Incorporation of silver into a Zr-CPEB metal-organic framework to enhance the electrocatalytic activity of hydrogen evolution reaction (HER)

Abstract

Ag@Zr-CPEB composite was synthesized by the incorporation of Ag metal into the Zr-CPEB metalorganic framework. The Zr-CPEB was synthesized from Zr(IV) salt and 1,4-bis(2-[4-carboxyphenyl]ethynyl) benzene (H2 CPEB) linker by the solvent-thermal method. Ag metal was incorporated in Zr-CPEB via a two-step process, including (i) absorption of Ag(I) ions into the Zr-CPEB and (ii) reduction of the Ag(I) ions to Ag by NaBH4 . The structure of Zr-CPEB was studied by Powder X-Ray Diffraction (PXRD). The presence of Ag in the composite was investigated by UV-Vis spectroscopy, FESEM energy dispersive X-ray (EDX), and TEM methods. Electro-catalytic properties of the Zr-CPEB support and Ag@Zr-CPEB composite were examined by the cyclic voltammetry (CV) method in 0.5 M Na2 SO4 (pH 7.2) aqueous solution. The results showed that the amount of Ag in the as-prepared composite was ca. 2% wt. Ag had increased the catalytic activity of the composite for the hydrogen evolution reaction (HER). The current density (at 850 mV/RHE) for HER of the Ag@Zr-CPEB composite was increased by 2.5 times compared to that of Zr-CPEB