Synthesis of high performance Ni3C-Ni decorated thermally expanded reduced graphene oxide (TErGO/Ni3C-Ni) nanocomposite: A stable catalyst for reduction of Cr(VI) and organic dyes

[Display omitted] •Synthesis of stable and porous thermally expended reduced-graphene oxide (TErGO/Ni3C-Ni) nanocomposite.•High performance reduction of Cr(Ⅵ) via TErGO/Ni3C-Ni nanocatalyst.•Fast reduction of dyes with the help of TErGO/Ni3C-Ni nanocatalyst. A high performance thermally expanded reduced graphene oxide (TErGO) nanocomposite decorated with Ni3C-Ni nanoparticles (TErGO/Ni3C-Ni) has been successfully synthesized by using a facile and eco-friendly approach. The morphology, textural features, surface composition and stability of TErGO/Ni3C-Ni nanocomposite are investigated by various physicochemical characterizations which revealed the uniform dispersion of crystalline metal nanoparticles inside TErGO matrix. The composite has been exhibited a large surface area and pore volume of 121 m2 g−1 and 0.791 cm3 g−1, respectively. The TErGO/Ni3C-Ni exhibited remarkable catalytic performance surpassing most metal-based catalysts with various kind of support matrices reported in recent literature. The reduction of Cr(Ⅵ) to Cr(Ⅲ) was achieved within 1 min with an excellent rate constant of 2.74 min−1 and phenomenally higher specific removal rate (SRR) of 0.29 mg Cr(VI) min−1. mg−1 of TErGO/Ni3C-Ni. While it also proved an excellent reducing catalyst for organic dyes via NaBH4 with full reduction achieved within 30 s. Moreover, as prepared nanocatalyst possesses excellent stability and recyclability with easy magnetic separation.