Interfacial Phenomenon and Nanostructural Enhancements in Palladium Loaded Lanthanum Hydroxide Nanorods for Heterogeneous Catalytic Applications.

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.