Low loading Pt on TiO₂ for the ultra‐selective hydrogenation of chloronitrobenzenes to chloroanilines

Abstract

Low loading Pton TiO 2 were prepared by an impregnationreduction process for chemoselective hydrogenation of chloronitrobenzenes (CNBs) to chloroanilines (CANs). The structure and physicochemical properties were characterized by N 2 adsorption-desorption, X-ray diffraction, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy and temperature programmedreduction. The low loading Pt(� 0.08 wt %) on TiO 2 exhibited outstanding chemoselectivity for the catalytic hydrogenation of CNBs to CANs, without any disturbance on carbon-chlorine bond. The characterization data suggested that the Pt particles were highly dispersed on TiO 2 and strongelectronicinteractionsoccur between the dispersedPt andTiO 2 support, which led toelectron deficiency of nearly all Pt and production of suboxide TiO x species (x < 2) in the 0.08 wt % Pt/TiO 2 . The electron-deficient Pt and suboxide TiO x species favor N=O bondactivation, leading to its unique chemoselectivity.[a] M.

Regulating pore structures of carbon supports toward efficient selective hydrogenation of o-chloronitrobenzene on Pt nanoparticles

“…[12][13][14][15] To increase the utilization rate of the noble metals, the active metal phase is typically dispersed on suitable supports such as metal oxides (e.g., Al 2 O 3 , ZrO 2 and TiO 2 ), zeolites and porous carbons. [16][17][18][19][20][21][22] The textural properties and the surface chemical environments of the supports can affect the formation of metal nanoparticles, distribution and metal-support interactions. [23][24][25][26] Among them, carbonaceous materials are one of the most common carriers for loading noble metal nanoparticles due to their low-cost, chemical inertness and excellent wettability by some organic compounds.…”