Transport Mediating Core-Shell Photocatalyst Architecture for Selective Alkane Oxidation.

Xie, Chenlu; Sun, Eddie; Wan, Gang; Zheng, Jian; Gupta, Raghubir; Majumdar, Arun · Nano Lett · 2023

basic_science · Level V

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Abstract

The high activation barrier of the C-H bond in methane, combined with the high propensity of methanol and other liquid oxygenates toward overoxidation to CO<sub>2</sub>, have historically posed significant scientific and industrial challenges to the selective and direct conversion of methane to energy-dense fuels and chemical feedstocks. Here, we report a unique core-shell nanostructured photocatalyst, silica encapsulated TiO<sub>2</sub> decorated with AuPd nanoparticles (TiO<sub>2</sub>@SiO<sub>2</sub>-AuPd), that prevents methanol overoxidation on its surface and possesses high selectivity and yield of oxygenates even at high UV intensity. This room-temperature approach achieves high selectivity for oxygenates (94.5%) with a total oxygenate yield of 15.4 mmol/g<sub>cat</sub>·h at 9.65 bar total pressure of CH<sub>4</sub> and O<sub>2</sub>. The working principles of this core-shell photocatalyst were also systematically investigated. This design concept was further demonstrated to be generalizable for the selective oxidation of other alkanes.