Molten salt derived crystalline graphitic carbon nitride to enable selective photo-oxidation of benzyl alcohol

Graphitic carbon nitride with low cost was a fascinating metal-free photocatalyst for alcohol oxidation. However, pristine graphitic carbon nitride typically revealed fast charge recombination owing to incomplete polymerization. Therefore, increasing the degree of polymerization can be one of the effective ways to enhance its photocatalytic activity. Crystalline graphitic carbon nitride was prepared with the aim of modifying charge separation efficiency and increasing crystallinity for advancing catalytic performance by salt melting method. PTI owned a more positive valence band value (2.48 eV) than that of bulk g-C3N4, promising to enhance thermodynamic driving force toward photocatalytic oxidation reactions. In addition, PTI revealed effective adsorption ability for substrates by density functional theory (DFT) calculations. The optimal benzyl alcohol conversion efficiency was 59.3% with selectivity of > 99%. Meanwhile, the recycling experimental results demonstrated that PTI phtocatalyst owed an outstanding reusability and durability. The radical scavenging experiments and EPR analysis demonstrated that both center dot O-2(-) and holes were the main reactive species in photocatalytic alcohol oxidation. This work might offer an avenue to conveniently prepare and bring a new opportunity to exploit photocatalysts with excellent photocatalytic alcohol oxidation performance.

Automated summary

Graphitic carbon nitride is a low-cost metal-free photocatalyst for alcohol oxidation, with increasing polymerization and crystallinity being effective ways to enhance its catalytic activity. The prepared crystalline graphitic carbon nitride showed improved charge separation efficiency and catalytic performance, promising potential for photocatalytic oxidation reactions.