Dispersed Bi₂S₃ site in a porphyrin-based metal-organic framework for photocatalytic nitrogen fixation

The development of suitable alternatives to the energy-intensive and seriously polluting Haber-Bosch process for ammonia production is crucial. Photocatalytic nitrogen fixation has attracted extensive research attention as a pollution-free, low-cost, and sustainable ammonia production process. However, most reported photocatalysts so far have relatively low conversion rates for N2 reduction. Herein, we employed a strategy based on bismuth precoordination and in-situ sulfurization strategy to grow highly dispersed bismuth sulfide (Bi2S3) on a porous coordination network (PCN) metal-organic framework. The as-fabricated photocatalyst (Bi2S3@PCN-2) with high-density heterojunctions was used for the photocatalytic nitrogen fixation for ammonia production and degradation of bisphenol A, achieving an ammonia production rate of 3880 mu g h-1 g-1 and a 96.4% degradation efficiency for bisphenol A within 30 min in the absence of a sacrificial agent. The abundant porphyrin rings and highly dispersed Bi2S3 broadened the visible-light absorption range of the photocatalyst, leading to numerous photogenerated charge carriers. Additionally, the high-density heterojunctions facilitated the separation of photogenerated electron-hole pairs, resulting in excellent photocatalytic performance. This work provides a new approach for the design and preparation of bifunctional photocatalysts.