Activated carbon supported bimetallic catalysts with combined catalytic effects for aromatic nitro compounds hydrogenation under mild conditions

Activated Carbon Supported Non-noble Bimetallic Ni-Based Catalysts for Nitrocyclohexane Hydrogenation to Cyclohexanone Oxime under Mild Conditions

“…Moreover, it can be seen from Figure B that the Ni diffraction peak moves to a lower diffraction angle with the introduction of Cu, and the diffraction peaks at 44.0, 51.2, and 75.4° are ascribed to the (111), (200), and (220) crystal planes of the CuNi face-centered cubic (fcc) structure, respectively, indicating the formation of CuNi alloys. These results are confirmed by many researchers. ,− ,,, In addition, with the introduction of Cu, a diffraction peak appears at 43.3°, which is ascribed to the characteristic diffraction peak of Cu, and its peak intensity increases with the increment of Cu; the reason may be that the phase separation occurs when too much Cu is introduced …”

“…Figure shows the Ni 2p 3/2 XPS patterns of Ni/AC and bimetallic Cu-Ni/AC. As shown in Figure , Ni 2p 3/2 XPS spectra can be fitted into three components; the peaks around 853.1, 854.6, and 856.6 eV are attributed to Ni metal, Ni oxide (NiO), and Ni hydroxides (Ni­(OH) 2 and NiOOH), respectively. , Additionally, the peak at 861.7 eV is ascribed to the shake-up satellite, which is due to the multielectron excitation of high-valence nickel. , Noticeably, it can be observed from Figure b,c that the peak intensity of Ni metal increases with the introduction of a small amount of Cu (0.5 and 1 wt %), indicating that Cu can effectively promote NiO reduction and facilitate metal Ni exposure. ,, However, as can be seen in Figure d–g, the intensity of Ni 0+ decreases with the introduction of excessive Cu, and the reason may be that excessive Cu can promote the formation of larger metal oxide nanoparticles and NiO–CuO eutectic so as to inhibit NiO reduction . These results are in agreement with the H 2 -TPR results in Figure .…”

“…As shown in Figure a, compared with monometallic 20 wt % Ni/AC (24.6% NCH conversion and 49.1% selectivity to CHO), bimetallic catalysts show higher catalytic performance. The reason may be that the strong interaction between the metal promoter and Ni can effectively affect the size of metal active sites so as to significantly affect the catalytic activity. − Additionally, the XRD results in Figure S3B and TEM results in Figure show that the metal promoter can obviously reduce Ni nanoparticle agglomeration and sintering. Moreover, Pd-Ni/AC exhibits the highest catalytic hydrogenation activity (98.3% NCH conversion), but the selectivity to CHO is only 54.1%.…”

“…Non-noble metal nickel-based catalysts were widely used in the field of catalytic hydrogenation. − However, high-loading-amount monometallic nickel-based catalysts have problems of serious agglomeration and sintering, which seriously affect hydrogenation activity. Bimetallic nickel-based catalysts with other metal promoters showed that introduction of a metal promoter can effectively improve nickel dispersion and change the Ni species chemical environment. − Our previous studies have shown that a strong synergistic effect between copper and nickel leads to good nickel dispersion and large metal specific surface area so as to greatly improve the catalytic activity . Some other Fe-Ni, Pd-Ni, and Co-Ni bimetallic nickel-based catalysts were prepared and applied in hydrogenation and transfer hydrogenation processes. − Activated carbon is often used as a catalyst support because of its large specific surface area, high porosity, good electronic conductivity, and large chemical inertia …”

Combined Spectroscopic and Computational Study of Nitrobenzene Activation on Non-Noble Metals-Based Mono- and Bimetallic Catalysts

“…The high cost of noble metals has led to an important research effort to develop catalysts based on cheaper and more abundant non-noble metals [ 8 ]. In recent years, promising results have been reported with Co 3 O 4 and Fe 2 O 3 nanoparticles stabilized on carbon and N-doped carbon supports [ 22 , 23 , 24 ], as well as with mono- [ 25 , 26 , 27 , 28 , 29 , 30 ] and bimetallic [ 31 , 32 , 33 , 34 , 35 , 36 ] catalysts containing either atomically dispersed species or nanoparticles of Ni, Co, Cu, Fe or combinations of them, supported, in most cases, on carbon-containing materials. In contrast with the large number of publications reporting catalytic data, little attention has been paid to the reaction mechanism at the molecular level, and the macroscopic scheme proposed by Haber in 1898 [ 37 ] is still used to rationalize the catalytic results.…”