CO coverage on Pd catalysts accelerates oxygen removal in oxy-combustion systems.

Oxy-combustion systems result in enriched CO in exhaust gases; however, the utilization of the concentrated CO stream from oxy-combustion is limited by remnant O. CH oxidation using Pd catalysts has been found to have high O-removal efficiency. Here, the effect of excess CO in the feed stream on O removal with CH oxidation is investigated by combining experimental and theoretical approaches. Experimental results reveal complete CH oxidation without any side-products, and a monotonic increase in the rate of CO generation with an increase in CO concentration in the feed stream. Density-functional theory calculations show that high surface coverage of CO on Pd leads to a reduction in the activation energy for the initial dissociation of CH into CH and H, and also the subsequent oxidation reactions. A CO-rich environment in oxy-combustion systems is therefore beneficial for the reduction of oxygen in exhaust gases.