Template removal from AFI aluminophosphate molecular sieve by Pd/SiO2 catalytic hydrocracking at mild temperature

• Pd/SiO2 catalytic hydrocracking was proved as an efficient method of template removal.
• A mild temperature of 613 K was adopted by the catalytic hydrocracking method.
• The catalytic hydro-cracking method can reserve the local symmetric structure of MnMgAlPO-5.

Pd/SiO2 catalytic hydro-cracking is applied to remove triethylamine template in an AFI type MnMgAlPO-5 molecular sieve. The triethylamine template reacts with spillover hydrogen inletting from the Pd/SiO2 catalyst, and is hydro-cracked to small molecules at a mild temperature (613 K). This behavior is distinguish to the conventional template removal method of calcination above 823 K, and consistently proved by H2-TPR/MS, TG/MS, and N2-isotherms results. The catalytic hydro-cracking method does not damage the crystal structure of MnMgAlPO-5, indicated by XRD characterization. Its novelty is suggested as reserving the local symmetric structure of MnMgAlPO-5 (i.e., keeping framework Mn and Mg), consistently verified by EPR, UV–vis, and Raman spectra. This provides an alternative option for the template removal from molecular sieves.

Energy barrier for hydrocracking of TEA template in MnMgAlPO-5 is easily lowered with Pd/SiO2 catalyst inletting spillover hydrogen.Figure optionsDownload as PowerPoint slide