Pd–N coordination on nitrogen-deficient g-C3N4/alumina foam enables selective visible-light NO oxidation with suppressed NO2 formation
Year: 2026
Type: article
Abstract: Nitrogen oxides (NO x ) are significant contributors to atmospheric pollution and pose serious threats to human respiratory and cardiovascular health, necessitating the development of reliable remediation technologies. Graphitic carbon nitride (g-C 3 N 4 ) has emerged as a promising solar-light-responsive photocatalyst for ambient NO purification; however, its practical application is hindered by rapid charge recombination and limited visible-light utilization. Additionally, powdery g-C 3 N 4 experiences severe aggregation, material shedding, and non-uniform light harvesting during gaseous NO degradation, which greatly restricts its real-world applicability. To address these limitations, this study developed a monolithic nitrogen-vacancy-modified g-C 3 N 4 -supported palladium (Pd) catalyst (CNN-Pd), which features a Pd–N coordination environment and is anchored on Al 2 O 3 foam ceramics for visible-light-assisted NO oxidation. Leveraging the synergy between nitrogen vacancies and multivalent Pd sites, the CNN-Pd composite achieves a remarkable visible-light-driven NO removal efficiency of 75.9%. Importantly, the selectivity for the undesired NO 2 byproduct is minimized to only 9.8%, corresponding to a relative reduction of approximately 62% compared to pristine CN (25.8%). Characterizations, including X-ray photoelectron spectroscopy, electron paramagnetic resonance, and UV–vis diffuse reflectance spectroscopy, confirm the coexistence of nitrogen vacancies and mixed-valence Pd (Pd + , Pd 2+ ). The nitrogen vacancies create mid-gap defect levels that narrow the bandgap and enhance oxygen adsorption, while the Pd–N coordination provides abundant transfer channels for trapping photogenerated electrons. These dual functional units work synergistically to accelerate the generation of reactive oxygen species, drive the complete oxidation of NO into nitrate, and significantly reduce the formation of toxic NO 2 .
Source: Materials Today Catalysis
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,080
OpenAlex ID: W7223098562