Influence of Preparation Methods on the Catalytic Activity of Pd–Cu/Mn₂O₃ Catalyst in the Hydrogenation of 1,3-Butadiene

Abstract

Mn2O3-supported Pd–Cu catalysts synthesized by two biogenic methods, sol-immobilization (SI) and adsorption–reduction, are compared to catalysts prepared via three conventional methods, impregnation (IP), deposition–precipitation with urea (DPU), and deposition of colloids stabilized with poly­(vinylpyrrolidone) (DCPVP). The as-synthesized supported alloy catalysts of sizes between 2 and 8 nm were employed in the gas-phase selective hydrogenation of 1,3-butadiene. Their alloy nature was proved from characterizations including diffuse reflectance infrared Fourier transform spectroscopy and CO adsorption tests, temperature-programmed reduction, X-ray photoelectron spectroscopy, and X-ray diffraction. It was observed that the synthesis method greatly affects the final surface constituent of catalyst Pd/Cu ratio and partial particle reconstruction occurs under CO exposure. The optimum catalyst constituent of Pd–Cu0.06–Mn2O3 was selected since it provided excellent conversion with poor selectivity to unwanted butane. Selectivity of all of the catalysts directly correlated with increasing Cu content and Pd-to-butadiene conversion. The bioreduction-supported catalysts using SI with a Pd/Cu atomic ratio of 0.9:1.4 showed excellent balances between butadiene conversion of 99.1% and selectivity to total butene above 92%, which we attribute to repulsion to H and its neighboring adsorbed inherent C and N atoms with adjacent Pd atoms and alloy synergy. The IPC catalyst showed the worst performance but was highly selective to butenes. And the DCPVP and DPU catalysts with 100% conversion produced worse 1-butene selectivity.

Bimetallic Au–Pd alloy nanoparticles supported on MIL-101(Cr) as highly efficient catalysts for selective hydrogenation of 1,3-butadiene

“…1,2 In recent years, various catalysts, such as nanoparticle supported catalysts and single site catalysts, have been designed and used in diverse chemical reactions. [3][4][5][6][7][8][9][10][11][12][13][14][15] Palladium and gold supported nanoparticle catalysts have been intensively investigated and extensively used in the selective BD hydrogenation because of their superior catalytic activity and selectivity. [14][15][16][17] Previous studies on supported Pd-based nanoparticle catalysts have revealed that they have superior catalytic activity in the selective BD hydrogenation reaction.…”

“…[14][15][16][17] Previous studies on supported Pd-based nanoparticle catalysts have revealed that they have superior catalytic activity in the selective BD hydrogenation reaction. [13][14][15] However, the supported Pd-based catalysts showed a strong affinity to the byproduct butane due to double bond and geometric isomerization, thereby lowering the purity of butenes. [13][14][15] In particular, supported Au-based catalysts were highly selective for BD hydrogenation without overhydrogenation to butane.…”

“…[13][14][15] However, the supported Pd-based catalysts showed a strong affinity to the byproduct butane due to double bond and geometric isomerization, thereby lowering the purity of butenes. [13][14][15] In particular, supported Au-based catalysts were highly selective for BD hydrogenation without overhydrogenation to butane. 16,17 Recently, bimetallic nanoparticle catalysts have attracted much attention in heterogeneous catalysis.…”

“…16,17 Recently, bimetallic nanoparticle catalysts have attracted much attention in heterogeneous catalysis. 13,[18][19][20][21][22] Bimetallic catalysts generally show better catalytic performance than the corresponding monometallic catalysts because catalytic activity could be enhanced by synergistic effects between different components. 23 Hou et al reported that the bimetallic PdNi/g-Al 2 O 3 catalyst shows higher BD hydrogenation activity and 1butene selectivity than Pd/g-Al 2 O 3 and Ni/g-Al 2 O 3 catalysts.…”

“…24 Aguilar-Tapia et al found that the Au-Ni bimetallic nanoparticle catalyst supported on TiO 2 with Au : Ni mole ratio of 1 : 0.08 displays an excellent balance between the activity and butene selectivity for the selective hydrogenation of BD. 25 Pd-Cu 0.06 /Mn 2 O 3 -SI shows a good balance between butene selectivity (92%) and BD conversion (99.1%) at 20 C. 13 Pattamakomsan et al prepared Pd-Sn/MA and Pd/MA (MA ¼ mixed phase alumina) catalysts through impregnation. 26 For the bimetallic Pd-Sn/MA catalyst, the butene selectivity reached to 100% at 80% BD conversion, and butane formation was suppressed.…”