Preparation and reactivity of UV light-reduced Pd/α-Fe2O3 catalyst towards the hydrogenation of o-chloronitrobenzene

• Pd/α-Fe2O3 catalyst was prepared by a convenient UV light-induced reduction.
• Pd/α-Fe2O3 maintained good reactivity towards o-CNB hydrogenation at high o-CNB/Pd ratios up to 7000.
• Pd/α-Fe2O3-promoted o-CNB hydrogenation gave 100% o-CNB conversion and 91.4% o-CAN selectivity under mild conditions.

A type of Pd/α-Fe2O3 catalyst was synthesized by a convenient UV light-induced reduction in the presence of Fe3+ ions. The synthesized Pd/α-Fe2O3 particles were characterized by X-ray diffraction (XRD), low-resolution transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectrum (XPS), atomic force microscope (AFM), scan electron microscopy with energy dispersion spectra (SEM-EDS), FT-IR and BET. Related characterizations confirm that UV light-induced reduction is a feasible, simply and environment-friendly method for the preparation of supported catalysts containing active metal. Furthermore, hydrogenation of o-chloronitrobenzene (o-CNB) to o-chloroaniline (o-CAN) by the selected Pd(0.5%)/α-Fe2O3 was investigated systematically. The α-Fe2O3-supported Pd catalyst was found to exhibit good catalytic activity and selectivity for the o-CNB reduction under mild conditions. The hydrogenation of o-CNB over the resulting Pd-based catalyst gave a 100% o-CNB conversion and 91.4% selectivity of o-CAN under the reaction conditions of 50 °C, 2 h, 1 MPa hydrogen pressure, no-CNB/nPd = 6000:1. Moreover, the resulting Pd-based catalyst remained higher hydrogenation reactivity after three runs even if a sharply decrease in activity was observed at the fourth run. The obtained results reveal the as-prepared Pd/α-Fe2O3 is an efficient catalyst for the hydrogenation of o-CNB even at a high level of substrate concentration.

The present work reported the convenient preparation of Pd-based catalyst over α-Fe2O3 as support via a UV light-induced reduction process. The resulting Pd/α-Fe2O3 catalyst exhibited good performance for the hydrogenation reduction of o-chloronitrobenzene (o-CNB), yielding completely o-CNB conversion and 91.4% selectivity of o-CAN at high substrate/catalyst ratio (6000:1) under mild conditions.Figure optionsDownload high-quality image (206 K)Download as PowerPoint slide