High-Efficiency N2 Electroreduction Enabled by Se-Vacancy-Rich WSe2-x in Water-in-Salt Electrolytes

PdFe Single-Atom Alloy Metallene for N2 Electroreduction

Single-atom alloys hold great promise for electrocatalytic nitrogen reduction reaction (NRR), while the comprehensive experimental/theoretical investigations of SAAs for the NRR are still missing. Herein, PdFe₁ single-atom alloy metallene, in which the Fe single atoms are confined on a Pd metallene support, is first developed as an effective and robust NRR electrocatalyst, delivering exceptional NRR performance with an NH₃ yield of 111.9 μg h^-1  mg^-1 , a Faradaic efficiency of 37.8 % at -0.2 V (RHE), as well as a long-term stability for 100 h electrolysis. In-depth mechanistic investigations by theoretical computations and operando X-ray absorption/Raman spectroscopy indentify Pd-coordinated Fe single atoms as active centers to enable efficient N₂ activation via N₂ -to-Fe σ-donation, reduced protonation energy barriers, suppressed hydrogen evolution and excellent thermodynamic stability, thus accounting for the high activity, selectivity and stability of PdFe₁ for the NRR.

A vacancy engineered MnO2-x electrocatalyst promotes nitrate electroreduction to ammonia

The NO₃^- reduction reaction (NO₃RR) has recently emerged as a potential approach for sustainable and efficient NH₃ production, whereas exploring high-performance NO₃RR electrocatalysts is highly desirable yet challenging. Herein, we attempted to construct O-vacancies (OVs) on MnO₂ nanosheets and the resulting OV-rich MnO_2-x showed a high NH₃ yield of 3.34 mg h^-1 cm^-2 (at -1.0 V vs. RHE) and an excellent FE of 92.4% (at -0.9 V vs. RHE), together with the outstanding stability. DFT calculations reveal that OVs on MnO₂ serve as catalytic centers to enhance NO₃^- adsorption and dissociation, reduce the energy barriers of hydrogenation steps and thus promote NO₃^--to-NH₃ conversion.

Boosted nitrate electroreduction to ammonia on Fe-doped SnS2 nanosheet arrays rich in S-vacancies

The electrochemical nitrate reduction reaction (NO₃RR) not only holds great potential for the removal of NO₃^- contaminants from the environment, but also potentially provides a renewable-energy-driven NH₃ synthesis method to replace the Haber-Bosch process. Herein, we report that Fe-doped SnS₂ nanosheets enriched with S-vacancies can be used as an efficient NO₃RR catalyst, showing a high NH₃ yield of 7.2 mg h^-1 cm^-2 (at -0.8 V) and a faradaic efficiency of 85.6% (at -0.7 V). Density functional theory (DFT) calculations revealed that S-vacancies on Fe-SnS₂ serve as the main active sites for the NO₃RR and the Fe-doping can further regulate the electronic structure of S-vacancies to optimize the binding energies of NO₃RR intermediates, resulting in reduced energy barriers and enhanced NO₃RR activity.

Direct eight-electron NO3−-to-NH3 conversion: using a Co-doped TiO2 nanoribbon array as a high-efficiency electrocatalyst

A Co-TiO2 nanoribbon array supported on a Ti plate is a high-efficiency catalyst for electrochemical NO3–-to-NH3 conversion, capable of attaining a large NH3 yield of 1127 μmol h−1 cm−2 and high Faradaic efficiency of 98.2%.