Designing noble metal single-atom-loaded two-dimension photocatalyst for N2 and CO2 reduction via anion vacancy engineering

Abstract

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.