, 2D bismuth-based (Bi-based) photocatalysts are pivotal due to their distinctive electronic and structural characteristics. Nonetheless, a comprehensive review of the mechanisms and efficacy of NO removal via 2D Bi-based photocatalysts is still lacking. This review endeavors to fill that gap, elucidating the possible reaction pathways employed by 2D Bi-based nanomaterials for photocatalytic NO oxidation or reduction. Furthermore, it extends to highlight the main factors influencing their photocatalytic efficiencies and summarize three primary modification strategies for enhancement of the photocatalytic activities of 2D Bi-based nanomaterials, encompassing defect engineering, elemental doping, and the construction of heterojunctions. Finally, this review culminates with a forward-looking perspective in developing high-performance 2D Bi-based photocatalysts for NO removal, which underscores existing challenges and sparks new ideas for future work.