Efficient Photocatalytic Nitrogen Fixation: Enhanced Polarization, Activation, and Cleavage by Asymmetrical Electron Donation to NN Bond

Abstract

Photocatalytic nitrogen (N2) fixation suffers from low efficiency due to the difficult activation of the strongly nonpolar NN bond. In this study, a Ru–Co bimetal center is constructed at the interface of Ru/CoSx with S‐vacancy on graphitic carbon nitride nanosheets (Ru‐Vs‐CoS/CN). Upon adsorption, the two N atoms in N2 are bridged to the Ru–Co center, and the asymmetrical electron donation from Ru and Co atoms to N2 adsorbate highly polarized NN bond to double bond order. The plasmonic electric‐field‐enhancement effect enables the Ru/CoSx interface to boost the generation of energetic electrons. The Schottky barrier between Ru and CoSx endows the interface with electron transfer from CoSx to Ru. The Ru‐end bound N at the Ru–Co center is preferentially hydrogenated. As a result, the Ru‐Vs‐CoS/CN photocatalyst shows an NH3 production rate of up to 0.438 mmol g−1 h−1, reaching a high apparent quantum efficiency of 1.28% at 400 nm and solar‐to‐ammonia efficiency of 0.042% in pure water under AM1.5G light irradiation.

Recent advances in photocatalytic nitrogen fixation: from active sites to ammonia quantification methods

“…15 (a) 1 H nuclear magnetic resonance (NMR) spectra were calibrated using dimethyl sulphoxide (DMSO) as an internal standard; (b) the chemical shifts in the spectra were obtained for the 10 vol% methanol solution with 15 N 2 , 14 N 2 , or Ar as the feeding gas, respectively; the chemical shifts in the spectra were obtained for the vol% methanol solution with 15 N 2 (c) and 14 N 2 (d) as the feeding gas. 20 Copyright 2019, Wiley.…”

Polymeric Carbon Nitride‐Derived Photocatalysts for Water Splitting and Nitrogen Fixation

“…[23] Since then, progressively more number of researchers have begun to pay significant attention to the catalytic properties of PCN and applied them immediately to various catalytic reactions. For example, photocatalytic degradation of organic pollutants in water, [39][40][41] photocatalytic N 2 reduction, [10,12,[42][43][44] photocatalytic CO 2 reduction, etc. [45][46][47][48] PCN semiconductor photocatalysts have attracted significant research interest due to their suitable band structure (≈2.7 eV), abundant sources, stable physical and chemical properties, and ease of preparation.…”

“…[ 23 ] Since then, progressively more number of researchers have begun to pay significant attention to the catalytic properties of PCN and applied them immediately to various catalytic reactions. For example, photocatalytic degradation of organic pollutants in water, [ 39–41 ] photocatalytic N 2 reduction, [ 10,12,42–44 ] photocatalytic CO 2 reduction, etc. [ 45–48 ]…”

Inside‐and‐Out Semiconductor Engineering for CO2 Photoreduction: From Recent Advances to New Trends

“…Meanwhile, polarity enhancement and creation of spatially separated active sites as new strategies for enhancing charge separation and optimizing reactive catalytic sites attracts intense attentions. [ 178–180 ]…”

“…Furthermore, the surface grafted halide ions activated the surrounding hydroxyls to boost the adsorption of CO 2 molecules and protons for facilitating the CO 2 conversion. [ 178 ] Without any sacrificial agents or cocatalysts, Br − ‐modified BON showed the highest CO production rate (8.12 μmol g −1 h −1 ) among BON‐X (X = Cl, Br, and I) samples, which was ≈73 times as high as pristine BON (Figure 20e,f).…”