Photocatalytic Chlorination of Methane Using Alkali Chloride Solution

Abstract

The development of direct conversion for selective functionalization of inert methane plays an important role in the chemical sciences. Here, we report a photocatalytic approach to successfully convert methane into methyl chloride over NaTaO3 photocatalyst using an alkali chloride solution as the chlorine source under ambient conditions, which can overcome disadvantages of toxicity and corrosiveness in the traditional chlorination of methane. Various noble metals and oxide cocatalysts (Pt, Pd, Au, Ag, and Ag2O) and different chloride ion solutions (NaCl, KCl, LiCl, MgCl2, BaCl2, CaCl2, CuCl2, FeCl3, ZnCl2, etc.) are investigated to optimize the photocatalytic chlorination processes. Ag2O/NaTaO3 is the best photocatalyst, giving the maximum CH3Cl yield of 152 μmol g–1 h–1 in aqueous NaCl solutions and an apparent quantum yield of 7.2% under 254 nm monochromatic light irradiation. The target product CH3Cl is verified to be formed by a direct combination of the photoinduced species •CH3 and •Cl on the Ag2O surface. This work provides a meaningful approach for the conversion of methane into chloromethane under normal conditions.

A highly durable AgOx cluster/mesoporous TiO2 photocatalyst with synergistic effects induced superior H2 evolution and CO2 reduction

“…A coexisting Ag 2 O component has demonstrated a beneficial effect on the stability of the Ag–Ag 2 O based composite in air. 32…”

“…This may be a benefit from the coexistence of Ag 2 O and Ag within the AgO x species, where Ag 2 O functions as a stabilizing agent for the highly active metallic Ag. 32…”

“…A coexisting Ag 2 O component has demonstrated a benecial effect on the stability of the Ag-Ag 2 O based composite in air. 32 Photocatalytic HER performance of the ACTs was tested in a 10% methanol aqueous solution (Fig. 3 and S8 †).…”

Capturing Solar Energy for Cathodic Protection of Metals: The Life of Photoexcited Charge Carriers

“…In the marine environment, the deposition of catalysts that are capable of selectively oxidizing halogen ions such as Cl À with holes to Cl 2 or ClO À may be an ideal option. In such a scenario, the concentration of local Cl À ions, [122] which are the main cause of pitting corrosion of metals, can be decreased, and the produced Cl 2 or ClO À may suppress biofouling and degrade pollutants in seawater. [21,[123][124][125][126][127]…”

Engineering interface structures for heterojunction photocatalysts

“…1–4 One of the effective ways to achieve this goal is to simulate natural photosynthesis to transform the extensive, clean and inexhaustible solar energy into chemical energy for storage and utilization. Such artificial photocatalysis has shown a wide range of applications in some important areas, such as aquatic hydrogen production, 5 CO 2 fixation, 6 organic synthesis, 7 NH 3 synthesis 8 and decomposition, 9 methane coupling, 10 and pollution degradation. 11 Photocatalysts are the research core of artificial photocatalysis.…”