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The Ti3AlC2 MAX Phase as an Efficient Catalyst

Ti3AlC2, the first MAX phase to be used in heterogeneous catalysis, efficiently catalyzes the oxidative dehydrogenation (ODH) of n-butane to butenes and butadiene, owing to its defective structure and non-stoichiometric oxide layer on the surface. Dehydrogenation or oxidative dehydrogenation (ODH) of alkanes to produce alkenes directly from natural gas/shale gas is gaining importance. Ti3AlC2, a MAX phase that had not been used in catalysis, efficiently catalyzes the ODH of n-butane to butenes and butadiene, which are important intermediates for the synthesis of polymers and other compounds. The catalyst, which combines metallic and ceramic properties, is stable for at least 30 h on stream, even at low O2:butane ratios, without coking. This material has neither lattice oxygens nor noble metals, yet a unique combination of numerous defects and a thin surface Ti1−yAlyO2−y/2 layer rich in oxygen vacancies make it an active catalyst. Given the many compositions available, MAX phases may find applications in several heterogeneously catalyzed reactions. MAX phases, coined in the late 1990s, are a family of ternary carbides and nitrides with layered hexagonal crystal structures. Their name reflects their chemical formula: Mn+1AXn, where M is an early transition metal, A is an element (mostly from Groups 13 and 14), X is carbon and nitrogen, and n=1, 2, or 3. Most of these phases were discovered in powder form in the 1960s, though the synthesis of phase-pure bulk samples was only achieved in 1996. The MAX phases are interesting because they uniquely combine ceramic and metallic properties. Their bonding is a combination of covalent and metallic. The density of states at the Fermi level is substantial and dominated by the d–d orbitals of the M-element.

Similarly, their electrical resistivity is metal-like, dropping linearly with decreasing temperatures. They conduct heat and electricity like metals, yet they are elastically stiff, strong, and brittle, and some are heat-tolerant, like ceramics. If you are looking for high quality, high purity, and cost-effective Ti3AlC2, or if you require the latest price of Ti3AlC2, please feel free to email contact mis-asia.

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