Metal-free graphitic carbon nitride (g-C₃N₄) should be an ideal candidate for photocatalytic degradation of pollutants. However, its performance is limited by low adsorption and high recombination rate of electron-hole pairs. Herein, g-C₃N₄ nanosheets were highly dispersed on rice husk carbon (CN@RHC) by one-step sealed calcination. The specific surface area was greatly increased from 7.7 to 137 m²/g, which improves the adsorption performance. Abundant dangling CC bond defects of rice husk carbon were confirmed by electron paramagnetic resonance, which played an important role of electron acceptor and effectively inhibit the recombination of photogenerated carriers. As a result, 98% of Methylene blue was removed in 4.5 h using a 5 W light emitting diode source with visible light while only 80% of that was removed by bulk g-C₃N₄. The degradation performance was enhanced by the synergism of excellent adsorption performance and better photogenerated carriers transport performance. Based on the simple synthesis method, low cost and excellent visible photocatalytic performance, dangling CC bonds should be the focus for promoting photocatalysis as well as improve the added value of agricultural waste.

无金属石墨碳氮化物（gC ₃ N ₄）应该是污染物光催化降解的理想选择。然而，其性能受到电子-空穴对的低吸附和高复合率的限制。在此，通过一步密封煅烧将gC ₃ N ₄纳米片高度分散在稻壳碳（CN @ RHC）上。比表面积从7.7增加到137 m ²/ g，这提高了吸附性能。电子顺磁共振证实了稻壳碳的大量悬空CC键缺陷，这在电子受体中起着重要作用，并有效地抑制了光生载流子的重组。结果，使用具有可见光的5 W发光二极管源在4.5小时内去除了98％的亚甲蓝，而整体gC ₃ N ₄仅去除了80％的亚甲基蓝。。优异的吸附性能和更好的光生载流子传输性能的协同作用增强了降解性能。基于简单的合成方法，低成本和优异的可见光催化性能，悬挂的CC键应成为促进光催化并提高农业废物附加值的重点。