Catalytic Reduction of Nitric Oxide with Hydrogen Using Carbon-Supported d-Metal Catalysts

Abstract

Technologies for the reduction of nitric oxide are well established and are a critical resource in reducing the emission of nitrogen oxides released during combustion. Herein, we demonstrate a more sustainable approach, utilising Earth-abundant metals supported on waste-derived carbon to facilitate this reaction. Selective catalytic reduction, whereby a reductant is used to convert NO over a catalytic bed into nitrogen, is regarded as the best available technology for NO reduction. Here, we have investigated the use of H2, which has the potential to be produced from sustainable resources, as the reductant. Three selected d-metals (copper, iron and manganese) were impregnated over palm kernel shell activated carbons via incipient wetness. The characteristics of the carbon support and the derivative catalysts were analysed to investigate structure-performance relationships. H2-SCR was performed in a fixed-bed reactor; the results showed that the supported-copper catalyst converted NO completely at temperatures of 250 °C and above. This is attributed to the high reducibility and acidity of the catalyst as demonstrated via temperature-programmed reduction, ammonia-temperature programmed desorption, Fourier-transform infra-red spectroscopy and nitric oxide adsorption–desorption experiments. It is concluded that the carbon-supported d-metal catalysts are viable for use in H2-SCR, thereby promoting a more sustainable approach to mitigating NOx emissions.Graphic Abstract