Building highly active and stable noble metal single atom (MSA) catalyst onto photocatalyst materials for nitrogen reduction reaction (NRR) and CO₂ reduction reaction (CRR) is a key to future renewable energy conversion and storage technologies. Here we present a design strategy to optimize the stability and electronic property of noble metal single atoms (MSAs, M = Rh, Pd, Ag, Ir, Pt, Au) catalyst supported on g-C₃N₄ and 2H-MoS₂ photocatalysts towards NRR and CRR. Our results indicate that the MSAs tend to be trapped at the anion-vacancy sites of photocatalyst rather than the pristine photocatalyst surface. This anion vacancy can promise the MSAs with an optimized electron-captured ability in the photoexcitation process, thus decreasing the energy barriers of NRR and CRR on MSAs. Especially, it is revealed that the N-vacancy-stabilized IrSA on g-C₃N₄ and the S-vacancy-stabilized RhSA on 2H-MoS₂ own the lowest energy barrier in NRR. However, for CRR, the HCOOH is the main product on MSAs supported by g-C₃N₄ and 2H-MoS₂. The N-vacancy-stabilized PdSA on g-C₃N₄ and the S-vacancy-stabilized AuSA on 2H-MoS₂ show the lowest energy barrier for HCOOH production in CRR. This finding offers an approach to design specific active MSA centres on photocatalysts by the anion vacancy engineering.

_{在用于氮还原反应（NRR）和CO 2}还原反应（CRR）的光催化材料上构建高活性和稳定的贵金属单原子（MSA）催化剂是未来可再生能源转换和存储技术的关键。在这里，我们提出了一种优化g -C ₃ N ₄和 2H-MoS ₂负载的贵金属单原子（MSAs，M = Rh，Pd，Ag，Ir，Pt，Au）催化剂的稳定性和电子特性的设计策略NRR 和 CRR 的光催化剂。我们的结果表明，MSA 倾向于被困在光催化剂的阴离子空位位置，而不是原始的光催化剂表面。这种阴离子空位可以保证 MSA 在光激发过程中具有优化的电子捕获能力，从而降低 MSA 上 NRR 和 CRR 的能垒。特别地，揭示了g -C ₃ N ₄上的N空位稳定的IrSA和2H-MoS ₂上的S空位稳定的RhSA在NRR中具有最低的能垒。然而，对于 CRR，HCOOH 是 MSA 上的主要产物，由g -C ₃ N ₄和 2H-MoS ₂支持。N空位稳定的PdSAg -C ₃ N _{4和 2H-MoS 2}上的 S-空位稳定 AuSA显示 CRR 中生成 HCOOH 的最低能垒。这一发现提供了一种通过阴离子空位工程在光催化剂上设计特定活性 MSA 中心的方法。