Scientists at the Swiss Federal Institute of Technology in Lausanne (EPFL) have synthesized the first-ever metal-organic frameworks (MOF) membrane with a thickness of just one unit cell. The ultrathin film yields record-high separation performance of hydrogen.
MOFs are a class of materials that contain nano-sized pores. These pores give MOFs record-breaking internal surface areas, which make them extremely versatile for a number of applications, including gas separation, energy storage, and catalysis.
In the gas-separation domain, MOFs are particularly interesting for separating hydrogen from nitrogen, which is crucial for clean energy production, fuel cell efficiency, ammonia synthesis, and various industrial processes. Hydrogen-nitrogen separation also has a number of environmental benefits, making it integral to advancing sustainable technologies and industrial practices.
The new ultrathin MOF membrane developed by EPFL scientists could revolutionize hydrogen separation. The film is just two nanometers thick, but it has a unique configuration that allows for an exceptional combination of hydrogen flux and selectivity.
To make the films, the researchers used an innovative crystallization method that capitalizes on the precise alignment of ultra-dilute precursor mixtures with the underlying crystalline substrate. By carefully controlling precursor concentrations and interactions with the substrate, the team were able to suppress out-of-plane growth – a common problem in making thin films.
The approach paid off: Within a matter of minutes, and at room temperature, the scientists were able to fabricate macroscopically uniform two-dimensional (2D) ZIF films with unprecedented thickness: just one structural unit, measuring only two nanometers. The scientists also showed that the process is scalable preparing films with area of hundreds of square centimeters. The breakthrough overcomes conventional methods, which have limited ZIF film thickness to 50 nanometers, making their widespread use difficult.
The new ZIF film has the potential to significantly improve the efficiency and cost-effectiveness of hydrogen separation. The film’s unique configuration allows for much higher hydrogen flux than conventional MOF membranes, while maintaining high selectivity. This could lead to significant reductions in the energy required for hydrogen purification, as well as smaller and more efficient hydrogen production and storage systems.
The EPFL scientists’ breakthrough is a major step forward for the development of MOF membranes for gas separation. The ultrathin ZIF film has the potential to revolutionize hydrogen separation and other industrial processes that require high-purity hydrogen.
The new ultrathin MOF membrane developed by EPFL scientists could have a significant impact on a number of industries. The film’s potential to improve the efficiency and cost-effectiveness of hydrogen separation could lead to wider adoption of hydrogen as a clean energy source. The film could also be used to improve the efficiency of other industrial processes that require high-purity hydrogen, such as ammonia synthesis and fuel cell production.
In addition to its potential applications in hydrogen separation, the new MOF membrane could also be used to separate other gases, such as carbon dioxide and methane. This could have important implications for carbon capture and storage (CCS) technologies, which are essential for reducing greenhouse gas emissions.
