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.

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The high inertness of the C−H bond makes the photocatalytic methane conversion a significant challenge. The platinum nanoparticle is a promising cocatalyst for CH 4 activation, while the study of its structure characteristics and functionality remains in its infancy. Herein, the size effect of Pt on the photocatalytic nonoxidative methane conversion efficiency was systematically investigated over x-Pt/Ga 2 O 3 with the particle size (x) ranging from 1.5 to 2.7 nm, where a volcano-shaped relation was observed. The smaller size is beneficial to the formation of Pt δ+ species, which is mainly distributed on the terrace sites according to the DFT calculation. The corner Pt atom is the geometric active site for the CH 4 polarization, and the terrace Pt δ+ helps promote C−H activation since the activity is decreased on reduced x-Pt/ Ga 2 O 3 with a lower Pt δ+ content. Meanwhile, Pt δ+ species favors the oxidation of adsorbed −CH 3 group to •CH 3 . The volcanoshaped size effect on the NOCM activity was finally rationalized by the balance between C−H activation and C 2 H 6 desorption from the corner sites on different sized Pt.

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.

Although it is well-known that the size can influence the surface plasmon resonance property of coinage metals and the electronic state of the Mott–Schottky junction formed at the metal/semiconductor interface, insights into how the size can be exploited to optimize the photocatalytic activity and selectivity of metal/semiconductor composites are lacking. Here we utilize operando SERS spectroscopy to identify the size effect on the electron-transfer dynamics and the direction at the Au/TiO2 interface. This effect was characterized by the photocatalytic reduction sites of p-nitrothiophenol, which were self-tracked with the SERS spectra from Au nanoparticle and inverse-opal structured TiO2, respectively. The size-dependent unidirectional/bidirectional transfer of photoinduced electrons at the Au/TiO2 interface was revealed by operando SERS spectroscopy, which enables the rational tuning of the reduction selectivity.