Single-Atom Ni Catalysts Enable a Cl-Shift Pathway for Low-Temperature Chlorobenzene Decomposition

Area of Science:

• Environmental Chemistry
• Catalysis
• Materials Science

Background:

• Municipal solid waste incineration produces flue gases containing chlorobenzenes (CBzs).
• Effective air pollution control requires low-temperature catalytic decomposition of CBzs (120-180 °C).
• Catalyst mechanisms for CBz decomposition at low temperatures are not fully understood.

Purpose of the Study:

• To elucidate the decomposition mechanism of chlorobenzenes (CBzs) using a nickel single-atom catalyst (Ni@rGO) at low temperatures.
• To investigate the role of catalyst structure and coordination in enhancing CBz degradation.
• To demonstrate the efficiency of Ni@rGO for air pollution control.

Main Methods:

• Utilized a nickel single-atom catalyst supported on reduced graphene oxide (Ni@rGO) as a model system.
• Investigated chlorobenzene (CBz) degradation at 150 °C.
• Employed Density Functional Theory (DFT) calculations to analyze reaction mechanisms and coordination chemistry.

Main Results:

• CBz degradation at 150 °C proceeds via hydrodechlorination coupled with a significant Cl-shift rearrangement within the CBz molecule.
• The Cl-shift mechanism, driven by Ni-CBz η²-C coordination, optimizes adsorption and stabilizes the aromatic ring.
• Ni@rGO achieved 98.6% CBz decomposition efficiency at 150 °C with minimal nickel loading.

Conclusions:

• A novel Ni single-atom-driven Cl-shift mechanism accelerates low-temperature chlorobenzene (CBz) decomposition.
• This mechanism enhances catalyst performance by optimizing adsorption and stabilizing intermediates.
• Ni@rGO shows high potential for efficient air pollution control in waste incineration.