High photocatalytic activity of Cu2O embedded in hierarchically hollow SiO2 for efficient chemoselective hydrogenation of nitroarenes

Abstract

Photocatalytic organic conversion is a crucial process in the hydrogenation of nitroarenes, but harsh reaction conditions such as long reaction time, high hydrogen pressure, and organic medium still need to be considerably overcome under visible-light irradiation. Here, we have constructed a transition metal oxide photocatalyst by embedding low-cost Cu2O with strong visible-light absorption into hierarchically hollow SiO2 sphere (SiO2-Cu2O@SiO2) that can suppress the escape of photogenerated atomic hydrogen and promote the contact probability between hydrogen atom and nitroarene molecules due to confinement effect.Remarkably, the SiO2-Cu2O@SiO2 photocatalyst can exhibit efficient chemoselectivity toward the hydrogenation of various nitroarenes in an aqueous system at ambient conditions, successfully working out the requirement of strict hydrogenation conditions, especially for organic medium over almost all of the reported photocatalysts. Notably, quantitative aniline can be produced for the visible-light catalytic reduction of nitroarenes, suggesting a considerable potential for industrial applications.

Simple, controllable and environmentally friendly synthesis of FeCoNiCuZn-based high-entropy alloy (HEA) catalysts, and their surface dynamics during nitrobenzene hydrogenation

“…For applied potential more negative than − 0.5 V (η = 0 V for hydrogen reduction), the current sharply increased, which can be attributed to the irreversible reduction of nitrobenzene involving hydrogen transfer. A similar behavior was observed for Cu electrodes [48][49][50], thus we can assume that Cu sites actively participate in the nitrobenzene hydrogenation process either by acting as the adsorption site or by providing the adsorbed hydrogen species required for the hydrogenation process.…”

“…Among these, electrocatalysis is the least studied and the one presenting more difficulties, especially regarding the conversion yields, selectivity, stability of the materials and scalability. A variety of materials and methods have been used to overcome these problems, and the best results have been obtained using copper (Cu) and its alloys [48,49], or alloys with noble metals (Pt, Pd) [50] in different morphologies. These electrocatalysts provide relatively large potential window and slow hydrogen evolution kinetics.…”

Fractal growth of a fern-like nanostructured Cu2O film electrode for electrochemical reduction of CO2 to ethanol

“…54,55 There is a strong Auger peak in the region 562 to 790 eV related to the Cu 2 O phase conrming the growth of Cu 2 O rather than metallic Cu that shows the Auger peak at relatively lower binding energy. [55][56][57][58][59] The Cu 2p core level spectra of CuP3T5, CuP4T5 and CuP5T5 samples are shown in Fig. 4d-f, respectively.…”

Embedding of copper(i) oxide quantum dots in MOF-801 for the photocatalytic degradation of acid yellow 23 under visible light

“…2(B) shows the high resolution XPS spectrum of the Cu 2p peak of Cu 2 OQDs@MOF-801 where Cu 2p 3/2 and Cu 2p 1/2 peaks are located at 933.66 and 953.62 eV, respectively, suggesting the Cu 1+ oxidation state and confirms the formation of the Cu 2 O into Cu 2 OQDs@MOF-801 nanocomposite, which is in close agreement with the previously reported data. 57…”