Ti3C2Tx MXene-enhanced Cu2S nanosheet composite for selective electrochemical conversion of waste crude glycerol to glyceric acid

In this work, we present a straightforward approach to synthesizing a highly active, sandwich-like composite electrocatalyst consisting of Cu₂S/crude glycerol-derived carbon/Ti₃C₂Tₓ MXene for glycerol electrooxidation (GEOR) and crude glycerol electrooxidation reaction (CGEOR). Cu₂S nanosheet arrays are grown directly on sulfur-doped crude glycerol-derived carbon (CGC) via a low-temperature co-reduction method, followed by the incorporation of MXene through a mechanochemical approach. The composite material’s physicochemical properties were comprehensively analyzed using SEM/EDX, TEM, XRD, and XPS. Electrochemical studies revealed that the Cu₂S/CGC/MX electrode exhibited exceptional catalytic activity, achieving a voltage of 0.46 V at 50 mA/cm² with a turnover frequency (TOF) of 13.1 s⁻¹, significantly outperforming Cu₂S (0.71 V), Cu₂S/CGC (0.58 V), and MXene (0.97 V), highlighting the synergistic effect of the composite structure. High-performance liquid chromatography (HPLC) analysis confirmed 100% glycerol conversion, with a remarkable 94% selectivity toward glyceric acid and a Faradaic efficiency of 60% for GEOR, while CGEOR achieved 80% selectivity. Density functional theory (DFT) analysis attributed the superior conversion efficiency to the MXene-enhanced catalytic surface. Post-electrolysis analysis via SEM/EDX and XPS confirmed controlled surface reconstruction due to sulfur leaching in the composite electrode compared to without MXene, highlighting the role of MXene in the Cu 2 S electrode. The integration of crude glycerol as both a carbon precursor and fuel offer a sustainable approach to waste valorization and alternative energy generation, demonstrating the potential for efficient, eco-friendly electrocatalysts in renewable energy applications. • A novel sandwich Cu₂S/CGC/MX composite achieved 100% GEOR conversion with 94% glyceric acid selectivity and 80% selectivity for CGEOR. • The composite demonstrated a low voltage of 0.46 V at 50 mA/cm², outperforming other materials tested. • MXene (MX) incorporation enhanced reaction kinetics and controlled sulfur leaching, improving catalyst stability. • DFT analysis confirmed that MXene’s surface was crucial to the exceptional catalytic performance. • Post-GEOR XPS and SEM/EDX analysis revealed minimal surface reconstruction, indicating MXene’s stabilizing role in Cu₂S. • CGEOR performance matched GEOR, proving effectiveness with crude glycerol impurities. • Direct crude glycerol utilization reduces costs and aligns with sustainable energy goals (SDG 7). • The catalyst enables selective glyceric acid production, valuable for pharmaceuticals and polymer synthesis.