Researchers develop efficient catalyst fuel cell that can run stably for at least 180 hours

(Photo source: greencarcongress)

According to foreign media reports, an international research team synthesized a one-dimensional string-like platinum-nickel alloy nanocage with a platinum skin structure, which is used as a catalyst for oxygen reduction reaction in fuel cells. The mass activity of this nanocage catalyst is as high as 3.52 amperes per milligram of platinum, and the specific activity is also very high, reaching 5.16 amperes per square centimeter of platinum, which are almost 17 times and 14 times that of commercial platinum-carbon catalysts, respectively.

The catalyst showed high stability after 50,000 cycles with almost no activity decay. Experimental results and theoretical calculations show that there are fewer strongly bonded platinum oxygen sites due to strain and ligand effects. With the support of this catalyst, the fuel cell has a current density of 1.5A/cm2 at a voltage of 0.6V and can operate stably for at least 180 hours.

In fuel cells and metal-air batteries, platinum is the most active oxygen reduction reaction electrocatalyst with good stability. However, even the most advanced platinum catalysts are still insufficient in terms of cost and large-scale commercial applications. Using the near-surface structure of nano-platinum alloys to improve the electrocatalytic performance of platinum-based electrocatalysts is a very promising approach to maximize the discovery of highly active sites with optimal performance. The researchers stated: "The addition of other transition metals to adjust the binding strength of platinum-oxygen intermediates through ligand and strain effects can improve catalyst performance. The introduction of open nanostructures such as hollow and porous nanoparticles, such as nanocages and nanoframe structures, can help achieve this goal and enhance mass transfer."

To prepare the nanocages, the research team first prepared 1D string-like platinum-nickel alloy nanocages (BNSs) by reducing platinum and nickel precursors in different ratios through a one-pot solvothermal method. The nickel species were selectively removed under acidic conditions, leaving ultrathin-walled 1D Pt-Ni BNCs composed of a platinum skin and residual platinum-nickel alloy.

The researchers said: "This study provides an effective strategy for the rational design of platinum alloy nanostructures, which will help provide guidance for the practical application of catalysts in areas such as energy conversion."