Graphite carbon nitride (g-C₃N₄) has been proven to have photocatalytic activity for NO-removal under visible-light irradiation. However, the competitive adsorption between NO and O₂ during the process may decrease the NO-removal activity of g-C₃N₄. In this study, N vacancies were constructed around Pd⁰ nanoparticles through the heat-island effect. The co-existence of N vacancies and Pd⁰ nanoparticles created a synergistic effect, which weakened the competitive adsorption between NO and O₂. Moreover, this synergistic effect improved the charge transfer and produced more hydroxyl radicals. As a result, the NO-removal activity of g-C₃N₄ was significantly improved. This study provided new insights into the design of photocatalysts used to remove gas pollutants through photocatalysis. Copyright © 2022 The Royal Society of Chemistry.