In6S7 nanoparticle-embedded and sulfur and nitrogen co-doped microporous carbons derived from In(tdc)2 metal–organic framework

Abstract

Indium sulfide nanoparticle (NP)-embedded microporous carbons co-doped with S- and N-dopants are easily prepared by a direct carbonization of the as-prepared In(III)-based metal–organic framework (In-MOF), [Et₂NH₂][In(tdc)₂]·DEF, containing ditopic S-containing 2,5-thiophenedicarboxylate (tdc²⁻) bridging linkers as a potential source of S-dopant. The charge on the anionic framework of [In(tdc)₂]⁻ is balanced by Et₂NH₂⁺, which is also a potential N-dopant. Simultaneous embedding of In-based NPs, S-, and N-co-doping is achieved in a simple single step carbonization of In-MOF. Three porous carbon materials (PCMs), PCM-700, PCM-800, and PCM-900, are obtained from the carbonization of In-MOF at 700, 800, and 900 °C, respectively. The gas sorption analysis indicates them as good CO₂ sorbents. The photocatalytic degradation of methyl orange by PCMs under visible light irradiation is also effectively operable owing to the photocatalytically active semiconducting indium sulfide NP with a small bandgap. The main component of indium sulfide NPs is revealed as In₆S₇ based on the powder X-ray diffraction pattern. Small amounts of metallic In and In₂S₃ are also observed. The specific capacitances of PCMs are also estimated from the galvanostatic charge/discharge curves. PCM-900 exhibits the highest gravimetric specific capacitance of 99.0 F g⁻¹ at a current density of 0.05 A g⁻¹.