Photon sintering-mediated green synthesis of jujube residue-derived Ag/graphene nanocomposites: Structural regulation for boosted catalysis and antibacterial activity

The high-value conversion of agricultural waste is a key strategy for green chemistry to mitigate resource depletion and environmental pollution. Silver-graphene nanocomposites, with excellent catalytic activity and structural stability, act as an ideal material system for efficient conversion and resource utilization of agricultural waste. Herein, bioactive components (α-helical protein fractions and triterpenoids) from jujube residue interact with Ag⁺ and graphene oxide through electrostatic interactions, π–π* conjugation, and bridging effects. Through photon sintering-mediated modification, morphologically controllable jujube residue-silver/reduced graphene oxide (j-Ag/rGO) nanocomposites were successfully fabricated. Under photon sintering conditions of 250 V and 40 ms, the as-prepared j-Ag/rGO showed superior antibacterial activity against Escherichia coli (minimum inhibitory concentration (MIC) = 25 μg/mL) and Staphylococcus aureus (MIC = 12.5 μg/mL). It also exhibits high catalytic performance for 4-nitrophenol reduction with a rate constant of 1.65 ± 0.02 min⁻¹ (R² = 0.999). Transmission electron microscopy three-dimensional reconstruction and computational simulations revealed the intrinsic regulation mechanism: Photon irradiation optimized Ag nanoparticle dispersion, induced lattice defects and single-crystal evolution, and strengthened Ag–rGO interfacial interactions, thereby exposing active sites, accelerating charge transfer, and enhancing antibacterial and catalytic properties. This work provides a low-cost and precisely tunable strategy for the recycling of agricultural waste and the development of multifunctional nanomaterials.