Manipulation of zeolite composition through judicious choice of an organic structure-directing agent (OSDA) is essential to regulate its physicochemical properties. ZSM-48 is a unidimensional zeolite that often crystallizes into siliceous form, and direct synthesis of the aluminous counterpart using low-cost OSDAs is thus far a bottleneck that has obstructed its deployment in large-scale implementation. This work shows the use of a specific OSDA, allyltrimethylammonium chloride, which structurally mimics the iso-alkyl carbenium ion intermediate found in n-heptane skeletal isomerization, is capable of producing aluminous ZSM-48 with more accessible protonic sites. The specificity of this OSDA is ascribed to the good match of its molecular size and shape to the microchannel geometry of the structure and its rigidity endowed by the presence of the CHCH 2 moiety. The obtained material (a Si/Al ratio of ca. 23.0) possesses more medium-to-strong Bronsted acid sites (by a factor of 1.36) and enhanced diffusion property (12 times) with respect to a control sample (Si/Al of ca. 26.7) derived from an expensive, often used OSDA, pentamethonium bromide, as evidenced by NH 3 -IR spectroscopy and gravimetric adsorption uptake measurement using 2-methylhexane as a probe molecule, respectively. The difference in acid site density between the two samples can be ascribed to the influences of OSDA on crystallinity, amount of Al incorporation, and associated Al sitting. A significant increase in isomer yield from 44 to 72% in n-heptane hydroisomerization has been attained using the obtained ZSM-48 as an acid catalyst with respect to the control sample.

The surface oxygen vacancy of metal oxide is a type of important catalytic active site. To investigate the origin and nature of oxygen vacancy, CeO 2 nanorods with exposed {110} facets were treated at different temperatures under H 2 atmosphere. 1 H MAS NMR, 31 P MAS NMR with trimethylphosphine (TMP) as the probe molecule, in situ XPS, and in situ EPR were employed to characterize the surface oxygen vacancy of the reduced samples. The results show that the decrease of the hydroxyl group content and the increase of Ce 3+ concentration occur gradually with the increase of reduction temperature. When the temperature reaches 350 °C, the surface and bulk oxygen vacancies of CeO 2 are generated. The longitudinal relaxation time (T 1 ) and the motion of 31 P nuclei from TMP molecules adsorbed on the CeO 2 surface were found to be significantly reduced with the formation of surface oxygen vacancies. Based on the characterization results, the adsorption models of probe molecules on the surface of the samples are established and the amount of surface oxygen vacancies can be estimated quantitatively.

A house-of-cards architecture of silicoaluminophosphate was fabricated to enhance selectivity for hydroisomerization.