Silica Coating of Metal-Loaded H-ZSM-22 to Form the Core-Shell Nanostructures: Characterization, Textural Properties, and Catalytic Potency in the Esterification of Oleic Acid

Table 1

The synthesized catalysts in different conditions.

Entry	Catalyst	Si/Al		pH	Synthesis temp. (°C)	Calcination temp. (°C)	Synthesis time (h)	Calcination time (h)
		Targeted	Measured^a
1	ZSM-22	50	23	8.1	160	550	48	6
2	H-ZSM-22	40	13.26	7.8	160	550	48	6
3	H-ZSM-22	50	21.7	7	160	550	48	12
4	H-ZSM-22	75	26.11	7.3	160	550	48	12
5	H-ZSM-22	95	29.54	7	160	550	48	12
6	H-ZSM-22	95	29	7.8	160	550	72	12
7	H-ZSM-22	95	28.8	7.7	160	550	96	12
8	Fe-H-ZSM-22	50^b	21.7^c	7.8	160	550	48	6
9	Sr-H-ZSM-22	50^b	21.7^c	7.4	160	550	48	6
10	Zr-H-ZSM-22	50^b	21.7^c	7.7	160	550	48	6
11	Fe-H-ZSM-22@SiO2	50^b	21.7^c	7.8	150	550	60	12
12	Sr-H-ZSM-22@SiO2	50^b	21.7^c	7.7	150	550	60	12
13	Zr-H-ZSM-22@SiO2	50^b	21.7^c	7.3	150	550	60	12

^aSi/Al ratio was measured by EDS analysis. ^bThis value is the initially used ratio for H-ZSM-22 synthesis applied for metal immobilization and core synthesis. ^cThe Si/Al ratio was measured and reported for H-ZSM-22 used for metal immobilization and core synthesis.