The ecological environment is currently at risk due to increased carbon dioxide emissions. To save our beautiful planet, there is a global call to reduce fossil energy consumption by adopting alternative renewable energy sources. Specifically, hydrogen, a clean energy carrier, has been regarded as a promising candidate in the development of renewable energy technology. Splitting of water by hydrogen evolution reaction is one of the widely and eco-friendly used methods to produce hydrogen. This process requires suitable, efficient and stable catalysts such as platinum. However, the scarcity and high cost of these natural resources limit their practical applications. As such, great efforts have been made to explore new catalytic materials.
In a recently published literature, group-III monochalcogenides have been identified as potential active and stable catalysts for hydrogen evolution reaction due to their excellent electron and hole mobilities. InSe being a prototype of the two-dimensional materials is currently on the scientist’s radar. However, limited information is available regarding their reaction mechanism and reaction pathways as a catalyst in hydrogen evolution reactions. Based on the past reviews on two-dimensional nanoribbons, researchers revealed that their structures can accommodate more edge states and thus effective for studying the reaction mechanism in InSe catalysts.
Inspired by these insights, researchers at the Hebei University of Technology: Xiangrong Cheng, Changcheng Zhang, Dr. Lixiu Guan and led by Professor Junguang Tao investigated the hydrogen evolution reaction active sites of zigzag InSe nanoribbons. Specifically, the edge-enhanced electrocatalytic properties of one-dimensional InSe nanoribbons were evaluated based on first-principles calculations. The concept was illustrated by calculating the hydrogen adsorption energies in four configurations: In atoms, Se atoms, In vacancies and Se vacancies. Their research work is currently published in the International Journal of Hydrogen Energy.
For all the considered configurations, hydrogen absorption was observed to be an endothermic process on the surface and all the affinities of the hydrogen on the surface were somehow weak. The hydrogen evolution reaction activity was highly influenced by their edge states. Additionally, the electronic interaction between the H, In and Se atoms enhanced the band gap states. The interactions resulted in electron accumulation at H adsorption sites thus improving the hydrogen evolution reaction performance. Therefore, during the hydrogen evolution process, the charge transfer weakened the hydrogen adsorption hence reducing its desorption energy.
The findings confirmed that the localized bonding played an important role in promoting the hydrogen evolution activities. Generally, configurations without defects are expected to exhibit high hydrogen evolution reaction activities. As such, it was worth noting that their performances could be improved further by introducing in-plane vacancies. The results are beneficial to these kinds of experiments considering that they require addition of defects during experiments.
In summary, Hebei University of Technology scientists presented the first principle study of the hydrogen evolution activity on the InSe nanoribbons. The InSe nanoribbons both with and without defects exhibited impressive catalytic abilities. The results have seen the InSe nanoribbons being selected by the Advances in Engineering as a promising one-dimensional catalyst in the hydrogen evolution process. Professor Junguang Tao, the corresponding author noted that their results in hydrogen generation as a tool for the development of renewable energy technology.
Cheng, X., Zhang, C., Guan, L., & Tao, J. (2019). Origin of high hydrogen evolution activity on InSe nanoribbons: A first-principles study. International Journal of Hydrogen Energy, 44(44), 24174-24183.