Improved Charge Separation in Poly(heptazine imide) via Schottky Junction for Efficient Photocatalytic CO₂ Reduction

Poly(heptazine imide) (PHI) exhibits impressive photocatalytic performance in CO 2 reduction. However, limited active sites and fast carrier recombination rate are main bottlenecks limiting the application of PHI materials in CO 2 reduction. In this study, a novel MoB/PHI Schottky junction photocatalyst was designed for photocatalytic CO 2 reduction. The optimized 3% MoB/PHI achieves an outstanding CO yield rates of 36.2 µmol g −1 h −1 , surpassing that of PHI (11.2 µmol g −1 h −1 ) by approximately 3.23‐fold. The Schottky junction reduces the interfacial charge transfer resistance and greatly facilitates carrier separation and transfer. Meanwhile, the synergistic interaction between PHI and MoB enriches the electrons on the MoB surface and provides more active sites for CO 2 reduction. This work offers a promising way for constructing photocatalytic systems based on noble metal‐free cocatalysts to enhance photogenerated carrier migration and transport and photocatalytic performance.