Solar nitrogen (N2) fixation is the most attractive way for the sustainable production of ammonia (NH3), but the development of a highly active, long-term stable and low-cost catalyst remains a great challenge. Current research efforts for N2 reduction mainly focus on the metal-based catalysts using the electrochemical approach, while metal-free or solar-driven catalysts have been rarely explored. Herein, on the basis of a concept of electron "acceptance-donation", a metal-free photocatalyst, namely, boron (B) atom, decorated on the optically active graphitic-carbon nitride (B/g-C3N4), for the reduction of N2 is proposed by using extensive first-principles calculations. Our results reveal that gas phase N2 can be efficiently reduced into NH3 on B/g-C3N4 through the enzymatic mechanism with a record low onset potential (0.20 V). Moreover, the B-decorated g-C3N4 can significantly enhance the visible light absorption, rendering them ideal for solar-driven reduction of N2. Importantly, the as-designed catalyst is further demonstrated to hold great promise for synthesis due to its extremely high stability. Our work is the first report of metal-free single atom photocatalyst for N2 reduction, offering cost-effective opportunities for advancing sustainable NH3 production.

中文翻译：

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用于可见光驱动的 N2 固定的无金属单原子催化剂

太阳能固氮（N2）是可持续生产氨（NH3）最有吸引力的方式，但开发高活性、长期稳定且低成本的催化剂仍然是一个巨大的挑战。目前 N2 还原的研究工作主要集中在使用电化学方法的金属基催化剂上，而很少探索无金属或太阳能驱动的催化剂。在此，基于电子“接受-给体”的概念，一种无金属的光催化剂，即硼（B）原子，装饰在光学活性的石墨-氮化碳（B/g-C3N4）上，用于还原N2 是通过使用广泛的第一性原理计算提出的。我们的结果表明，气相 N2 可以通过具有创纪录低起始电位 (0.20 V) 的酶促机制在 B/g-C3N4 上有效还原为 NH3。而且，B 修饰的 g-C3N4 可以显着增强可见光吸收，使其成为太阳能驱动的 N2 还原的理想选择。重要的是，设计的催化剂由于其极高的稳定性而被进一步证明在合成方面具有广阔的前景。我们的工作是第一份关于用于 N2 还原的无金属单原子光催化剂的报告，为推进可持续的 NH3 生产提供了具有成本效益的机会。