Hydrogen and oxygen fuel cells are expected to play an important role in the national dual carbon strategy due to their advantages of high specific energy and zero emissions. However, commercial platinum-carbon catalysts can easily adsorb carbon monoxide in hydrogen fuels and cause toxic shock. Especially in alkaline membrane fuel cells, the hydrogen oxidation kinetics of platinum-based catalysts is slow, and its synergistic effect with carbon monoxide toxication accelerates the degradation of battery performance. Therefore, the design and creation of a new anode catalyst with high activity and high resistance to carbon monoxide poisoning is a problem that needs to be solved in the practical application of alkaline membrane fuel cells.
Recently, Professor Gao Minrui’s research group of University of Science and Technology of China and Professor Yang Qing’s research group cooperated to create a low-cost, carbon-monoxide resistant non-noble metal hydroxide catalyst by introducing a small amount of cobalt to improve molybdenum-nickel alloy catalyst. The results were published in German Applied Chemistry and selected as VIP papers and frontispiece illustrations.
The research results were selected as VIP papers and frontispiece illustrated papers Courtesy of University of Science and Technology of China
Theoretical calculation studies have found that the introduction of cobalt into molybdenum-nickel alloy significantly reduces the carbon monoxide adsorption energy at the nickel site. This is because the introduction of cobalt will bring about electron-deficient nickel sites, which weakens the electron “reverse supply” of nickel’s d orbital to 2π* of carbon monoxide, which is conducive to reducing the adsorption capacity of the catalyst to carbon monoxide. The state density map combined with a series of electronic structure characterization revealed that the d-band center of a small amount of cobalt-modified molybdenum-nickel alloy catalyst is far away from the Fermi level, and the electron “reverse supply” cannot occur effectively, which is expected to bring high carbon monoxide tolerance.
Rotating disc electrode tests have shown that when hydrogen fuel contains 500ppm carbon monoxide, the activity of the catalyst is almost not attenuated after 10,000 cycles.
The researchers further investigated the catalyst’s resistance to carbon monoxide toxication under membrane electrode assembly and found that even in hydrogen fuel containing 250 ppm carbon monoxide, a small amount of cobalt-modified molybdenum-nickel alloy catalyst provided a peak power density of 394 milliwatts per square centimeter, exceeding the 209 milliwatts per square centimeter of commercial platinum-carbon catalysts. In pure hydrogen fuel, the peak density of the catalyst can reach 525 milliwatts per square centimeter, which is in the forefront of non-precious metal catalysts. (Source: Wang Min, China Science Daily)
Related Paper Information:https://doi.org/10.1002/anie.202284262