Leveraging rGO/g-C3N4 composite for enhanced rice plant (Oryza sativa) tolerance to lead phytotoxicity and photocatalytic dye degradation

• The rGO/g-C3N4 nanohybrid significantly mitigates lead-induced stress in rice, enhancing both plant growth and physiological health. • It also exhibits superior visible-light-driven photocatalytic performance for dye degradation, thereby offering an effective method for water purification. • Overall, rGO/g-C3N4 presents a promising, multifaceted solution for improving crop productivity in contaminated soils and promoting sustainable environmental remediation. Heavy metal contamination, particularly lead (Pb), poses an escalating risk to agricultural sustainability. Fertiliser is expected to improve nutrient use while preventing heavy metal contamination. Nanomaterials have shown remarkable potential in mitigating heavy metal stress in plants. The rGO/g-C 3 N 4 composite was synthesized to mitigate Pb toxicity in rice cultivation and then used as a photocatalyst in the degradation of organic dyes such as methylene blue (MB) to better use materials when they are released in nature. Bulk g-C 3 N 4 formed via urea pyrolysis was integrated with rGO synthesized via a modified Hummers method. The characterization using XRD, Raman, FTIR, SEM, UV-Vis DRS, and PL confirmed rGO incorporation, thus supporting its use to improve the plant phytotoxicity and photocatalytic activity. Hydroponic rice studies indicated reduced Pb uptake, diminished oxidative stress, and elevated Chlorophyll, resulting in increased biomass. to the Pb‐only group. The addition of composite helps to alleviate the effects of Pb exposure, proven by the improvement in root and leaf length up to 15–20% and decreasing MDA level from 0.64 to 0.48 μM/mg protein compared the plant without composite. Under visible light, rGO/g-C 3 N 4 showed higher MB degradation (68%) than g-C 3 N 4 alone (50%). The kinetic studies of MB photodegradation followed the pseudo-first-order Lagergren model with a kinetic constant of 0.3023 g mg −1 min −1 . Thus, rGO/g-C 3 N 4 is a promising material for sustainable agriculture and environmental remediation, offering versatile and beneficial outcomes.