Hongrun Zhu, Xinyao Zhang, Huiyue Wang, Guixin Hu, Lingling Feng, Qianyu Wei, Zhikun Dai, Xueying Wen*, Ran Niu*, Jiang Gong*
High-performance water evaporation-induced electricity generation by calcium-based metal-organic framework from waste phosphogypsum
Journal of Environmental Chemical Engineering (2026) accept. (IF2025 = 7.5)
Converting phosphogypsum into valuable metal-organic frameworks (MOFs) not only contributes to the upcycling of billions of tons of waste phosphogypsum, but also provides a new platform to construct low-cost, high-performance MOF-based generators. However, the underlying reaction pathways for the conversion of phosphogypsum into MOFs remain poorly understood, and the electricity generation mechanism is controversial. Herein, an organic solvent-free mechanochemical and water-assisted treatment strategy is reported to convert industrial waste phosphogypsum into Ca-based metal-organic framework (namely Ca-BDC), which is subsequently fabricated into Ca-BDC generator for water evaporation-induced electricity generation. During ball milling, a proposed carboxylate-containing precursor potentially involving Ca-BDC coordination is formed through the coordination between deprotonated terephthalate and Ca2+ from phosphogypsum, which is subsequently transformed into a long-range ordered framework during the water-assisted treatment. The resultant Ca-BDC generator delivers an open-circuit voltage of 360 mV in seawater, exhibiting competitive electricity-generation performance. Notably, by integration, Ca-BDC generator readily achieves a maximum voltage output of 7.5 V under outdoor conditions. The molecular dynamics simulation result indicates that the diffusion difference between Cl- and Na+ within Ca-BDC nanochannels in seawater leads to asymmetric ion migration and net charge accumulation at the two ends of the device, thereby generating an electrical potential. This work integrates waste utilization with interfacial energy harvesting, not only offering a green pathway for large-scale phosphogypsum recycling, but also providing mechanistic insight into metal-organic framework-enabled water evaporation-induced electricity generation.
Keywords: Phosphogypsum waste, metal-organic framework, water evaporation-induced electricity generation, ball milling, upcycling