Exhaust gas recirculation cooler barrier layer

Aspects of the disclosure relate to providing an EGR cooler including a barrier layer applied to EGR cooler components while allowing sufficient heat transfer between exhaust gases and the cooling medium. A barrier layer may be applied onto particular surfaces of the EGR cooler components to prevent deposition of hydrocarbons or soot on the EGR cooler components. In some arrangements, the barrier layer may comprise a refractory solid oxide. In other arrangements, an EGR cooler may comprise a catalytic barrier layer. The catalytic barrier layer may include a refractory solid oxide and a platinum group metal or mixed metal oxide to prevent accumulation of varnish material deposited onto EGR cooler components.