Highly Selective Acetylene Semihydrogenation Catalyst with an Operation Window Exceeding 150 °C

Abstract

The operating window (OW) is a primary performance criterion for the selective hydrogenation of acetylene in excess ethylene. Currently, most state-of-the-art catalyst systems have an OW of less than 50 °C in front-end processes. Selective acetylene hydrogenation catalysts with an OW wider than 100 °C are rare. Here, we demonstrate a facile stepwise chemical method to synthesize calcite-supported PdBi intermetallic compounds (PdBi/Calcite) that feature isolated and electron-rich Pd atoms as active sites for acetylene hydrogenation. Beneficial from the extremely weak ethylene absorption abilities and the stable structures against the formation of β-PdH x , PdBi/Calcite exhibit >99% selectivity to C 2 H 4 in the whole temperature range tested (50−300 °C) and ∼100% C 2 H 2 conversion from 150 to 300 °C. As a result, an operation window exceeding 150 °C has been achieved.

Engineering Pt-Bi2O3 Interface to Boost Cyclohexanone Selectivity in Oxidative Dehydrogenation of KA-Oil

“…In addition, the relative intensity of band assigned to step sites adsorption also increases (blue line). When the bismuth amount increased to 0.2%, only one broad peak located at 2052 cm −1 is left and the stretching frequency is red-shifted by 12 cm Combination of both theoretical calculations and experimental characterizations revealed both geometric and electronic effects of small amount of Bi2O3 on the Pt structure, which might affect its catalytic performance as suggested by literatures [15,18,36]. The asprepared PtBix/SiO2 (x = 0-0.3) was then applied in the selective oxidative dehydrogenation of KA-oil.…”

“…The XRD pattern of the spent PtBi0.2/SiO2 composite after the long-term test did not appear to have any new diffraction peaks, which verified the stability of the Pt-Bi system and good dispersion of Bi (Figure 4a). Combination of both theoretical calculations and experimental characterizations revealed both geometric and electronic effects of small amount of Bi 2 O 3 on the Pt structure, which might affect its catalytic performance as suggested by literatures [15,18,36]. The as-prepared PtBi x /SiO 2 (x = 0-0.3) was then applied in the selective oxidative dehydrogenation of KA-oil.…”

“…The biggest challenge in the ODH of KA-oil is the competitive adsorption between ketone and alcohol, which results in low alcohol conversion and non-ideal ketone selectivity. To address this problem, it is of great importance to develop advanced catalysts that feature a weak adsorption of cyclohexanone but have a strong adsorption of cyclohexanol The adsorption behavior of heterogeneous catalysts is generally determined by their surface geometric and electronic structures [13][14][15]. For a structure-sensitive reaction, different crystal planes might exhibit different adsorption behaviors towards reactants and products.…”

“…For example, Villa et al reported that the addition of Bi into PdAu/C can significantly improve the selectivity in ODH of benzyl alcohol because Bi blocks partial of active sites and suppress parallel reaction in ODH of benzyl alcohol [18]. In addition to geometric effect, creating metal-metal [15,19], metal-support [20] or metal-organic interfaces [14] to tune the electronic structures of metal nanoparticles is also an important strategy to regulate their adsorption behaviors. Among them, p-electron metal Bi, is frequently used as a modifier to engineer the electronic structure of Pd and Pt as it can donate electrons to these active species and prevent them from being overoxidized [21,22].…”

Design of Pd–Zn Bimetal MOF Nanosheets and MOF-Derived Pd3.9Zn6.1/CNS Catalyst for Selective Hydrogenation of Acetylene under Simulated Front-End Conditions

“…Removing trace amount of acetylene (~1%) from ethylene feed is commercially important because acetylene will poison Ziegler–Natta ethylene-polymerization catalysts [ 27 ]. Selective hydrogenation is the most effective and widespread method in industry for diminishing the acetylene impurity to an acceptable level and re-utilizing it as the raw material for the polyethylene process [ 28 ]. Palladium is the most active metal for selective hydrogenation of acetylene, as a result, palladium-based catalysts are the most widely used in industry for this reaction.…”