Inspired by its unique porous structure, high value-added functional hydrogels combined with metal nanoparticles can lead to applications in different areas, including environmental catalysis. For this purpose, controlling the metal nanoparticle size is paramount. Herein, the porous lignocellulose hydrogel (LCG) with different lignin contents served as the matrix for in situ-synthesizing silver–lignin nanoparticles (Ag-L NPs), with lignin in the LCG as the reducing and capping agent of Ag-L NPs and the lignin content to control the size of Ag-L NPs. The well-dispersed lignin in the LCG network ensures immobilization and dispersion of Ag-L NPs. The particle size of Ag-L NPs is tailored by adjusting the lignin content (0.5, 6.5, 11.6, and 18.4%) of the LCG: the higher the lignin content, the smaller the Ag-L NPs. The smallest Ag-L NPs obtained were of 9.5 nm. The as-prepared Ag-L NPs/LCG composite samples showed outstanding catalytic reduction capability, with superior stability/reusability when applied for the catalytic reduction of 4-nitrophenol. Moreover, the Ag-L NPs/LCG composites exhibited high antibacterial activity, thus contributing to long-term storage stability.

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The synthesis of functional lignocellulosebased gels from sustainable biomass has received considerable attention in material chemistry. In this study, robust, porous, and lignin-containing lignocellulose hydrogels were prepared based on the sol−gel process. The lignin-containing lignocellulose materials were dissolved (or dispersed) in Nmethylmorpholine-N-oxide (NMMO) and cross-linked with a silane coupling agent 3-aminopropyltriethoxysilane (APTES), followed by coagulation and solvent exchange to form gel structures. The formation of Si−O−C cross-links among the lignocellulosic fibrils as a result of the addition of APTES was mainly responsible for the strength improvement. Furthermore, the presence of lignin also contributed to the enhancement of strength properties. The as-prepared lignocellulose gels were further characterized using rheological and compression tests. The dynamic storage modulus of APTES-reinforced lignocellulose gel (LCG A ) can reach up to 1391 kPa and the compressive modulus up to 96 kPa, which shows a 3-fold increase in viscoelastic properties and a 2-fold increase in compressive strength compared with unmodified gel. In addition, the obtained LCG A gel exhibits unique properties, such as antiultraviolet weathering and dye removal via adsorption, and their potential applications were explored.