Ga-Doped and Pt-Loaded Porous TiO2–SiO2 for Photocatalytic Nonoxidative Coupling of Methane

Authors:
Top Cited Papers
Publisher website
Google Scholar
Abstract
Photodriven nonoxidative coupling of CH4 (NOCM) is a potential alternative approach to clean hydrogen and hydrocar-bon production. Herein, a Mott-Schottky photocatalyst for NOCM is fabricated by loading Pt nanoclusters on a Ga-doped hierarchical porous TiO2-SiO2 microarray (HGTS) with an anatase framework, which exhibits a CH4 conversion rate of 3.48 µmolg-1h-1 with 90% selectivity towards C2H6. This activity is 13 times higher than those from microarrays without Pt and Ga. Moreover, a continuous H2 production (36 µmolg-1) with a high CH4 conversion rate of approx. 28% can be achieved through a longtime irradiation (32 h). The influence of Ga on the chemical state of a surface oxygen vacancy (Vo) and deposited Pt is investigated through a combination of experimental analysis and first-principles density functional theory calculations. Ga substitutes for the five-coordinated Ti next to Vo, which tends to stabilize the single-electron trapped Vo and reduce the electrons transfer from Vo to the adsorbed Pt, resulting in the formation of a higher amount of cationic Pt. The cationic Pt and electron-enriched metallic Pt form a cationic-anionic active pair, which is more effi-cient for the dissociation of C-H bonds. However, the presence of too much cationic Pt results in more C2+ product with a decrease in the CH4 conversion rate due to the reduced charge-carrier separation efficiency. This study provides deep insight into the effect of the doping/loading strategy on the photocatalytic NOCM reaction and is expected to shed sub-stantial light on future structural design and modulation.
Funding Information
  • National Natural Science Foundation of China (21673073, 21677048, 5171101651)
  • Science and Technology Commission of Shanghai Municipality (16JC1401400, 17520711500, 18520710200, 18PJD012)
  • PetroChina Innovation Foundation (2015D-5006-0402)
  • Ministry of Education of the People's Republic of China (222201717003, 22221818014)

This publication has 44 references indexed in Scilit: