Catalytic active centers beyond transition metals: atomically dispersed alkaline-earth metals for the electroreduction of nitrate to ammonia

Abstract

Alkaline-earth (AE) metals have been rarely reported to be the active center in heterogenous catalysis. However, nature shows that Mg cofactors in enzymes exhibit super activity for biochemical reactions. Herein,...

Rare-earth La-doped VS2−xfor electrochemical nitrate reduction to ammonia

“…† It is known that the electrocatalytic NO 3 RR process for NH 3 formation comprises the initial deoxidation steps of *NO 3 → *NO 2 → *NO and the following hydrogenation steps of *NOH → *N → *NH → *NH 2 → *NH 3 . [64][65][66] As shown in Fig. 4e, in comparison with VS 2 and VS 2−x , La-VS 2−x shows the lowest energy barrier of −0.63 eV for its rate-determining step (RDS) of *NO → *NOH, suggesting its favorable energetics to boost the NO 3 RR process.…”

p-Block Antimony Single-Atom Catalysts for Nitric Oxide Electroreduction to Ammonia

“…As HER serves as the main competitive reaction of NORR, the HER activity of Sb 1 /a-MoO 3 is further evaluated. − In alkaline or neutral electrolytes, the HER performance of a catalyst is determined by the binding free energies of H 2 O ( G *H 2 O , water activation/dissociation), and H ( G *H , hydrogen generation) . As displayed in Figure d, the Sb 1 site possesses positive G *H 2 O (0.04 eV) and G *H (0.65 eV) but a negative G *NO (−0.38 eV), indicating that the Sb 1 site can favorably absorb NO while repelling H 2 O/H during the NORR process, and thus the competing HER is effectively inhibited on Sb 1 /a-MoO 3 .…”

Self-Tandem Electrocatalytic NO Reduction to NH3 on a W Single-Atom Catalyst

“…Such strong W 1 –O 5 electronic interactions allow W to be atomically dispersed and firmly stabilized in MoO 3– x , resulting in a high thermodynamic stability of W 1 /MoO 3– x (Figure S10). Furthermore, in comparison with the MoO 3 semiconductor, both MoO 3– x and W 1 /MoO 3– x exhibit the occupied electron states across the Fermi level (Figure S11) and reduced work function (Figure S12), thus rendering W 1 /MoO 3– x with enhanced conductivity to accelerate the electron transfer and catalytic kinetics. − …”