Nanoalloys (NAs), which are distinctly different from bulk alloys or single metals, take on intrinsic features including tunable components and ratios, variable constructions, reconfigurable electronic structures, and optimizable performances, which endow NAs with fascinating prospects in the catalysis field. Here, the focus is on NA materials for chemical catalysis (except photocatalysis or electrocatalysis). In terms of composition, NA systems are divided into three groups, noble metal, base metal, and noble/base metal mixed NAs. Their design and fabrication for the optimization of catalytic performance are systematically summarized. Additionally, the correlations between the composition/structure and catalytic properties are also mentioned. Lastly, the challenges faced in current research are discussed, and further pathways toward their development are suggested.

heterostructured Ni/ graphene nanocomposites were constructed via electrostaticinduced spread by following in situ-reduction growth process for magnetically recyclable catalysis of p-nitrophenol to paminophenol. The heterostructures with large 2D surface and moderate inflexibility enable the superior catalytic activity and selectivity toward hydrogenation reaction for p-nitrophenol. On the basis of high-efficiency utilization of Ni Nps catalysis activity and electron-enhanced effect from graphene, the coupling effect of Ni/graphene magnetic nanocomposites can lead to highly catalytic activity for the hydrogenation reaction of p-nitrophenol with the pseudo-first-order rate constants of 11.7 × 10 −3 s −1 , which is over 2-fold compared to Ni Nps (5.45 × 10 −3 s −1 ) and higher than reported noble metal nanocomposites. Complete conversion of p-nitrophenol was achieved with selectivity to p-aminophenol as high as 90% under atmosphere and room temperature. Additionally, this heterostructured magnetic nanocatalyst can be efficiently recycled with long lifetime and stability over 10 successive cycles. This work displayed the value of non-noble metal/graphene nanocomposites in catalysts development for green chemistry.

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Nowadays, it is of great significance and a challenge to design a noble-metal-free catalyst with high activity and a long lifetime for the reduction of aromatic nitro-compounds. Here, a 2D structured nanocomposite catalyst with graphene supported CuNi alloy nanoparticles (NPs) is prepared, and is promising for meeting the requirements of green chemistry. In this graphene/CuNi nanocomposite, the ultra-small CuNi nanoparticles (∼2 nm) are evenly anchored on graphene sheets, which is not only a breakthrough in the structures, but also brings about an outstanding performance in activity and stability. Combined with a precise optimization of the alloy ratios, the reaction rate constant of graphene/Cu61Ni39 reached a high level of 0.13685 s(-1), with a desirable selectivity as high as 99% for various aromatic nitro-compounds. What's more, the catalyst exhibited a unprecedented long lifetime because it could be recycled over 25 times without obvious performance decay or even a morphology change. This work showed the promise and great potential of noble-metal-free catalysts in green chemistry.

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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.