Ultra‐stable Molecular Interface SiW₁₂O_x/TiO₂ Catalyst Derived from Keggin‐type Polyoxometalates for Photocatalytic Conversion of Methane to Oxygenates

Abstract

The interface and surface acidity of heterogeneous catalysts are widely applied to manipulate the catalytic performance. However, the interface structure prepared by traditional synthesis processes required multistep procedures, which was still lack of controllability and stability. Here, we show a general synthetic approach to fabricate ultra-stable heterogeneous catalysts with tailored molecular interfacial structure and super acidity in one step. The as-synthesized SiW 12 O x /TiO 2 catalyst was used for photo-catalytic conversion of methane to value-added oxygenates. We propose that the formed molecular interface W 12 À OHÀ Ti coupled with the introduced Brønsted acid sites of POMs, results in enhancing the photocatalytic performance. Namely, the addition of SiW 12 O x can reduce the recombination of electrons and holes for triggering charge separation owing to the photoelectron capturing by proton, improving electron transfer to reactants and thereby promoting catalytic activity. This fabrication method provides a way to build molecular interface photo-catalyst by POMs with super acidity and ultrastable structure.

Steering Photooxidation of Methane to Formic Acid over A Priori Screened Supported Catalysts

“…Briefly, the production rate and selectivity of HCOOH on Pd 0.25 /WO 3 in 5 h are up to 4.67 mmol g cat –1 h –1 and 62%, respectively. These values are significantly higher than the performance of all of the state-of-the-art photocatalytic methane oxidation systems that use O 2 as an oxidant at room temperature (Figure d), and even surpassing the performance at elevated temperatures (orange part). ,,− …”

Electrostatic Assembly of Photochromic TiO2/Phosphomolybdic Acid Composite Nanoparticles for Light-Responsive Rewritable Papers

“…38,39 Moreover, the PMoA clusters are difficult because of their ultrasmall size and low amount. 40,41 The survey X-ray photoelectron spectroscopy (XPS) spectrum of S3). The Ti 2p spectrum shows two strong peaks at 458.6 and 464.4 eV for Ti 2p 3/2 and Ti 2p 1/2 , respectively (Figure 2d).…”

“…21-1272) (inset in Figure b). The HRTEM image of the composite nanoparticles shows a lattice spacing of 0.352 nm, which is assigned to the (101) plane of anatase phase TiO 2 (Figure c). , Moreover, the PMoA clusters are difficult because of their ultrasmall size and low amount. , The survey X-ray photoelectron spectroscopy (XPS) spectrum of TiO 2 /PMoA composite nanoparticles shows Ti, Mo, P, O, and C signals, which are from the TiO 2 nanoparticles and PMoA (Figure S3). The Ti 2p spectrum shows two strong peaks at 458.6 and 464.4 eV for Ti 2p 3/2 and Ti 2p 1/2 , respectively (Figure d).…”

Recent Advances in Confining Polyoxometalates and the Applications

“…[4,5] They have excellent photosensitivity, adjustable energy band structure, and wide absorption range, which endow them with excellent photochemical properties. [6,7] POMs can be regarded as weak Lewis bases due to the large number of surface oxygen atoms capable of binding Lewis acids. [8][9][10] The metal ions on the POM framework have empty orbitals, so they can also serve as Lewis acid issues.…”