Interfacial Charging–Decharging Strategy for Efficient and Selective Aerobic NO Oxidation on Oxygen Vacancy

Abstract

Intelligent defect engineering to harness surface molecular processes is at the core of selective oxidation catalysis. Here, we demonstrate that the two-electron-trapped oxygen vacancy (VO) of BiOCl, a prototypical F center (VO ̋′′), is a superb site to confine O2 toward efficient and selective NO oxidation to nitrate. Stimulated by solar light, VO ̋′′ accomplishes NO oxidation through a two-electron charging (VO ̋′′ + O2 → VO ̋′′-O2 2–) and subsequent one-electron decharging process (VO ̋′′-O2 2– + NO → VO-NO3 – + e–). The back-donated electron is retrapped by VO to produce a new single-electron-trapped VO (VO′), simultaneously triggering a second round of NO oxidation (VO′-O2 + NO → VO-NO3 –). This unprecedented interfacial charging–decharging scheme alters the peroxide-associated NO oxidation selectivity from NO2 to NO3 – with a high efficiency and thus hold great promise for the treatment of risky NO x species in indoor air.

Dual-function surface hydrogen bonds enable robust O2 activation for deep photocatalytic toluene oxidation

“…4c). 35 The concentration of OVs can then be semi-quantitatively determined by the percentage of Bi (3−x)+ , similar to the determination of OVs by Ti 3+ in oxygen-deficient TiO 2 (Fig. 4c).…”

“…Bi 3+ in BiOCl. 35 After phosphoric acid adsorption, Bi 4f XPS binding energies of P-BiOCl experienced no remarkable change (Fig. 3c).…”

“…Since OVassociated defect states usually lie beneath the conduction band (CB) of BiOCl, the SPV emission at longer wavelength was therefore attributed to the indirect excitation of BiOCl. 35,44 During the indirect excitation process, in situformed OVs acted as the springboard to capture and mediate the transfer of electrons from the VB to CB, thus inhibiting electron-hole recombination (Fig. 4f).…”

“…47,48 The PL decaying curves were collected at the emission peak around 600 nm with atmospheric O 2 , which was the indirect radiative recombination of electrons on the OVs with photoholes on the VB. 35 We denoted such defect PL emission as PL OV . In an O 2 atmosphere, decaying PL OV of BiOCl could be fitted using…”

Unveiling real active site for photocatalytic H2O2 evolution: A combined experimental and DFT-TDDFT study

“…Meanwhile, the two β-LUMO orbitals that were originally degenerate in the isolated O 2 all became occupied orbitals ( Supplementary Fig. 14), indicating that O 2 obtained two electrons, which became endoperoxide on the NDCN surface 38,39 .…”