Mechanistic Insights into Evolution of Schottky Junctions on Metal Nanoparticle-Loaded Mo-Doped Tio2 for Enhanced Photothermal Ammonia Catalysis

Abstract

Ammonia (NH3) is a hazardous pollutant that poses significant health and environmental risks, necessitating efficient removal strategies. Schottky junction-enhanced photothermal catalytic oxidation offers a promising approach to address the limitations of conventional photocatalysis, including low solar energy utilization and suboptimal catalytic performance. Here, metal nanoparticles (Ni, Pd, Pt, Au, Ag) were loaded onto Mo-doped TiO2 to construct Schottky junctions, resulting in significantly improved NH3 oxidation performance. Notably, Pt uniquely outperformed other metals due to its exceptional stability in maintaining a metallic state even after prolonged exposure. In-situ DRIFTS analysis revealed a distinct ·NH2 pathway for NH3 oxidation on Pt/Mo-TiO2, differing from mechanisms observed in other metal-loaded catalysts. Combined experimental findings and DFT analyses provided direct evidence of the relationship between chemical states of metals, Schottky junction formation, and enhanced electron-hole separation. This study offers valuable theoretical insights into Schottky junction-enhanced photothermal catalysis and highlights its potential for efficient NH₃ removal under solar irradiation.

Keywords: Schottky junction, Photothermal catalytic oxidation, NH3 removal, Mo-doped TiO2