In the study, an HPW–PDMAEMA–SiO2 (phosphotungstic acid (HPW); poly-N,N-dimethylaminoethyl methacrylate (PDMAEAM)) catalyst was successfully synthesized.
Density functional theory calculations were used to investigate the mechanism of acetylene hydrochlorination separately catalyzed by un-doped B12N12 and carbon-doped BN fullerene (B12−nN11+nC (n = 0, 1)).
The mechanisms of acetylene hydrochlorination to vinyl chloride catalyzed by neutral Au3–10 clusters were systematically investigated using density functional theory with the B3LYP/LANL2DZ function.
Ethylene is an important chemical raw material and with the increasing consumption of petroleum resources, the production of ethylene through the calcium carbide acetylene route has important research significance. In this work, a series of bimetallic catalysts with different Cu/Ni molar ratios are prepared by co-impregnation method for the hydrogenation of calcium carbide acetylene to ethylene. The introduction of an appropriate amount of Cu effectively inhibits not only the formation of ethane and green oil, thus increasing the selectivity of ethylene, but also the formation of carbon deposits, which improves the stability of the catalyst. The ethylene selectivity of the Ni–Cu bimetallic catalyst increases from 45% to 63% compared with the Ni monometallic counterpart and the acetylene conversion still can reach 100% at the optimal conditions of 250 °C, 8000 mL·g−1·h−1 and V(H2)/V(C2H2) = 3. X-ray diffraction and transmission electron microscopy confirmed that the metal particles were highly dispersed on the support, High-resolution transmission electron microscopy and H2-Temperature programmed reduction proved that there was an interaction between Ni and Cu, combined with X-ray photoelectron spectroscopy and density functional theory calculations results, Cu transferred electrons to Ni changed the Ni electron cloud density in NiCux catalysts, thus reducing the adsorption of acetylene and ethylene, which is favorable to ethylene selectivity.
Expanded multilayered vermiculite (VMT) was successfully used as catalyst support and Ni/VMT synthesized by microwave irradiation assisted synthesis (MIAS) exhibited excellent performance in our previous work. We also developed a two-dimensional porous SiO2 nanomesh (2D VMT-SiO2) by mixed-acid etching of VMT. Compared with three-dimensional (3D) MCM-41, 2D VMT-SiO2 as a catalyst support provided a superior position for implantation of NiO species and the as-obtained catalyst exhibited excellent performance. In this paper, we successfully synthesized a layered double hydroxide (LDH) using the spent liquor after mixed-acid etching of VMT, which mainly contained Mg2+ and Al3+. The as-calcined layered double oxide (LDO) was used as a catalyst support for CO methanation. Compared with Ni/MgAl-LDO, Ni/VMT-LDO had smaller active component particles; therefore, in this study, it exhibited excellent catalytic performance over the whole temperature range of 250–500 °C. Ni/VMT-LDO achieved the best activity with 87.88% CO conversion, 89.97% CH4 selectivity, and 12.47 × 10−2·s−1 turn over frequency (TOF) at 400 °C under a gas hourly space velocity of 20,000 mL/g/h. This study demonstrated that VMT-LDO as a catalyst support provided an efficient way to develop high-performance catalysts for synthetic natural gas (SNG) from syngas.