Graphene-oxide-supported CuAl and CoAl layered double hydroxides as enhanced catalysts for carbon-carbon coupling via Ullmann reaction

Abstract

Two efficient catalyst based on CuAl and CoAl layered double hydroxides (LDHs) supported on graphene oxide (GO) for the carbon-carbon coupling (Classic Ullmann Homocoupling Reaction) are reported. The pure and hybrid materials were synthesised by direct precipitation of the LDH nanoparticles onto GO, followed by a chemical, structural and physical characterization by electron microscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), surface area measurements, X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (TPR). The GO-supported and unsupported CuAl-LDH and CoAl-LDH hybrids were tested over the Classic Ullman Homocoupling Reaction of iodobenzene. In the current study CuAl-and CoAl-LDHs have shown excellent yields (91% and 98%, respectively) at very short reaction times (25 min). GO provides a light-weight, charge complementary and two-dimensional material that interacts effectively with the 2D LDHs, in turn enhancing the stability of LDH. As a result, the recyclability of the heterogeneous catalyst systems is greatly enhanced. After 5 re-use cycles, the catalytic activity of the LDH/GO hybrid is up to 2 times higher than for the unsupported LDH.

Incorporation of layered double nanomaterials in thin film nanocomposite nanofiltration membrane for magnesium sulphate removal

“…This characteristics properties were found as similar as shown by research reported from Dong and co-workers [11]. Besides that, the SEM images of LDH nanofillers shows that the CuAl LDH particles cluster all together as shown in red circle in figure 2 c) into a large aggregates mainly caused by high surface charge and surface tension [11,13].…”

Hydrogenation of Dicyclopentadiene Resin and Its Monomer over High Efficient CuNi Alloy Catalysts

“…This distortion is attributed to the Jahn‐Teller effect for Cu in an octahedral environment, which leads to long‐range disordering. It should be noted that the Cu 2 Al‐HTLCs hydrotalcite‐like compound shows an sharp and narrow diffraction peak, which exhibits identical pattern to that of the reference patterns for the Cu−Al hydrotalcite‐like compound (PDF 46–0099), suggesting that Cu 2 Al‐HTLCs hydrotalcite‐like precursor is also well prepared with the layered double hydrotalcite‐like‐type structure …”

Adsorption and anion exchange insight of indigo carmine onto CuAl-LDH/SWCNTs nanocomposite: kinetic, thermodynamic and isotherm analysis

“…These reections are the characteristics of LDH in like hydrotalcite phase. 27 The 33 The XPS spectrum of O 1s (Fig. 3d) shows a strong peak corresponding to the O-H bond of the carboxyl group on the SWCNT surface.…”