Fig. 6. Effect of the lead to tin molar ratio on the yields of main products with Pb–Sn-beta reaction conditions: 190 °C, 2 h, air, 225 mg glucose and 200 mg catalyst (0.3 mmol g⁻¹ metal loading). LA: lactic acid, AA: acetic acid, FA: formic acid, and GLY: glycolic acid.