Non-Noble Metal Ni Nanoparticles Supported on Highly Dispersed TiO₂-Modified Activated Carbon as an Efficient and Recyclable Catalyst for the Hydrogenation of Halogenated Aromatic Nitro Compounds under Mild Conditions

Abstract

TiO2-modified oxygen-functionalized activated carbon (TiO2@OAC)-loaded nickel-based catalysts (Ni/TiO2@OAC) were synthesized and applied in the hydrogenation of chloronitrobenzene (CNB) to chloroanilines (CANs). The characterization results indicate that introduction of TiO2 restrains nickel nanoparticles sintering and improves the stability of the catalysts by strong metal–support interaction. Additionally, the X-ray photoelectron spectroscopy results suggest that the electron donating effect of Ti3+ produces electron-rich Ni (Niδ−), which inhibits C–Cl moiety adsorption. The formed Niδ− species might induce electron-rich hydrogen (H–) generation which facilitates a nucleophilic attack on −NO2 rather than an electrophilic attack on the C–Cl bond. Furthermore, the electron-donating ability of −NH2 could be reduced because of the interaction between −OH in TiO2@OAC and −NH2 in CAN. Hence, the dechlorination is inhibited and the selectivity to m-CAN is up to 99.0%. The catalytic performance of Ni/TiO2@OAC could be maintained after five cycles.

ZIF-Derived Co-Based Catalysts for Efficient Hydrogenation of Aromatic Compounds: the Study of the Co–Nx Active Sites

“…These results could be emerged more clearly by Mulliken analysis (the enlarged views on the right of Figure ). The H 2 dissociation went through a heterolytic cleavage on both of Co@NC and Co@C models. ,, The H + on the nitrogen species possesses more positive charge on Co@NC than the H + on the carbon species of Co@C, while the H – on the cobalt species on the Co@NC shows less negative charge than that on the Co@C. It seems like that the nitrogen species affect the whole electron circumstance due to its electron pair, and there was electron transport between hydrogen, nitrogen, and cobalt on the surface of the catalysts, which lead to the heterolytic dissociation of H 2 . Thus, the Co–N x species in the catalyst are more likely to be the active sites during the H 2 dissociation in the hydrogenation reaction.…”

Transition Metal Oxide-Modified Ir Nanoparticles Supported on SBA-15 Silica for Selective Hydrogenation of Substituted Nitroaromatics

“…Typically, various strategies, such as support properties, − alloy effects, − and strong metal–support interactions (SMSI), , have been proposed to enhance the selectivity of metal catalysts. Among them, creating strong metal–support interaction is one of the main strategies to change the selectivity of a reaction.…”

“…For example, a Pd/Al 2 O 3 catalyst for selective hydrogenation of p-chloronitrobenzene gave low selectivity to p-chloroaniline (45.8%), 7 and a single Pt catalyst suffered from serious side reactions for selective hydrogenation of 3-nitrostyrene to 3vinylaniline. 8 Typically, various strategies, such as support properties, 9−11 alloy effects, 12−14 and strong metal−support interactions (SMSI), 15,16 have been proposed to enhance the selectivity of metal catalysts. Among them, creating strong metal−support interaction is one of the main strategies to change the selectivity of a reaction.…”

Prolonged-Photoresponse-Lifetime Ni2P Nanocrystalline with Highly Exposed (001) for Efficient Photoelectrocatalytic Hydrogen Evolution

“…4,5 The tunable band gaps, light substance interaction, strong electron confinement, and superior immunity to short channel effects result in unique advantages in catalytic reactions. 6,7 The transitional-metal phosphides (TMPs) have been considered as a new type of catalysts in fields of hydroprocessing, 8 hydrogenation of nitro-compounds, 9 and photocatalytic degradation of organic contaminants. 10 Among TMPs, nickel phosphide (Ni 2 P) exhibited more remarkable catalytic activity and stability toward the hydrogen or oxygen evolution reactions.…”

“…The photoelectrochemical (PEC) water splitting technique was considered as a combination of electrocatalysis and photocatalysis and thus possesses many virtues. − Myriad semiconductor nano-materials have been explored as photoelectrocatalysts. , The tunable band gaps, light substance interaction, strong electron confinement, and superior immunity to short channel effects result in unique advantages in catalytic reactions. , The transitional-metal phosphides (TMPs) have been considered as a new type of catalysts in fields of hydroprocessing, hydrogenation of nitro-compounds, and photocatalytic degradation of organic contaminants . Among TMPs, nickel phosphide (Ni 2 P) exhibited more remarkable catalytic activity and stability toward the hydrogen or oxygen evolution reactions. , In TMPs, atoms of phosphorus (P) were assumed to be doped into metal lattices.…”