Data for Figures: "Selective Hydrogen Evolution Reaction in HMF- containing mild alkaline electrolytes on structurally engineered MoS2@GNP cathode materials"

Overview This record contains the underlying raw data for the figures presented in the publication: "Selective Hydrogen Evolution Reaction in HMF-containing mild alkaline electrolytes on structurally engineered MoS2@GNP cathode materials". The study was conducted as part of the ELOBIO project (Grant No. 101070856) and investigates the use of noble-metal-free cathodes for selective Hydrogen Evolution Reaction (HER) in the presence of biomass-derived molecules. The research compares 2H-MoS₂ nanospheres (NSp) and nanosheets (NSh) supported on Graphene Nanoplatelets (GNPs), highlighting the critical role of microstructure engineering in achieving high activity and stability in mild alkaline conditions and in the presence of HMF. Data Content The provided files correspond to the following figures in the manuscript: Figure 1: XRD patterns for structural identification of MoS₂ Nanospheres and Nanosheets. Figure 4: Comparative Cyclic Voltammetry (CV) of MoS₂ NSp, NSh, and their respective GNP composites. Figure 5: CV stability and performance of MoS₂ NSh@GNPs at various HMF concentrations (10, 30, 50, 100 mM). Figure 6: Chronopotentiometry (CP) stability tests on Glassy Carbon (RD.GC) and Carbon Paper (CP) electrodes. Figure 7: ¹H NMR spectroscopy data for liquid product identification in different electrolyte conditions. Figure 8: Micro-gas Chromatography (µGC) analysis and Faraday Efficiency (FE) for H₂ and O₂ evolution during 1h chronoamperometry at -0.5 V vs RHE. Methodology Electrochemical measurements were performed at 25 °C using a Origalys Origalflex potentiostat. A standard three-electrode membrane-less cell was employed with: Working Electrode: MoS₂ nanostructures (NSp or NSh) with Graphene Nanoplatelets (GNPs) deposited on Glassy Carbon or Carbon Paper. Counter/Reference: A Glassy Carbon plate (CE) and a Hg/HgO (RE) were used. Electrolyte: 0.1 M NaOH + 1 M Na₂SO₄ (pH 13) with HMF concentrations ranging from 10 to 100 mM. Potentials were converted to the RHE scale. Structural and Product Analysis: XRD: Crystal phase identification of the 2H-MoS₂ was performed using a PANalytical X'Pert Pro diffractometer with Cu Kα radiation. ¹H NMR: Liquid-phase products were analyzed at the Universidad Politécnica de Madrid NMR facility to identify HMF derivatives. µGC: Real-time gas analysis (H₂, O₂) was performed via an Agilent 990 Micro GC to determine Faraday Efficiency (FE). Funding This work is part of the ELOBIO project. The project ELOBIO received funding from the European Union’s Horizon Europe EIC-2021-PATHFINDERCHALLENGES-01-04, under grant agreement number 101070856. Acknowledgments The authors acknowledge M. D. Molero Vilchez for technical assistance at the NMR facility.