A water-stable La-MOF with high fluorescence sensing and supercapacitive performances.

A 3D lanthanide coordination polymer {[La(SIP)(HO)]·HO} (La-MOF) was synthesized successfully by the solvothermal reaction of La(NO)·6HO and 5-sulfoisophthalic acid monosodium salt (NaHSIP). In particular, two oxygen atoms of sulfate participate in the coordination, which is unusual in all the complexes. La-MOF was characterized by single-crystal X-ray diffraction, IR spectroscopy, powder X-ray diffraction, thermal-gravimetric analysis, and X-ray photoelectron spectroscopy. La-MOF shows excellent water stability and chemical stability in a broad pH range from 2 to 13. Moreover, the fluorescence and sensing properties of La-MOF were invsetigated in detail via its titration and cycling processes, revealing its highly efficient and selective quenching responses and good recyclability for the detection of Fe, CrO and CrO ions. In addition, La-MOF possesses an outstanding specific capacitance of 213 F g at 0.5 A g. It still retains 92% of the original capacitance after 2000 cycles, exhibiting remarkable long-term cycling stability and reversibility; therefore, the electrode material based on La-MOF is a competitive and promising candidate for application in supercapacitors.