ZIF‐Induced d‐Band Modification in a Bimetallic Nanocatalyst: Achieving Over 44 % Efficiency in the Ambient Nitrogen Reduction Reaction

Abstract

The electrochemical nitrogen reduction reaction (NRR) offers a sustainable solution towards ammonia production but suffers poor reaction performance owing to preferential catalyst–H formation and the consequential hydrogen evolution reaction (HER). Now, the Pt/Au electrocatalyst d‐band structure is electronically modified using zeolitic imidazole framework (ZIF) to achieve a Faradaic efficiency (FE) of >44 % with high ammonia yield rate of >161 μg mgcat−1 h−1 under ambient conditions. The strategy lowers electrocatalyst d‐band position to weaken H adsorption and concurrently creates electron‐deficient sites to kinetically drive NRR by promoting catalyst–N2 interaction. The ZIF coating on the electrocatalyst doubles as a hydrophobic layer to suppress HER, further improving FE by >44‐fold compared to without ZIF (ca. 1 %). The Pt/Au‐NZIF interaction is key to enable strong N2 adsorption over H atom.

Identification of M‐NH2‐NH2 Intermediate and Rate Determining Step for Nitrogen Reduction with Bioinspired Sulfur‐Bonded FeW Catalyst

“…Combined with the corresponding O 1s spectrum (Figure S7b), it can be concluded that S−O/S=O bonds exist on the surface of the vulcanized sample, [42] which is consistent with the corresponding FT‐IR spectrum (Figure S5). Because of the presence of sulfur‐oxygen bonds, which are strong electron‐withdrawing groups, the binding energies of Fe and W in FeWS x @FeWO 4 ‐2 positively shifted; this is beneficial for promoting the interactions between N 2 and the catalyst and enhancing the NRR [50] . However, for the excessive vulcanized sample (FeWS x @FeWO 4 ‐4), owing to the reducibility of sulfur, the binding energies of metallic state Fe 0 (721.1 eV and 708.0 eV) and W 4+ (34.7 eV and 32.7 eV) were observed in FeWS x @FeWO 4 ‐4 NPs (Figure S7c and S7d) [42, 51] …”

Nanomaterials for the electrochemical nitrogen reduction reaction under ambient conditions

“…7a). 36 According to the XPS spectra, after encapsulating the ZIF, the binding energy of Pt 4f shifts left and that of N 1s shifts right, clearly highlighting the electron density transfer from Pt to the ZIF framework by the Pt-N ZIF interaction (Fig. 7b).…”

Nitrogenase inspired artificial photosynthetic nitrogen fixation

“…This has been achieved by preparing a porous poly(tetrafluoroethylene) (PTFE) framework as the scaffold for catalyst loading, which enriched N 2 concentration and regulated proton accessibility to favor N 2 transfer over H 2 evolution. 100 Also, coating or confining catalysts with metal organic frameworks (MOFs) [101][102][103] introduced hydrophobic cavities to block water attack but favored N 2 permittivity and adsorption. The decoupled transfer of N 2 and H 2 O molecules improved N 2 transfer and reduction kinetics, as shown in Figure 7B.…”