Visible-light-driven photocatalytic hydrogen peroxide production in water via furan–pyrrole polymers: Influence of metal incorporation

Photocatalytic hydrogen peroxide (H 2 O 2 ) production offers a sustainable alternative to the conventional anthraquinone process. However, most inorganic semiconductors exhibit poor selectivity and significant decomposition of the generated H 2 O 2 . In this study, we report the synthesis and photocatalytic evaluation of furan–pyrrole polymers (FPP) featuring a donor-acceptor (D-A) structure, along with their metal-containing derivatives (In, Sn, Tl), under visible-light irradiation without the use of sacrificial agents. The materials were synthesized via one-step thermal polymerization of glucose–urea solutions in the presence of the selected metal species. All samples demonstrated high H 2 O 2 production rates exceeding 2.1 µmol h⁻¹, with minimal decomposition (< 4%). The incorporation of indium resulted in a reproducible enhancement (~8%), which is attributed to improved charge separation and a more favourable conduction band alignment. Scavenger experiments combined with band structure analysis suggested a shift from a sequential one-electron to a direct two-electron oxygen reduction pathway, thereby increasing both selectivity and quantum efficiency for H 2 O 2 production. The FPP-In photocatalyst retained 96% of its activity after five consecutive cycles, demonstrating excellent stability. These findings highlight the potential of donor-acceptor organic polymers as tuneable photocatalysts for solar-driven H 2 O 2 synthesis and provide insights for further material optimization.