Abstract

Dual single-atom (DSA) catalysts hold great potential, but their synthesis complexity remains a key challenge. Achieving strong interactions between single atoms (SAs) and the support is the main goal in SA catalysis for ensuring robust isolated SA–host interactions. To address this, we introduce a continuous-wave CO₂ laser irradiation strategy that stabilizes SAs in 3 min and demonstrates the feasibility of MBene as a new two-dimensional borides host. Selective acid/oxidant etching expands delaminated MoAl_1−xB MBene sheets, exposing Mo-B rich basal planes, while L-tryptophan functionalized MoAl_1−xB immobilizes Co and Ni DSAs via electron-rich metal–N and metal–O sites under CO₂ laser irradiation (wavelength = 10.6 μm, power = 25 W). The CoNi-DSA/MBene impressively increases electrochemical nitrate reduction reaction (ENRR) activity, achieving an NH₄⁺ production rate of 32.36 mg h⁻¹ cm⁻² at −0.8 V versus RHE. Experimental and theoretical studies confirm that unoccupied Co/Ni d-orbitals accept electrons from NO₃⁻, while occupied d-orbitals donate charge to NO_x p-orbitals, enhancing their electronic coupling with NO₃⁻. This facilitates metal sites to decompose H₂O, generating protons that migrate to NO₃⁻ intermediates, promoting hydrogenation for efficient ENRR. Furthermore, Ar stripping/acid trapping was employed for NH₃ collection to ensure practicality of NH₃ production. Beyond ENRR, CoNi-DSA/MBene is employed as the cathode in a Zn–NO₃⁻ battery, offering advanced energy solutions with NH₃ production. This study underpins the potential of CO₂ laser processing as a new avenue for the rational design of multifunctional SA catalysts in energy technologies.