Dehydrogenation of bioethanol using Cu nanoparticles supported on N‐doped ordered mesoporous carbon

Abstract

Carbon supported Cu nanoparticles have a remarkable selectivity towards the catalytic dehydrogenation of bioethanol to acetaldehyde, which is an interesting alternative to the preparation from ethylene. In this work, we prepared a series of catalysts comprised of Cu nanoparticles supported on N-doped ordered mesoporous carbons to investigate the catalytic effect of nitrogen content. Our study shows that N-doping has a significant effect on the dispersion of Cu nanoparticles and that the highest content of N results in the highest activity. Furthermore, we show that the combined effects of strong metal-support interactions and nano-confinement is an effective method to prevent thermal and steam induced sintering. In contrast, we find no evidence that N-doping activates the substrate or change the rate-determining step. At 260°C, the best catalyst results in > 99 % selectivity and a site-time yield of 175 mol acetaldehyde /mol Cu /h. Under these conditions, the catalysts are stable for more than 12 h using an aqueous solution of 10 % ethanol as feed.

Efficient and Stable Cu‐Cu2O@NC Catalysts for Selective Catalytic Conversion of Glycerol to Lactic Acid

“…The N 2 adsorption‐desorption isotherms of Cu‐Cu x O@NC catalysts are shown in Figure 1. The type IV isotherms with H4 hysteresis loops indicate the existence of mesopores in the Cu‐Cu x O@NC‐400, Cu‐Cu x O@NC‐550 and Cu‐Cu x O@NC‐700 catalysts [27] . The BET specific surface areas of Cu‐Cu x O@NC‐400, Cu‐Cu x O@NC‐550 and Cu‐Cu x O@NC‐700 were determined to be 31 m 2 g −1 , 271 m 2 g −1 and 239 m 2 g −1 .…”

“…The peaks at around 952.2 eV and 932.3 eV for the Cu 2p spectra corresponding to Cu 2p 1/2 and Cu 2p 3/2 states are assigned to Cu 0 or Cu + [30] . There are no satellite peaks near the binding energy of 940 eV indicating the absence of Cu 2+ species on the surfaces of the Cu‐Cu x O@NC catalysts [27] . The Cu 2p 3/2 peak of the Cu‐Cu x O@NC‐700 catalyst shifts to a higher energy position than those of Cu‐Cu x O@NC‐400 and Cu‐Cu x O@NC‐550 catalysts, which might be due to the electron transfer from Cu to N. Figure 3(c) shows the Cu LMM Auger spectra of Cu‐Cu x O@NC catalysts.…”

Ethanol Dehydrogenation to Acetaldehyde over Co@N-Doped Carbon

“…As an alternative route, gaining significant interest, a number of studies have used catalysts based on readily available, inexpensive transition metals deposited on a lowacidity carrier. In line with that approach, activated carbon as itself [6][7][8][9][10][11], and much more successfully, carbon doped with MoO 3 or Cu, have shown high catalytic performances in the selective non-oxidative dehydrogenation of ethanol to acetaldehyde [12][13][14][15][16][17]. For example, conversion of ethanol over Cu deposited on activated carbon has attained a level of 65% with 96% selectivity to acetaldehyde at 350 • C under gas flow reaction conditions [15], while the use of Cu deposited on mesoporous carbon appeared even more effective, affording acetaldehyde in a 79% yield at 280 • C [13].…”

Metal and Metal Oxide Supported on Ordered Mesoporous Carbon as Heterogeneous Catalysts

“…This weakens the adsorption energy of the ORR intermediate species and increases the mass activity. , Sun and co-workers used N-doped mesoporous carbon (NMC) to support cobalt NPs to gain insight into the nature of the interfacial interaction and reveal the role of the electronic reconstruction by N-doping the carbon support in the sorption behavior of reactants . Additionally, N-doping can increase the metal–support interactions between the metals and carbon support and has a significant effect on the dispersion of metal NPs. − Electron paramagnetic resonance (EPR) spectra and X-ray photoelectron spectroscopy (XPS) show that sp 2 -type nitrogen in the carbonaceous framework functions as heterogeneous sites for the nucleation and growth of cobalt species . The interfacial interaction between cobalt oxide and N-doped mesoporous carbon involves electron transfer from the NMC to cobalt NPs, and the smaller cobalt particles seem to be more susceptible to the interfacial interaction than the larger ones.…”