Selective non-oxidative dehydrogenation of ethanol to acetaldehyde and hydrogen on highly dilute NiCu alloys

Abstract

The non-oxidative dehydrogenation of ethanol to acetaldehyde has long been considered as an important method to produce acetaldehyde and clean hydrogen gas. Although monometallic Cu nanoparticles have high activity in the non-oxidative dehydrogenation of ethanol, they quickly deactivate due to sintering of Cu. Herein, we show that adding a small amount of Ni (Ni 0.01 Cu-Ni 0.001 Cu) into Cu to form highly dilute NiCu alloys dramatically increases the catalytic activity and increases their long-term stability. The kinetic studies show that the apparent activation energy decreases from ~70 kJ/mol over Cu to ~45 kJ/mol over the dilute NiCu alloys. The improved performance is observed both for nanoparticles and nanoporous NiCu alloys. The improvement in the long-term stability of the catalysts is attributed to the stabilization of Cu against sintering. Our characterization data show that Ni is atomically dispersed in Cu. The comparison of the catalytic performance of highly dilute alloy nanoparticles with nanoporous materials is useful to guide the design of novel mesoporous catalyst architectures for selective dehydrogenation reactions.

Production of acetic acid from ethanol over CuCr catalysts via dehydrogenation-(aldehyde–water shift) reaction

“…24 According to Colley, ethanol dissociated on the Cu component to form ethoxy species, and then ethoxy species were dehydrogenated to acetyl species. 25 Work by Jiang on the dehydrogenation of ethanol to ethyl acetate on CuCr catalyst proposed that the Cu 0 species played an important role in ethanol dehydrogenation to acetaldehyde, while the Lewis acidic site on Cr 2 O 3 phase might be responsible for the desorption of product ethyl acetate from CuCr catalyst's surface.…”

Microstructure and Crystallographic Determination of Nanoporous Catalysts.

“…The mechanism of morphology evolution has been investigated in details for single-phase solid solution precursor alloys such as the AuAg system [1,2]. But the dealloying mechanism is less understood for more complex intermetallic starting alloys where both crystal structure and lattice constant change dramatically during dealloying.Nanoporous copper (npCu) prepared by dealloying of CuZn alloys has recently been used as catalyst for ethanol hydrogenation [3]. In the present work, we studied the grain morphology of different CuZn alloys via Electron BackScatter Diffraction (EBSD) at different steps of the dealloying process.…”

“…Nanoporous copper (npCu) prepared by dealloying of CuZn alloys has recently been used as catalyst for ethanol hydrogenation [3]. In the present work, we studied the grain morphology of different CuZn alloys via Electron BackScatter Diffraction (EBSD) at different steps of the dealloying process.…”

Sample Preparation and Analysis of Aggregated ‘Single Atom Alloy’ Nanoparticles by Atom Probe Tomography

“…Our current research focuses on the use of nanostructured materials for sustainable catalysis applications, and more specifically, on metallic alloy catalyst materials for selective oxidation or dehydrogenation reaction. The principal design feature of the catalyst material is to combine a minor amount of active metal that facilitates creation of reactive intermediates with a less active majority phase that transforms these intermediates to desirable products with high selectivity.Copper-based catalysts, in the form of single atom alloy (SAA) catalysts, are currently being developed for selective dehydrogenation reactions using a modified electroless galvanic deposition method [2]. CuNi0.01 nanoparticles were synthesized on graphite to avoid the presence of a porous support which may affect the 3D reconstruction.…”

“…Copper-based catalysts, in the form of single atom alloy (SAA) catalysts, are currently being developed for selective dehydrogenation reactions using a modified electroless galvanic deposition method [2]. CuNi0.01 nanoparticles were synthesized on graphite to avoid the presence of a porous support which may affect the 3D reconstruction.…”