Multifunctional Catalyst Combination for the Direct Conversion of CO₂ to Propane

Abstract

The production of carbon-rich hydrocarbons via CO 2 valorization is essential for the transition to renewable, non-fossil-fuel-based energy sources. However, most of the recent works in the state of the art are devoted to the formation of olefins and aromatics, ignoring the rest of the hydrocarbon commodities that, like propane, are essential to our economy. Hence, in this work, we have developed a highly active and selective PdZn/ZrO 2 +SAPO-34 multifunctional catalyst for the direct conversion of CO 2 to propane. Our multifunctional system displays a total selectivity to propane higher than 50% (with 20% CO, 6% C 1 , 13% C 2 , 10% C 4 , and 1% C 5 ) and a CO 2 conversion close to 40% at 350 °C, 50 bar, and 1500 mL g –1 h –1 . We attribute these results to the synergy between the intimately mixed PdZn/ZrO 2 and SAPO-34 components that shifts the overall reaction equilibrium, boosting CO 2 conversion and minimizing CO selectivity. Comparison to a PdZn/ZrO 2 +ZSM-5 system showed that propane selectivity is further boosted by the topology of SAPO-34. The presence of Pd in the catalyst drives paraffin production via hydrogenation, with more than 99.9% of the products being saturated hydrocarbons, offering very important advantages for the purification of the products.

Modifying the Hydrogenation Activity of Zeolite Beta for Enhancing the Yield and Selectivity for Fuel‐Range Alkanes from Carbon Dioxide

“…This fraction is used as liquefied petroleum gas (LPG) which has important applications both industrially (heating) and residentially (heating, cooking). [12] Analyzing the heavier paraffin range (C 5 -C 8 ) we once again confirm that 325 °C seems to be the optimal temperature of operation since it has significantly more selectivity to this fraction as compared to 300 °C and better ratio of branched to linear paraffins than 350 °C.…”

“…From the results presented in Figure 2, we see that regardless of the reaction temperature, the light paraffin fraction (C 2 –C 4 ) consists majorly of propane and butanes (both n‐ and iso‐butane). This fraction is used as liquefied petroleum gas (LPG) which has important applications both industrially (heating) and residentially (heating, cooking) [12] …”

Evaluating the Role of Descriptor- and Spectator-Type Reaction Intermediates During the Early Phases of Zeolite Catalysis

“…: CO 2 -derived FTS is associated with the reverse water-gas shift reaction (RWGS: CO 2 + H 2 ⇌ CO + H 2 O)) and (ii) methanol synthesis over a metallic catalyst (CO + 2H 2 → CH 3 OH; CO 2 + 3H 2 → CH 3 OH + H 2 O) in combination with the zeolite-mediated classical MTH process (Figure ). ,,− ,− Similar to MTH/MTO chemistry, the zeolite-based hybrid inorganic–organic supramolecular reactive centers also influence the catalysis during the direct hydrogenation of CO/CO 2 . ,,, Therefore, the impact of the organic reaction intermediate is inevitable in zeolite catalysiseither governing the catalysis (descriptor) or promoting the deactivation (spectator). Both deserve equal attention by carefully evaluating their profiles to have the desired selectivity and catalyst lifetime.…”

Simultaneously Achieving High Conversion and Selectivity in Syngas-to-Propane Reaction via a Dual-Bed Catalyst System

“…Until now, a variety of hydrocarbon fuels (i.e., gasoline and diesel) and chemicals (i.e., light olefins and aromatics) have been synthesized from syngas by using Fischer–Tropsch (F–T) − or oxide–zeolite (OX-ZEO) bifunctional catalysts. − Due to the control of Anderson–Schulz–Flory distribution, it is not easy to obtain a single hydrocarbon product by conventional F–T synthesis. Recently, with the progress of OX-ZEO catalyst design, some single hydrocarbons, such as ethane, ethylene, propane, , and tetra-methylbenzene, have been synthesized with a relatively higher selectivity, but the yield of the target product is still unsatisfactory. In our opinion, there are at least two reasons for the low yield.…”

“…7−11 Due to the control of Anderson− Schulz−Flory distribution, it is not easy to obtain a single hydrocarbon product by conventional F−T synthesis. Recently, with the progress of OX-ZEO catalyst design, some single hydrocarbons, such as ethane, 12 ethylene, 13 propane, 14,15 and tetra-methylbenzene, 16 have been synthesized with a relatively higher selectivity, but the yield of the target product is still unsatisfactory. In our opinion, there are at least two reasons for the low yield.…”