Unlocking Catalytic Efficiency: How Preparation Strategies and Copper Loading Enhance Hydroxyapatite Catalysts for NH3 Oxidation
Year: 2025
Type: article
Abstract: The Selective Catalytic Oxidation of ammonia (NH₃-SCO) is gaining attention due to the hazardous nature of NH₃ and its inclusion in emission reduction frameworks such as the National Emission Ceilings Directive and the Gothenburg Protocol (1999). Copper-based hydroxyapatite (Cu/HAP) catalysts have emerged as a promising solution, offering high activity and cost-effectiveness.This study evaluates two preparation methods: a one-pot co-precipitation technique and post-synthesis copper deposition, varying contact time and copper concentration. The influence of copper loading and preparation method on catalyst performance in NH₃-SCO was investigated in a continuous flow reactor over a temperature range of 200–500°C, with a fixed gas hourly space velocity (GHSV) of 120,000 h⁻¹ and an NH₃/O₂ ratio of 0.03.X-ray diffraction and DR-UV spectroscopy confirmed the high crystallinity of HAP and provided insights into copper speciation. X-ray photoelectron spectroscopy revealed that Cu/HAP catalysts prepared via one-pot co-precipitation predominantly contained isolated Cu²⁺ species, which were associated with high catalytic activity in selective NH₃-SCO. Conversely, a higher degree of copper structuring was observed in catalysts prepared by post-synthesis deposition, particularly at higher Cu loadings.These findings highlight the potential to tailor Cu structuring on HAP to enhance performance in NH₃-SCO through optimized preparation strategies.
Source: Catalysts
Institution: University of Milan
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,654
Awards: G1795415632, G503275742, G5499711475
OpenAlex ID: W4409634027