Boron-driven oxygen-vacancy enrichment and VOX dispersion in SAPO-34 for robust CO2-ODHP

We report a boron-modified vanadia@SAPO-34 catalyst (V@SP-B) that integrates Lewis-acidic B 3 + sites with redox-active VO X species to enhance CO 2 -assisted oxidative dehydrogenation of propane (CO 2 -ODHP). The catalyst, synthesized via H 3 BO 3 etching and VO(acac) 2 impregnation, forms a hierarchical micro–mesoporous nanoreactor. XRD confirms CHA framework retention with smaller crystallites (31 vs 37 nm), while FT-IR and Raman reveal new B–O/B–O–B bonds, intensified V O vibrations, and vacancy markers indicating increased defect density. HR-XPS shows framework reorganization with higher B 3+ incorporation (66 %), elevated V 4+ /V 5+ ratio (1.3), and a significantly higher oxygen-vacancy ratio (OV/OL = 2.4). Textural analysis demonstrates enhanced surface area (515 m 2 g −1 ) and pore volume (0.46 cm 3 g −1 ). Redox and acid–base studies confirm easier reducibility, stronger hydrogen spillover, enhanced dispersion of active sites (11.4 %), increased acidity (828 µmol g −1 ), and improved CO 2 binding (155 µmol g −1 ). MD simulations support these findings, revealing stronger CO 2 adsorption and lower vacancy formation and reaction barriers. Catalytically, at 550 °C and C 3 H 8 /CO 2 = 2, V@SP-B achieves 18.1 % conversion, 13.7 % yield, and ∼77 % selectivity, maintaining stability over 36 h. The study establishes a direct structure–property–performance relationship driven by boron-induced acid–redox synergy, oxygen-vacancy enrichment, and hierarchical porosity for selective, durable CO 2 -ODHP. • B 3+ incorporation into V 2 O 5 @SAPO-34 forms a hierarchical nanoreactor with higher surface area, porosity, and VO X dispersion. • XRD, FT-IR, Raman, and HR-XPS confirm lattice contraction, B-O linkages, enriched oxygen vacancies, and improved V 4+ /V 5+ balance. • H 2 /CO 2 /NH 3 -TPDs and TPR show enhanced reducibility, stronger spillover, higher CO 2 uptake, and optimized acidity-basicity. • MD simulations reveal longer spillover, stronger CO 2 adsorption, and lower barriers for ODHP and coke removal. • V@SP-B delivers superior CO 2 -ODHP activity (X P = 18.1 %, Y P= = 13.7 %, S P= ≈ 77 % at 550 °C) and excellent stability (3.6 % loss over 36 h).