Operando Oxygen Vacancies for Enhanced Activity and Stability toward Nitrogen Photofixation

Abstract

Photocatalysts with oxygen vacancies (OVs) have exhibited exciting activity in N2 photofixation due to their superiority in capture and activation of N2. However, the surface OVs are easily oxidized by seizing the oxygen atoms from water or oxygen during the catalytic reaction. Here, it is reported that the grain boundaries (GBs) in nanoporous WO3 induce plenty of operando OVs under light irradiation to significantly boost catalytic activity toward N2 photofixation. Impressively, nanoporous WO3 with abundant GBs (WO3‐600) exhibit an ammonia production rate of 230 µmol gcat.−1 h−1 without any sacrificial agents at room temperature, 17 times higher than that for WO3 nanoparticles without GBs. Moreover, WO3‐600 also manifests remarkable stability by maintaining nearly ≈100% catalytic activity after ten successive reaction rounds. Further mechanistic studies reveal that both OVs and GBs regulate the band structures of WO3 nanocrystals, as well as favor the delivery of photogenerated electrons to adsorbed N2 by enhancing W–O covalency. More importantly, plenty of operando OVs induced by GBs generate during catalytic reaction, directly contributing to the excellent catalytic performance for WO3‐600. This work opens a novel avenue to developing efficient photocatalysts by construction of operando OVs.

Understanding and Optimizing Ultra‐Thin Coordination Polymer Derivatives with High Oxygen Evolution Performance

“…For the XPS spectrum of O 2s in NiFe‐LDH (Figure 3e), three main peaks located at 529.68, 531,39, and 532.98 eV, respectively, are assigned to metal‐oxygen bonds, surface hydroxyl groups, and adsorbed water. [ 53–58 ] However, the binding energies in the O2s XPS spectrum of R‐NiFe‐CPs are shifted slightly to higher values and a new peak located at 531.57 eV appears, which can be assigned to oxygen deficiencies. [ 33a,b,56–60 ] The negative shift for Ni and Fe 2p and the positive shift for O 2s are due to strong electronic interactions with electron transfer from anions to cations.…”

“…[ 53–58 ] However, the binding energies in the O2s XPS spectrum of R‐NiFe‐CPs are shifted slightly to higher values and a new peak located at 531.57 eV appears, which can be assigned to oxygen deficiencies. [ 33a,b,56–60 ] The negative shift for Ni and Fe 2p and the positive shift for O 2s are due to strong electronic interactions with electron transfer from anions to cations. [ 29a,b,32,61 ] Overall, the charge regulation by structural deficiencies and distortions in R‐NiFe‐CPs caused electron redistributions, which enhance the electron transfer properties and further improve the OER performance, as will be discussed in the following sections.…”

Facile Fabrication of Z-Scheme Bi2WO6/WO3 Composites for Efficient Photodegradation of Bisphenol A with Peroxymonosulfate Activation

“…The electrochemical impedance spectra (EIS) and photocurrent responses were conducted to explore the interfacial charge separation efficiency, and the results are depicted in Figure 11. Generally, a lower radius of the Nyquist plot represents a faster interfacial charge transport [45,46].…”

“…The electrochemical impedance spectra (EIS) and photocurrent responses were conducted to explore the interfacial charge separation efficiency, and the results are depicted in Figure 11. Generally, a lower radius of the Nyquist plot represents a faster interfacial charge transport [45,46]. The electrochemical impedance spectra (EIS) and photocurrent responses were conducted to explore the interfacial charge separation efficiency, and the results are depicted in Figure 11.…”

Keggin‐Type Polyoxometalate‐Based ZIF‐67 for Enhanced Photocatalytic Nitrogen Fixation

“…To solve the above problems, the key task is constructing photocatalystst hat are provided with active sites to efficiently adsorbN 2 and electrondonation centers with low energy for transferringi nterfacial charge to activate N 2 . [16,17] Metal-organic frameworks (MOFs)t hat consist of the metal ions acting as the coordination centers and the organic molecules clusters serving as the linker ligands, are ak ind of novel crystal compound materials. MOFs have been recognized as a spotlightw ith outstanding efficiencies in both environmental and energy applications, such as gas and energy storage,c onversion, and catalysis owing to periodic and porous structures, high specific surface area,a nd versatility.…”