SCR catalyst for Hg oxidation

Johnson Matthey’s advanced SCR catalysts can achieve high Hg0 conversions under a variety of power plant conditions for cleaner energy and cleaner air.

Mercury is one of the most volatile of all the heavy elements and is known for its toxicity, particularly in the form of methyl mercury. The US Environmental Protection Agency‘s recent regulations (Mercury and Air Toxics Standards, MATS) are heavily focused on Hg removal from coal-fired and oil-fired power plants. In order to meet this requirement utility companies have been required to either install advanced emission control technology or shutdown the power plant. One common approach is to use existing emission control technology for NOx and SOx removal to obtain a co-benefit for Hg removal. This is done by using the Selective Catalytic Reduction (SCR) catalyst to oxidise Hg from elemental Hg0 to oxidised Hg2+ that can then be more readily captured in the Flue Gas Desulphurization (FGD) unit.

Advantages of a co-benefits approach for Hg removal

  • No additional Hg specific technology needed
  • Existing controls technology can be used
  • No effect on gypsum by-product
  • Low OPEX and CAPEX costs


Although the co-benefits approach has several advantages, it does require a more in depth understanding of the Hg oxidation capabilities of the SCR catalysts and a more active catalyst management system. Johnson Matthey scientists have developed advanced characterisation and activity measurement techniques that can assess the performance of the SCR catalysts at near power plant operating conditions. Using these techniques, JM scientists have created models to help predict the maximum Hg oxidation potential for your SCR catalysts under a variety of power plant conditions. Johnson Matthey also offers advanced SCR catalysts with improved Hg oxidation capabilities at power plant conditions.


Johnson Matthey’s Hg oxidation SCR capabilities

  • Full assessment of the catalyst performance
  • Optimisation of the Hg potential
  • Strategies for maintain Hg oxidation performance
  • Advanced Hg oxidation SCR catalysts

General enquiries

Joseph McCarney

Betty Ann Keen