Flower-like Al2O3 with enriched Brønsted acid sites and oxygen vacancies for synergistic conversion of CH3SH and CO2.

The synergistic conversion of methanethiol (CH3SH), one typical sulfur-containing volatile organic compounds (S-VOCs), and carbon dioxide (CO2) was pivotal for advancing coordinated pollution control and carbon mitigation. However, developing non-metal doped Al2O3 based catalysts that simultaneously enable efficient C-S bond cleavage and CO2 activation remains challenging. Herein, a three-dimensional flower-like γ-Al2O3 catalyst (Al2O3-F) enriched with Brønsted acid sites and oxygen vacancies (Ov) was synthesized via a urea-assisted hydrothermal method. Comprehensive characterizations including 27Al NMR, Pyridine-IR, and EPR, demonstrated that the unique morphology induces reconstruction of the local aluminum coordination environment, promoting the formation of penta-coordinated Al3+ species. This intrinsic structural modulation leads to a high density of thermally stable Brønsted acid sites together with an increased concentration of Ov and enhanced lattice oxygen mobility. As a result, Al2O3-F exhibits superior catalytic activity, lower apparent activation energy, and improved stability in the synergistic conversion of CH3SH and CO2 compared with commercial Al2O3. Crucially, in situ DRIFTS analysis indicate the CO2 hydrogenation-like pathway on Al2O3-F is shifted from the formate (HCOO*) route to the carboxyl (COOH*) route, which is fundamental to the outstanding CO2 hydrogenation capability. This work develops a non-metal doped and efficient alumina-based catalyst and offers new insights into the rational design of multifunctional catalysts for simultaneously eliminating atmospheric pollutants and carbon dioxide.