Layered Nanocomposites of Polymer-Functionalized Reduced Graphene Oxide and Borocarbonitride with MoS₂ and MoSe₂ and Their Hydrogen Evolution Reaction Activity

Two dimensional heterostructure have been widely investigated for various applications in electrochemistry such as water splitting and battery storage. These heterostructures are mainly formed due to vander waals interaction, covalent cross-linking and electrostatic interactions. Herein, we have prepared nanocomposite of positively charged poly (diallyldimethylammonium chloride) (PDDA, shown as P)-functionalized reduced graphene oxide (RGO) and borocarbonitride (BC 6 N, shown as BCN for simplicity) sheets with layers of negatively charged MoS 2 and MoSe 2 by electrostatic interaction in solution phase. The nanocomposites exhibit superior photocatalytic hydrogen evolution reaction (HER) activity compared to the individual components, and the value increases with the MoS 2 /MoSe 2 content. The highest photocatalytic HER activity obtained is 11230 μmol h –1 g –1 in the nanocomposite P.RGO-MoS 2 , with a P.RGO-MoS 2 ratio of 1:5. The P.RGO-MoSe 2 (1:5) and P.BCN-MoS 2 (1:5) nanocomposites exhibit somewhat lower activities of 9540 and 8593 μmol h –1 g –1 , respectively. Prompted by literature reports that carbon-rich BCNs are efficient HER electrocatalysts, we have examined the electrocatalytic HER activity of P.BCN-MoS 2 (1:1, 1:5, and 1:7) nanocomposites. The electrocatalytic HER activity of P.BCN-MoS 2 (1:5) is found to be extraordinary, with an onset potential of −50 mV (vs RHE), comparable to that of platinum. References: - Geim, A. K. & Grigorieva, I. V. Van der Waals heterostructures. Nature 2013 499:7459 499 , 419–425 (2013). Pramoda, K., Gupta, U., Ahmad, I., Kumar, R. & Rao, C. N. R. Assemblies of covalently cross-linked nanosheets of MoS2 and of MoS2–RGO: synthesis and novel properties. J Mater Chem A Mater 4 , 8989–8994 (2016). Pramoda, K., Servottam, S., Kaur, M. & Rao, C. N. R. Layered Nanocomposites of Polymer-Functionalized Reduced Graphene Oxide and Borocarbonitride with MoS2 and MoSe2 and Their Hydrogen Evolution Reaction Activity. ACS Appl Nano Mater 3 , 1792–1799 (2020). Figure 1