Treating wood with nanoparticles requires that a nanoparticle suspension can infiltrate the wood; alternatively nanoparticles can be formed within the wood. We used tetraethoxysilane (TEOS) to form silica particles within wood. TEOS hydrolyses to form silica and ethanol in the presence of water and a base (such as ammonia). The wood should be dried under vacuum to allow permeation of a TEOS solution into the structure, whereby silica is formed in situ. I have termed the silica as a nanoparticle though this is not necessarily so as the silica formation is constrained by the porous cavities within wood that may be of micrometer size. We used this method with delignified wood, where the wood only contained the cellulose microstructure without the adhesive contribution of lignin. We then added epoxy resin as a new binder, and as a variant we removed the cellulose by pyrolysis leaving a silica framework to which we added epoxy to form a wood replicate microstructure within a silica–epoxy composite.

Reference: Daud, N. and R. Shanks (2014), Epoxy–silica composites replicating wood cell structure, Composites Part A: Applied Science and Manufacturing 62: 11-15.

Tarek M. Abou Elmaaty Are you trying to make a relatively cheap product (wood) more expensive by adding a very expensive component (nanoparticles)?

Soak the wood in a solution of chloroauric acid and reduce with hydrogen or a 5% hydrazine hydrate solution.

Treating wood with nanoparticles requires that a nanoparticle suspension can infiltrate the wood; alternatively nanoparticles can be formed within the wood. We used tetraethoxysilane (TEOS) to form silica particles within wood. TEOS hydrolyses to form silica and ethanol in the presence of water and a base (such as ammonia). The wood should be dried under vacuum to allow permeation of a TEOS solution into the structure, whereby silica is formed in situ. I have termed the silica as a nanoparticle though this is not necessarily so as the silica formation is constrained by the porous cavities within wood that may be of micrometer size. We used this method with delignified wood, where the wood only contained the cellulose microstructure without the adhesive contribution of lignin. We then added epoxy resin as a new binder, and as a variant we removed the cellulose by pyrolysis leaving a silica framework to which we added epoxy to form a wood replicate microstructure within a silica–epoxy composite.

Reference: Daud, N. and R. Shanks (2014), Epoxy–silica composites replicating wood cell structure, Composites Part A: Applied Science and Manufacturing 62: 11-15.

Interesting. May I know the application? As I experienced, HAuCl4 can damage the surface of wood. Its strong monoprotic acid.