Assembly of Core−Shell Structures for Photocatalytic Hydrogen Evolution from Aqueous Methanol

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• 作者：Han Zhou ; Erwin M. Sabio ; Troy K. Townsend ; Tongxiang Fan ; Di Zhang ; Frank E. Osterloh
• 刊名：Chemistry of Materials
• 出版年：2010
• 出版时间：June 8, 2010
• 年：2010
• 卷：22
• 期：11
• 页码：3362-3368
• 全文大小：870K
• 年卷期：v.22,no.11(June 8, 2010)
• ISSN：1520-5002

文摘

We present a layer-by-layer assembly approach for the construction of core−shell structures with photocatalytic activity for hydrogen evolution from aqueous methanol. Submicrometer silica spheres and ultrasonicated (TBA, H)Ca₂Nb₃O₁₀ and PA₂K₂Nb₆O₁₇ nanosheets are used as the building blocks to assemble core−shell structures with single and double (homostacked and heterostacked) nanosheet layers via sequential electrostatic coupling with poly(diallyldimethylammonium) chloride (PDDA). The lateral nanosheet distribution on the SiO₂ spheres is observed with SEM while the stacking is directly observed with TEM. Diffuse reflectance UV/vis spectra reveal the nanosheet absorbance edge at 350 nm. All core−shell structures are active for photocatalytic H₂ evolution from aqueous methanol solution with gas evolution rates comparable or smaller than observed for individually dispersed nanosheets. Heterostacks were more active than homostacks, with the latter being comparable to single layers (at equal mass). Loading with Pt nanoparticles increases H₂ evolution rates, but reduces the activity differences between homostacked and heterostacked samples.