High-density platinum nanoparticle-decorated titanium dioxide nanofiber networks for efficient capillary photocatalytic hydrogen generation

Aldehyde-functionalized cellulose nanofibers (CNFs) were applied to synthesize Pt nanoparticles (NPs) on CNF surfaces via on-site Pt ion reduction and achieve high concentration and uniform Pt NP loading. ALD could then selectively deposit TiO2 on CNFs and keep the Pt NPs uncovered due to their drastically different hydro-affinity properties. The high-temperature ALD process also simultaneously improved the crystallinity of Pt NPs and decomposed the CNF template leaving a pure anatase phase TiO2 nanofiber network decorated with high-density Pt NPs (up to 11.05 wt%). The as-prepared fibrous Pt-TiO2 network photocatalyst was integrated with CNF strips to develop a capillary setup for photocatalyzed hydrogen generation. Better reaction kinetics and higher efficiency were achieved from the capillary design compared to conventional in-electrolyte reactions. The initial H-2 generation rates were 100.56-138.69 mmol g(-1) h(-1) from the capillary setup based on different Pt NP loadings, which were 123.3-288.6% larger than those of the in-electrolyte setup (25.88-62.11 mmol g(-1) h(-1)). This 3D nanofibrous Pt-TiO2 capillary photocatalyst offers a brand new solution for improving the throughput of photocatalytic hydrogen production.