Ultrahigh Photocatalytic Rate at a Single‐Metal‐Atom‐Oxide

Abstract

Metal oxides, as one of the mostly abundant, low-cost and widely utilized materials, have been extensively investigated and applied in environmental remediation and protection, energy conversion and storage etc [1][2][3][4][5][6][7] . Most of these diverse applications are results of a large diversity of the electronic states of metal oxides. Noticeably, however, numerous metal oxides have obstacles for applications in catalysis because of low density of active sites in these materials. Size reduction of oxide catalyst is a widelyadopted strategy to improve the active site density 8,9 . Here, we demonstrate the fabrication of single tungsten atom oxide (STAO) in which the oxide's size reaches its minimum. However, the catalytic mechanism in this STAO is determined by a quasi-atom physics which is fundamentally distinct from the traditional size effect, and also is in contrast to the standard condensed matter physics. STAO results in a record-high and stable sunlight photocatalytic degradation rate of 0.24 s -1 , which exceeds those of available photocatalysts by approximately two orders of magnitude. The photocatalytic process is enabled by a quasi-atom physical mechanism, in which, an electron in the spinup channel is excited from HOMO to LUMO+1 state (both are largely tungsten atomic d orbitals), which can only occur in STAO with W 5+ . The fabrication of STAO and the discovered unique quasi-atom physics lays a new ground for achieving novel physical and chemical properties using various single metallic atom oxides.

Ultrahigh Photocatalytic CO2 Reduction Efficiency by Single Metallic Atom Oxide on TiO2

“…4.5 wt%) would cause cluster formation, resulting in the decline of PL quenching ( Figure S10). It indicates that STAO at step play a vital role on charge-transfer and charge-trapping, which might be related with unique electronic states of STAO [63]. (Figure 5a and Figure S12).…”

“…Firstly for the uniformly dispersed tungsten, main peaks appearing as shoulders at 34.7 eV (W 4f 7/2) and 36.7 eV (W 4f 5/2) can be identi ed to the W 5+ doublet, while the peaks at 35.8 eV (W 4f 7/2) and 37.8 eV (W 4f 5/2) are due to the W 6+ doublet (Fig. 1d) [63]. It can be noticed that the majority of W on TiO 2 surface exhibit 5+ valence state.…”

“…Thus, a thorough study of atomic-scale con guration on TiO 2 should be undoubtedly applied to enhance the e ciency and selectivity via controlling hydrogenation process. In recent years, the atomic-scale con gurations of single-sites have been developed, i. e. single-atom, single-metal-atom-oxide and single-unit-cell [60][61][62][63]. Following this route for TiO 2 , potential active sites can be designed as a single site anchored on TiO 2 surface [64][65][66][67][68][69][70][71][72][73][74][75], and atomic step site on TiO 2 has been veri ed to enhance electron-transfer and molecular capture capability [76][77][78][79][80] .…”

Enhanced Photocatalytic CO2 Reduction with Defective TiO2 Nanotubes Modified by Single-Atom Binary Metal Components

“…Upon introducing the SAs, a clear quenching of the PL emission peak and 3 times higher photocurrent (3.5 mA/cm -2 ) were observed ( Fig. 4c-d 39,40 , thus the photo-generated electrons would directly transfer from O 2p orbital into Pt 5d orbital, or via Ti 3d orbital into Au 6s orbital 40,41 . The MSI that existed between SAs of Pt/Au and the defects had widen the spectrum of absorptive region, extended the lifetime of the carriers and channelized the electron migration from the defective sites into the SAs metals for which could be an excellent electronic collector and in turn an e cient photocatalysis for CO 2 reduction.…”

Photocatalytic Advanced Oxidation Processes for Water Treatment: Recent Advances and Perspective

“…Such electrons are available for contributing to charge transfer processes, as they may still rertain energy higher than the Schottky barrier energy. [84,85] Xu et al introduced Ag-AgI on to the surfaces of Bi 3 O 4 Cl, and the surface plasma effect of Ag nanoparticles expanded the range of light absorption and response, and significantly improved the degradation rate of methyl orange (MO). Three kinds of electron transfer path in the degradation process of MO was also proposed in this work: AgI CB !Bi 3 O 4 Cl CB , AgI CB !…”