Effects of carbon monoxide on proton exchange membrane fuel cells and elimination techniques

Proton exchange membrane (PEM) fuel cells require high-purity hydrogen. Carbon monoxide (CO) is a common impurity in hydrogen that significantly reduces the performance of PEM fuel cells. Currently, there are two main methods to eliminate the effect of CO: direct removal of CO and increasing the CO tolerance of PEM fuel cells. Each method has its advantages and disadvantages. It is important to consider the specific application when choosing between these methods. This review summarizes the mechanism of CO poisoning and its effect on the operation and durability of PEM fuel cells, as well as hydrogen purification and CO-tolerant techniques. Then analyzes the advantages and disadvantages of commonly used techniques and predicts future research directions for PEM fuel cells using impure hydrogen containing CO, aiming to expand the application scenarios, and promote the large-scale application of PEM fuel cells.