Adsorption and Decomposition of Ethanol on Cu₂O(111) and (100)

Abstract

Ethanol dehydrogenation on metal oxides such as Cu2O is an important reaction for the production of renewable energy by fuel cells both via the production of H2 fuel and via application in direct alcohol fuel cells. To better understand this reaction, we studied the adsorption, dissociation, and desorption of ethanol on Cu2O­(111) and (100) surfaces using high-resolution photoelectron spectroscopy, vibrational sum-frequency generation spectroscopy, and temperature-programmed desorption accompanied by density functional theory calculations. On Cu2(100), the first layer consists primarily of dissociatively adsorbed ethoxy. Second and third layers of ethanol physisorb at low temperatures and desorb below 200 K. On the Cu2O­(111) surface, adsorption is mixed as ethoxy, ethanol, and the products following C–C cleavage, CH x , and OCH x , are found in the first layer. Upon heating, products following both C–C and C–O bond breaking are observed on both surfaces and continued heating accentuates molecular cracking. C–O cleavage occurs more on the (100) surface, whereas on the Cu2O­(111) surface, C–C cleavage dominates and occurs at lower temperatures than those for the (100) surface. The increased ability of Cu2O­(111) to crack ethanol is explained by the varied surface structure including surface oxygen, electron-rich O vacancies, and Cu.

Investigation on Cu2O Surface Reconstruction and Catalytic Performance of NH3-SCO by Experimental and DFT Studies

“…The effects of onsite Coulomb interactions of the localized d orbital and exchange interactions for copper oxides were considered by employing the PBE + U method. The Hubbard parameter of U – J was set to 3.6 eV based on that reported in the literature, − which was determined from the electrostatically embedded Hartree–Fock calculations using the method exploited by Mosey and co-workers . Atomic structural optimization was relaxed using the damped molecular dynamics method until the force difference between the two steps was ≤0.02 eV/Å, and a Gaussian smearing of σ = 0.2 eV was applied to accelerate the convergence.…”

Synthesis of Catalytic Ni/Cu Nanoparticles from Simulated Wastewater on Li–Al Mixed Metal Oxides for a Two-Stage Catalytic Process in Ethanol Steam Reforming: Catalytic Performance and Coke Properties

“…Copper is known to be an effective catalyst of ethanol dehydrogenation (Equation ( 2)) [11]. The participation of Cu 2 O in ethanol dehydrogenation (Equation (2)) has also been examined [37]. Sato et al [38] suggested that the Cu + /Cu 0 pairs on a Cu-based catalyst (Cu/SiO 2 ) exhibited high selectivity toward acetaldehyde in ethanol conversion reaction.…”

Position of Gold Dictates the Photophysical and Photocatalytic Properties of Cu2O in Cu2O/Au Multicomponent Nanoparticles

“…an enhanced activity increasing from {100} to {111} facets associated with cubic and octahedral morphologies, respectively, was reported. [1] Moreover, surface energies, [7] binding of solvent molecules (most importantly ethanol molecules) [8,9] as well as the deposition of noble metals on the different crystal planes also show facet-dependent characteristics. [7,10,11] Hence, tailoring the morphology of the nanoparticle has opened up new routes towards the synthesis and design of Cu2O-based multicomponent (photo)catalysts.…”