Method and catalyst article

A method for forming a catalyst article comprising: (a) forming a plastic mixture having a solids content of greater than 50 % by weight by mixing together a crystalline small pore molecular sieve in an H+ or NH4 + form, iron sulphate, an inorganic matrix component, an organic auxiliary agent, an aqueous solvent and optionally inorganic fibres; (b) moulding the plastic mixture into a shaped article; and (c) calcining the shaped article to form a solid catalyst body. The plastic mixture may preferably also contain inorganic fibres. Also disclosed is a catalyst article comprising a solid catalyst body which comprises an iron-loaded small pore molecular sieve and has a coefficient of thermal expansion (CTE) which is zero or positive at a temperature in the range of 100 - 700 °C.