A sustainable method toward melamine-based conjugated polymer semiconductors for efficient photocatalytic hydrogen production under visible light

Abstract

The search for conjugated polymer photocatalysts for H₂ production under visible light remains a key challenge. Reported herein is a conjugated polymer (i.e., melamine-terephthalaldehyde polymer (PMTPA)) derived from melamine and terephthalaldehyde precursors without an external solvent through a Schiff-base reaction. By adjusting the polymerization temperature, PMTPA with different sample colors and band gaps was obtained, which was further applied as a photocatalyst to investigate its activity in H₂ evolution. A photocatalytic H₂ evolution efficiency up to 58.1 μmol h⁻¹ was observed over PMTPA polymerized at 250 °C under visible light (λ > 420 nm), which was about two times as high as that of C₃N₄. The Schiff-base reaction without external solvent conditions provides a facile strategy for the synthesis of conjugated polymeric semiconductors with better molecular engineering for advanced applications in the fields of catalysis, energy, and environmental remediation.