Non‐oxidative Coupling of Methane: N‐type Doping of Niobium Single Atoms in TiO₂–SiO₂ Induces Electron Localization

Abstract

Photodriven nonoxidative coupling of CH4 (NOCM) is an attractive potential way to use abundant methane resources. Herein, an n‐type doped photocatalyst for NOCM is created by doping single‐atom Nb into hierarchical porous TiO2–SiO2 (TS) microarray, which exhibits a high conversion rate of 3.57 μmol g−1 h−1 with good recyclability. The Nb dopant replaces the 6‐coordinated titanium on the (1 0 1) plane and forms shallow electron‐trapped surface polarons along [0 1 0] direction and the comparison of different models proves that the electron localization caused by the n‐type doping is beneficial to both methane activation and ethane desorption. The positive effect of n‐type dopant on CH4 conversion is further verified on Mo‐, W‐ and Ta‐doped composites. In contrast, the doping of p‐type dopant (Ga, Cu, Fe) shows a less active influence.

Photocatalytic CO2reduction on Cu single atoms incorporated in ordered macroporous TiO2toward tunable products

“…Therefore, various metal cocatalysts including noble metals, transition metals and rare Earth metals, have been prepared in SA sites to increase the photocatalytic efficiency. [8][9][10][11][12] Among them, copper (Cu) has been identified as one of the most promising cocatalysts to convert CO 2 into various hydrocarbons owing to its optimum binding ability with CO 2 and reaction intermediates. [13][14][15][16] The individual Cu atoms immobilized on light-harvesting semiconductors can act as excellent active sites for activating CO 2 molecules and stabilizing reaction intermediates in the photocatalytic CO 2 reduction reaction.…”

Design of frustrated Lewis pair in defective TiO2 for photocatalytic non-oxidative methane coupling

“…Photocatalytic non-oxidative coupling of methane (NOCM) is one of the effective approaches to selectively producing ethane and hydrogen under mild conditions [4][5][6][7] . Our previous work has veri ed that Pt δ+ -Pt pair loaded on TiO 2 can promote the photocatalytic C-H polarization at room temperature 5,8 .…”

High-energy Charge Separation State for Photocatalytic Nonoxidative Methane Conversion

“…16 In addition, the incorporation of some highly dispersed metal cations (Zn + , Ga 3+ , Ce 4+ , Nb 5+ ) into the supports is also an effective strategy to promote the activation of methane. [17][18][19][20] Another challenge constraining the development of e cient photocatalytic NOCM is the instability of the catalysts. 9 To date, only a few unsupported semiconductor photocatalysts can durably produce both ethane and H 2 under photocatalytic NOCM conditions.…”