Photocatalytic Nitrogen Oxide Removal Activity Improved Step-by-Step through Serial Multistep Cu Modifications

Area of Science:

• Materials Science
• Environmental Chemistry
• Catalysis

Background:

• One-step modified photocatalysts show insufficient efficiency for nitrogen oxide (NO) removal.
• Graphitic carbon nitride (g-C3N4) is a promising material for environmental remediation but requires optimization for NO removal.

Purpose of the Study:

• To explore serial multistep modification of g-C3N4 to improve its NO removal activity.
• To identify the active species and mechanisms responsible for enhanced NO removal.
• To establish serial multistep modification as a viable strategy for enhancing g-C3N4 photocatalysis.

Main Methods:

• Serial multistep modification of g-C3N4 with copper elements in a continuous process.
• Characterization of modified photocatalysts to identify structural and chemical changes.
• Analysis of active species (h+, •O2-, •OH) and reaction mechanisms involved in NO removal.

Main Results:

• Serial multistep modification significantly improved the NO removal activity of g-C3N4.
• The main active species shifted from h+ and •O2- in pristine g-C3N4 to h+ and •OH in modified samples.
• Different copper modification steps facilitated NO removal via distinct mechanisms, including Fenton-like reactions and photoelectron activation of H2O2, with synergistic effects observed after the third modification.

Conclusions:

• Serial multistep modification of g-C3N4 with copper is an effective strategy for enhancing photocatalytic NO removal.
• The staged introduction of copper and subsequent modifications lead to the generation of crucial reactive species (•OH) and synergistic effects.
• This approach offers a promising pathway for developing highly efficient g-C3N4-based photocatalysts for environmental pollutant removal.