Amine-functionalized graphene nanosheet-supported PdAuNi alloy nanoparticles: efficient nanocatalyst for formic acid dehydrogenationElectronic supplementary information (ESI) available: Detailed information for NaOH trap experiments plus Fig. S1-S9 include information for the catalytic activity tests, control experiments, BFTEM images, GC chromatograms, FTIR analysis results, calculation methods and tables (PDF). See DOI: 10.1039/c8nj03117g

• Main Authors: Bulut, Ahmet, Yurderi, Mehmet, Kaya, Murat, Aydemir, Murat, Baysal, Akin, Durap, Feyyaz, Zahmakiran, Mehmet
• Format: Article
• Language: English
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c8nj03117g

Formic acid (HCOOH), a major by-product of biomass processing with high energy density, stability and non-toxicity, has a great potential as a safe and a convenient liquid hydrogen (H 2 ) storage material for combustion engines and fuel cell applications. However, high-purity hydrogen release from the catalytic decomposition of aqueous formic acid solution at desirable rates under mild conditions stands as a major challenge that needs to be solved for the practical use of formic acid in on-demand hydrogen generation systems. Described herein is a new nanocatalyst system comprised of 3-aminopropyltriethoxysilane-functionalized graphene nanosheet-supported PdAuNi alloy nanoparticles (PdAuNi/f-GNS), which can reproducibly be prepared by following double solvent method combined with liquid-phase chemical reduction, all at room temperature. PdAuNi/f-GNS selectively catalyzes the decomposition of aqueous formic acid through the dehydrogenation pathway (∼100% H 2 selectivity), in the absence of any promoting additives (alkali formates, Brønsted bases, Lewis bases, etc. ). PdAuNi/f-GNS nanocatalyst provides CO-free H 2 generation with a turnover frequency of 1090 mol H 2 mol metal −1 h −1 in the additive-free dehydrogenation of formic acid at almost complete conversion (≥92%) even at room temperature. The catalytic activity provided by PdAuNi/f-GNS nanocatalyst is higher than those obtained with the heterogeneous catalysts reported to date for the additive-free dehydrogenation of formic acid. Moreover, PdAuNi/f-GNS nanoparticles show high durability against sintering, clumping and leaching throughout the catalytic runs, so that the PdAuNi/f-GNS nanocatalyst retains almost its inherent catalytic activity and selectivity at the end of the 10th recycle. PdAuNi/f-GNS provides CO-free hydrogen generation from additive-free dehydrogenation of formic acid even at room temperature.