MOF-derived g-C3N4/ZnIn2S4 S-scheme heterojunction: Interface-engineering enhanced photocatalytic NO conversion
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Credit: HIGHER EDUCATON PRESS
Nitrogen oxides (NOx) are major contributors to air pollution, posing serious risks to human health and ecosystems. While photocatalytic oxidation offers a promising approach to remove low-concentration NO from the atmosphere, conventional catalysts often suffer from low efficiency and poor selectivity, frequently converting NO into more toxic byproducts like NO2.
In a study published in Acta Physico-Chimica Sinica, Professor Ge Lei and his team from China University of Petroleum (Beijing) designed a novel S-scheme heterojunction by integrating hollow tubular ZnIn2S4—derived from a metal-organic framework (MOF) precursor—with two-dimensional graphitic carbon nitride (g-C3N4). The optimized composite, labeled CN/ZIS-0.1, exhibited remarkable photocatalytic performance under visible light, achieving a NO removal efficiency of 67.29%, significantly surpassing that of pure g-C3N4 (41.41%) or ZnIn2S4 (27.8%) alone.
More importantly, the catalyst demonstrated high selectivity, converting 77.47% of NO into non-toxic nitrate, thereby minimizing the release of hazardous NO2. The composite also showed excellent stability over multiple reaction cycles.
Through a combination of photoelectrochemical tests, in-situ XPS, and density functional theory (DFT) calculations, the team revealed that an internal electric field formed at the CN/ZIS interface drives the directional migration of photogenerated electrons to g-C3N4 and holes to ZnIn2S4. This S-scheme charge transfer mechanism not only enhances carrier separation but also preserves strong redox potentials, facilitating the generation of key reactive species such as superoxide radicals (·O- 2) and holes (h+), which play critical roles in the selective oxidation of NO.
The hollow tubular structure of ZnIn2S4 also provides a large specific surface area and abundant active sites, further promoting NO adsorption and reaction kinetics.
This work highlights the potential of MOF-derived hollow structures coupled with 2D semiconductors in designing highly efficient and selective photocatalysts for air purification. It offers a feasible strategy for the rational construction of heterojunction-based materials for environmental remediation.
This work, entitled “MOF-derived g-C3N4/ZnIn2S4 S-scheme heterojunction: interface-engineering enhanced photocatalytic NO conversion”, was published in Acta Physico-Chimica Sinica (published on August 26, 2025).