Two-dimensional titanium MXene-neodymium molybdate/tungstate/vanadate composites as efficient bifunctional catalysts for environmental remediation and hydrogen evolution reaction

In this work, we report a comparative study of lanthanide-based neodymium rare-earth metal composites with oxyanions of molybdenum, tungsten, and vanadium, specifically Nd2Mo3O12 (NdMo), Nd2(WO4)3 (NdW), and NdVO4 (NdV). A simple precipitation method was adopted to synthesize neodymium-based compounds, while two-dimensional titanium carbide MXene (TMX) was prepared via acid etching. The integration of TMX with neodymium compounds was synthesized via impregnation, forming a TMX–Nd-based oxyanion composite. The structural, optical, and morphological properties of the synthesized materials were systematically characterized with various physicochemical techniques. The composites were assessed for two key environmental applications: photocatalytic organic pollutants degradation and electrochemical hydrogen evolution. Among the series, TMX–NdMo exhibited superior photocatalytic efficiency, achieving higher degradation rates for ampicillin (91.4%) and TCH (88.9%) under solar irradiation within 80 and 120 min, respectively. The possible reaction pathway predicted by LC–MS and the efficiency of the TMX–NdMo were examined for real-time wastewater. Additionally, the TMX–NdMo composite achieved a low overpotential of 182 mV and a Tafel slope of 129 mV/dec at 10 mA/cm2, indicating efficient hydrogen evolution reaction activity. The augmented performance is ascribed to efficient interfacial interactions, an increase in surface area, and improved charge separation offered by the TMX framework. These results highlight their potential for use in hybrid and sustainable nanomaterial applications.