On the possibility of a significant temperature gradient in supported metal catalysts subjected to microwave heating

A simple model is presented which estimates the temperature gradients in microwave-irradiated 1 and 100 nm metallic particles which are typically found in a supported metal catalyst structure. The two particle sizes allow limiting case calculations of the temperature rise over the range of typical particle sizes. The model, based on a simple steady-state energy balance, uses the assumption that the particles only lose heat to the gas-phase, and not the support matrix. This represents a best-case scenario for a temperature gradient relative to the surroundings. The model indicates that the temperature gradient is insignificant and this conclusion is supported by an experiment in which the microwave-driven carbon monoxide reaction acts as an in situ temperature probe.