Visible light-triggered catalytic conversion of D-glucose to sorbitol using magnesium oxide/graphitic carbon nitride nanocomposites

The polymeric graphitic carbon nitride (g-C₃N₄) was modified by attaching magnesium oxide nanoparticles (MgO NPs) to improve charge separation efficiency. The resultant photo-responsive MgO/g-C₃N₄ nanocomposites (NCs) exhibited significantly greater catalytic activity for hydrogen generation compared to both g-C₃N₄ nanosheets and MgO NPs, producing hydrogen at rates that were 2.13 times and 8.12 times faster, respectively. Additionally, the ability of MgO/g-C₃N₄ NCs to catalyze the degradation of methylene blue (MB) dye was evaluated. A novel catalytic hydrogen transfer (CHT) method was developed to convert D-glucose to D-sorbitol using the MgO/g-C₃N₄ photonanocatalyst in a 1:1 mixture of aqueous ethanol and water at room temperature, under visible light irradiation, and atmospheric pressure, without the need for additional molecular hydrogen. After 4 h of irradiation, using 100 ppm of the catalyst and 10% NaHSO₃ as a hydrogen donor (NaHSO₃:catalyst, 1:10, w/w), a highly selective conversion rate of 93% of glucose to sorbitol was achieved. Catalyst recycling studies demonstrated sustained activity after five cycles. This methodology not only outperforms previously studied techniques but also offers a green and efficient approach to sorbitol production under mild conditions.