Highly-efficient RuNi single-atom alloy catalysts toward chemoselective hydrogenation of nitroarenes

Abstract

The design and exploitation of high-performance catalysts have gained considerable attention in selective hydrogenation reactions, but remain a huge challenge. Herein, we report a RuNi single atom alloy (SAA) in which Ru single atoms are anchored onto Ni nanoparticle surface via Ru–Ni coordination accompanied with electron transfer from sub-surface Ni to Ru. The optimal catalyst 0.4% RuNi SAA exhibits simultaneously improved activity (TOF value: 4293 h–1) and chemoselectivity toward selective hydrogenation of 4-nitrostyrene to 4-aminostyrene (yield: >99%), which is, to the best of our knowledge, the highest level compared with reported heterogeneous catalysts. In situ experiments and theoretical calculations reveal that the Ru–Ni interfacial sites as intrinsic active centers facilitate the preferential cleavage of N–O bond with a decreased energy barrier by 0.28 eV. In addition, the Ru–Ni synergistic catalysis promotes the formation of intermediates (C8H7NO* and C8H7NOH*) and accelerates the rate-determining step (hydrogenation of C8H7NOH*).

Regulating the Surface Electronic Structure of RuNi Alloys for Boosting Alkaline Hydrogen Oxidation Electrocatalysis

“…In Figure c, as well as Figure S13 in the Supporting Information, the XPS spectrum of Ru 3p for O-RuNi@C-400 shows that two peaks located at 462.4 and 484.6 eV belong to Ru 0 3p 3/2 and 3p 1/2 , respectively. The peaks at 466.0 and 487.0 eV correspond to Ru x + 3p 3/2 and Ru x + 3p 1/2 , respectively. − Compared with O-RuNi@C-350, because of the electron transfer from Ni to Ru, the 3p 3/2 peaks of Ru 0 and Ru x+ in O-RuNi@C-400 negatively shifted by ∼0.81 and 0.41 eV, respectively. As shown in O 1s spectrum of O-RuNi@C-400 (Figure d), the peaks at ∼533.6, 531.9, and 530.2 eV correspond to C–O–C, CO, and Ni–O–C, respectively. , As shown in O 1s spectrum of Ni@C-400, we can see the Ni–O–C peak, but compared to O-RuNi@C-400, the Ni–O–C peak is relatively weak.…”

Progress and Perspectives of Single‐Atom Catalysts for Gas Sensing

“…By analyzing the wavelength position of the absorption band and the intensity of the absorption band, the functional groups of SACs structure are obtained. In the in situ FT‐IR spectra of 2 wt% RuNi sample (Figure 4i), except for the appearance of a new band attributed to δ (NH) at 1628 cm −1 , [ 78 ] the band of ν (CC) decreases and fades away preferentially compared with the nitro group (1514 and 1348 cm −1 ). This indicates that both CC and NO 2 are effectively activated on account of the existence of RuRu and RuNi interface sites, respectively, corresponding to the formation of 4‐NE and 4‐AE over 2 wt% RuNi catalyst.…”

“…Scale bar in (a,b) is 300 and 1 nm, respectively. Reproduced with permission [78]. Copyright 2022, Nature Publishing Group.…”

Tracking the Formation of Atomically Dispersed Co-NC Catalyst via Operando XAFS

“…Uniformly anchoring atomically dispersed metals that act as active sites with full utilization, single-atom catalysts have attracted wide attention in the field of catalysis, biomedicine, materials, and so on. − Their identical local configurations not only facilitate the improvement of catalytic activity but also enable the modulation of reaction selectivity. Furthermore, an ideal SACs platform can establish structure–activity relationships to explore catalytic mechanisms benefiting from its well-defined local structure. − Since the official launch of SACs in 2011, great progress has been made in various catalytic systems within the application of SACs. − Among various types of metal SACs, metal and nitrogen-doped carbon (M-NC) have shown unique catalytic performance due to the formation of strong covalent bonding between central metal and adjacent nitrogen atoms (M–N). Compared with other types of SACs, M–N moieties are much more stable in thermodynamic and chemical structures, enabling reaction stability under severe conditions. − With the in-depth research on M-NC catalysts, regulating local atomic and electronic structures is crucial for the rational design of high-performance and long-stability catalysts.…”