An alternative low-cost, eco-friendly catalyst for hydrogen production

Hydrogen fuel is a promising carbon-free fuel alternative, but producing hydrogen sustainably is difficult. Currently, the most reliable method, water electrolysis, uses the hydrogen evolution reaction, or HER, with platinum as the best active electrocatalyst. However, platinum is rare and costly, making it a suboptimal choice, particularly on an industrial scale.

With the goal of finding stable, low-cost, environmentally friendly catalysts for large-scale hydrogen production, Sahoo et al. tested a new strategy to synthesize molybdenum disulfide, a leading alternative and non-metal electrocatalyst for HER.

Using a two-step hydrothermal technique, the molybdenum disulfide was dispersed in water with a surfactant that increased the production of layered nanosheets. A subsequent bath sonication helped break the nanosheets into nanocrystals. Rich with defects, these nanocrystals were found to be ideal HER catalysts.

“We are most excited about the electrochemical performance of noble metal-free catalysts, like low overpotential and small Tafel slope with an adequate amount of electrochemically active sites,” said coauthor Bhaskar Kaviraj. “In addition to this, the cycling stability of molybdenum disulfide nanocrystals over 3,000 cycles is also achieved in both alkaline and acidic mediums.”

By providing a low-cost alternative to platinum that is easy to produce, the improved molybdenum disulfide catalyst could ultimately help reduce the cost of hydrogen production while also providing an eco-friendly strategy of generating hydrogen by greener routes.

“We hope this work can provide new insights on further understanding of HER with molybdenum disulfide and give instructions for the experimental design and synthesis of other transition metal dichalcogenides-based high-performance catalysts,” Kaviraj said.

Source: “A simple two-step strategy to synthesize defect-rich MoS2 nanocrystals for enhanced electrochemical hydrogen evolution,” by Dhirendra Sahoo, Jyoti Shakya, Sudipto Choudhry, Budhi Singh, and Bhaskar Kaviraj, AIP Advances (2022). The article can be accessed at https://doi.org/10.1063/5.0083934 .