The efficient conversion of carbon dioxide into high-value chemicals presents a promising strategy for achieving carbon neutrality. Defects play a critical role in numerous catalytic reactions. However, an excessive number of defects can lead to electron trapping, deactivating the catalyst surface. Optimizing the defect concentration is crucial for significantly enhancing catalytic performance. In this work, two types of flower-like BN-based photocatalysts composed of nanofibers were synthesized by in situ self-assembly and high-temperature calcination. The BN-based photocatalyst with fewer defects (V