Abstract
Hydrogenation and cross-coupling reactions are of great importance for industrial applications and noble metal based catalysts are filling the void since the last few decades. However, the high cost of noble metals and poor recycling performance provides an opportunity for chemists to look for alternate options. Herein, we present the use of Lanthanum hydroxide as support for loading ultra-low amount of Pd for hydrogenation and cross-coupling reactions. Lanthanum hydroxide having controlled morphologies comprises exposed crystallographic facets which interact with small sized Pd NPs and shows versatile and effective catalytic performance. The reduction of 4-NP over Pd/La(OH)3 was achieved within very short time (45s) with a rate constant of 60 × 10−3 s−1. The hydrogenation of styrene was also accomplished within 1 hour with much high TOF value (3260 h−1). Moreover, the Suzuki cross-couplings of iodobenzene and phenyl boronic acid into biphenyl completed within 35 min with a TOF value of 389 h−1. The strong interfacial electronic communication regulates electron density of catalytic sites and lowers energy for adsorption of reactant and subsequently conversion into products. Moreover, abundant hydroxyl groups on the surface of La(OH)3, large surface area, mono-dispersity and ultra-small size of Pd NPs also favors the efficient conversion of reactants.
Highlights
Recent years have witnessed considerable interest of rare earth oxides and hydroxides in catalysis[10,11] luminescent devices, communication[12] time resolved fluorescence (TRF) labels for biological detection[13,14] and many others applications on account of their unique optical, electronic, magnetic and chemical properties arising from their 4 f electrons[15,16,17]
The abundant hydroxyl groups on lanthanum hydroxide offers plenty of anchoring sites for Pd ion and subsequently immobilizing Pd NPs resulting in the confinement of NPs and minimizing aggregation
The high-resolution TEM (HRTEM) image reveals Pd nanoparticles loaded onto the surface of La(OH)[3] with observed lattice spacing value of 0.22 nm ascribed to the [111] plane of Pd
Summary
Hydrogenation and cross-coupling reactions are of great importance for industrial applications and noble metal based catalysts are filling the void since the last few decades. We present the use of Lanthanum hydroxide as support for loading ultralow amount of Pd for hydrogenation and cross-coupling reactions. Lanthanum hydroxide having controlled morphologies comprises exposed crystallographic facets which interact with small sized Pd NPs and shows versatile and effective catalytic performance. The selectivity and sensitivity of reactions can be enhanced through the use of electrostatics interactions, regulating electron density of catalytic sites and controlling the size of metal nanoparticles. We present a unique strategy for the synthesis of strongly coupled Pd NPs with lanthanum hydroxide rods for the reduction of 4-nitrophenol into 4-aminophenol, hydrogenation of styrene and Suzuki cross-coupling reactions[27]. The as synthesized hexagonal La(OH)[3] rods have highly isotropic structure along the c-axis and interacts with the planes of Pd resulting in exposed catalytic centers for hydrogenation and cross coupling reactions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
