Intelligent Optimization of Na−Mn−W/SiO₂ Catalysts for the Oxidative Coupling of Methane

Abstract

Optimizing the performance and understanding the mechanism of metal oxide catalysts in the oxidative coupling of methane (OCM) is one of the most important projects in industrial catalysis. Here, we report an intelligent approach to screen Na−Mn−W/SiO2 catalysts for the OCM reaction via ink‐jet printing and multidimensional group testing. The ink‐jet‐printing‐assisted (IJP‐A) synthetic methodology ensured a fast synthesis of 1536 catalysts that were evaluated in 24 tests via a multidimensional group testing strategy (m‐GT). After two‐round synthesis‐and‐screening processes, several excellent groups with different composition space were screened out. Among the excellent catalysts, the OCM performance of Na−Mn−W/SiO2 catalyst with higher Na, Mn and W content (G3 and G7) was less sensitive to its constituent than that of Na−Mn−W/SiO2 catalyst with lower Na, Mn and W content (G1). These results indicated the sensitivity of performance to its Na, Mn and W content decreased in larger Na, Mn and W spaces, consistent with the complex homogeneous/heterogeneous reaction mechanism and multi‐active sites. A series of Na−Mn−W/SiO2 formulas with good performance also provide a reasonable explanation to its excellent stability for the OCM reaction. In addition, this intelligent optimization in total space offers a pathway to study the multicomponent metal oxide catalyst in the OCM reaction.

CH3•-Generating Capability as a Reactivity Descriptor for Metal Oxides in Oxidative Coupling of Methane

“…Oxidative coupling of methane (OCM) is an economically valuable and promising route to directly convert the abundant feedstock of natural gas into valuable C 2 hydrocarbons (C 2 H 6 and C 2 H 4 ). − Techno-economic analysis suggests that a target C 2 yield of around 30% would make the process comparable to the benchmark ethylene production technologies and applicable on an industrial scale. , However, no catalyst system has achieved this target under conditions optimal for industrial production, despite extensive efforts for 40 years . The main issue is that the thermodynamically stable overoxidation products, CO x , are formed in the presence of oxygen, which places an upper limit on C 2 yield of 25–28%. , Conventionally, most OCM studies are performed using a “synthesize and test” strategy with a focus on maximization of the C 2 yield .…”

3D Printed Materials in Water Treatment Applications

“…The catalysis system has shown 3% and 40% conversion of methane at 700 and 800 °C, respectively. [ 85 ] Whereas, the 3D printed carbon material (N‐doped) with meso/macro pores has shown notable enhancement for the methylene blue adsorption efficiency of 93.2% in 10 min. [ 86 ] Furthermore, mixed chitosan powder and thermoplastic polyurethane composite membrane loaded with palladium were used as a catalyst for the photodegradation of 4‐nitrophenol by sodium borohydride, which showed up to 92% removal efficiency.…”

Oxidative Coupling of Methane for Ethylene Production: Reviewing Kinetic Modelling Approaches, Thermodynamics and Catalysts

“…However, to the best of our knowledge, multimetallic catalyst systems comprising Me-W-Mn-O/SiO 2 , in which Me stands for Na or Ce, and TiO 2 -doped Na-W-Mn-O/SiO 2 , represent some of the few catalytic systems for which thermal stability has been shown to endure for up to 500 and 1000 h [50,134,179,180]. Not surprisingly, these catalysts have been extensively investigated in an attempt to understand the reasons for their outstanding stability and identify active sites [44,181]. However, as noted previously 181 , the identity of active sites associated with these systems remains under debate [182,183], with more recent findings suggesting sodium oxide species as active sites which would remain stable due to 'synergistic' effects between Na 2 WO 4 and Mn 7 SiO 12 phases [182].…”