Highly Efficient Bimetallic Catalysts Supported on Carbon Nanotubes for the NOx Reduction

TL;DR

This study develops a carbon-based bimetallic catalyst that efficiently reduces nitrogen oxides (NOx) at high temperatures, offering a promising alternative to traditional pollution control methods.

Contribution

The novel contribution is the development of a highly efficient bimetallic catalyst (Cu and K on N-doped carbon nanotubes) for NOx reduction with low N2O byproducts.

Findings

CNT_M_BM@5Cu5K achieved complete NO reduction at 360 °C with CO2 and N2 as main products.

The catalyst showed deactivation after 41 hours of continuous operation.

Low levels of N2O were produced compared to N2 and CO2.

Abstract

Nitrogen oxides represent a major source of concern related to atmospheric pollution, causing substantial impacts on human health. One innovative approach to reducing these emissions, and a promising alternative to conventional methods using NH3, is selective catalytic reduction with carbon (SCR-C). The aim of this study is the development of carbon-based catalysts that are active in the reduction of NO. For that, carbon nanotubes were subjected to treatments to modify their surface chemistry, including introducing oxygen and nitrogen groups, as well as potassium (K) and copper (Cu) incorporated as metal phases. In their original form, carbon nanotubes do not exhibit catalytic activity in reducing NO. However, catalytic performance is significantly improved by the addition of surface groups and Cu. Adding K to the support notably contributes to increasing the catalytic performance. N-doped carbon nanotubes impregnated with copper and potassium (CNT_M_BM@5Cu5K) achieved complete NO reduction at 360 °C. In this catalytic system, the formation of CO2 and N2 was observed and CO was not identified. Furthermore, although N2O was detected during the reaction, its amount was very low compared to the N2 and CO2 products. The stability of this catalyst was investigated over 87 h continuous test, revealing deactivation after 41 h of reaction.

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