Efficient Solar Driven Upgrading of N2 to Urea Through Photoredox Reactions on Pt Cluster/TiO2

Abstract

AbstractSynthetic nitrogen fertilizers, such as urea, are instrumental in augmenting agricultural output and addressing the demands of a growing population. Nevertheless, conventional urea production heavily relies on energy‐intensive processes. In this study, an environmentally friendly photocatalytic method is proposed for directly and selectively synthesizing urea from nitrogen (N2) and methanol (CH3OH using a Pt cluster‐decorated TiO2 catalyst (Pt cluster/TiO2). Remarkably, the Pt cluster/TiO2 exhibits outstanding urea synthesis performance with a rate of 105.68 µmol g−1 h−1 and N‐selectivity of 97.29 ± 0.79%, representing the highest level of photocatalytic urea synthesis from N2. Further analysis with density functional theory (DFT) calculation reveals that the “σ–π*” donor–acceptor interaction occurred between Pt clusters and N2, efficiently reducing the N2 hydrogenation barrier. EPR experiments demonstrate that photogenerated electrons (e−) and hole (h+) are synchronously consumed through N2 reduction and CH3OH oxidation, thereby accelerating urea synthesis. The crucial step of C─N coupling is initiated by the reaction between *NH─NH and *CHO intermediate, facilitated by the low energy barrier on Pt cluster/TiO2. This work suggests an mild route of urea production and provides profound insights into the underlying chemistry of the C─N coupling reaction, which can guide the sustainable synthesis of essential indispensable chemicals.