With the rapid advancement of global science and technology and the increasingly prominent issues of resources and the environment, materials science, a core field driving social progress, is continuously giving birth to revolutionary new materials. Among them, Metal-Organic Framework (MOF) materials stand out from numerous counterparts by virtue of their unique structural advantages and outstanding performance. Since the concept of MOFs was first proposed in 1995, their highly tunable pore structures, ultra-large specific surface areas and excellent chemical stability have broken the constraints of traditional materials in structural design and functional expansion, ushering in a new era of precise material engineering.

Despite remarkable progress made by MOFs in designable pore architecture and functional diversity, bottlenecks still exist in their practical applications. For instance, some MOFs suffer from low density of surface active sites and poor electron transport capacity, which readily trigger carrier recombination during photocatalysis and electrocatalysis. Meanwhile, their structural stability and activity retention under complex reaction environments or long-term operation need to be further improved. Against this backdrop, Low Temperature Plasma (LTP), an emerging surface modification strategy, has been gradually introduced into research on MOF modification. Rich in high-energy electrons, ions and reactive free radicals, low-temperature plasma interacts with material surfaces at near-room temperature to introduce structural defects, reconstruct chemical bonds and regulate surface functional groups, without damaging the overall crystalline framework of MOFs. This characteristic endows it with inherent advantages in overcoming drawbacks of conventional high-temperature treatment, such as metal agglomeration and pore collapse.

Applications of Low-Temperature Plasma Modified MOF Materials

Plasma is recognized as the fourth state of matter, distinct from solids, liquids and gases. It refers to an ionized gaseous state formed under specific conditions, which is electrically neutral as a whole and composed of charged ions, electrons and neutral particles. The term "low-temperature plasma" is coined to distinguish it from high-temperature plasma generated by thermonuclear fusion at temperatures up to 100 million degrees Celsius. Low-temperature plasma ranges from 300 K to 10⁵ K, and can be further classified into thermal plasma and cold plasma based on temperature and thermodynamic equilibrium. Thermal plasma has an apparent temperature of several thousand degrees, while cold plasma is usually slightly warmer than ambient temperature. High-temperature plasma is barely applicable in conventional laboratories and industrial scenarios, whereas low-temperature plasma boasts a wide range of usable applications.

Low-temperature plasma surface modification technology can improve material hydrophilicity, inter-material adsorption, adhesion and compatibility. Modification performance can be optimized by adjusting process parameters to obtain well-modified materials. The treatment is pollution-free with no byproducts generated, and only acts on the material surface layer, thus possessing broad prospects for modification of polymer materials.

Low-temperature plasma modification of Metal-Organic Frameworks has become a research hotspot in materials science in recent years. The interactions between high-energy plasma species and MOF surfaces enable precise tuning of pore structure, surface chemical properties and active sites, thereby drastically boosting their performance in catalysis, adsorption and organic synthesis.

The essence of plasma modification lies in the interactions of high-energy electrons, ions and reactive free radicals with material surfaces, which induce defect generation, surface chemical bond reconstruction and localized electronic structure modulation.

Existing studies demonstrate that different plasma gas atmospheres exert profound influences on the structural evolution pathways of MOFs. As summarized in Table 1, inert gas plasma mainly promotes defect exposure via physical bombardment and energy transfer, while reactive gas plasma can introduce oxygen vacancies, nitrogen dopants or surface functional groups to modulate metal coordination environments and electronic structures. 

Plasma modification synergistically enhances interfacial chemistry and functional performance of MOFs through surface functionalization, defect engineering and electronic structure regulation, while maintaining the integrity of their bulk crystalline frameworks.

As a green, high-efficiency and highly controllable surface modification technique, low-temperature plasma technology holds irreplaceable value for performance optimization and functional expansion of MOFs. Current research achievements have laid a solid foundation for the practical deployment of MOFs across multiple fields. Nevertheless, challenges remain in large-scale fabrication, energy consumption control and process formulation, and the stability and repeatability of modified MOFs under practical complex conditions require further evaluation. Future research can integrate multi-dimensional MOFs, MOF composites and eco-friendly plasma treatment to strike an optimal balance among performance, structural stability and scalable production. This will further broaden the practical application scope of plasma-modified MOFs in environmental remediation, energy conversion, catalytic chemical engineering and other sectors, providing critical material support for technological breakthroughs in environmental, energy and catalytic industries.