Metal–Organic Framework (MOF)-Derived Mn2O3@C for Sustainable Hydrogen Generation and Antibacterial Efficacy Against Human Pathogenic Bacteria

Hydrogen gas has been regarded as one of the most promising energy sources. Hydrolysis of hydrides is one of the methods for producing hydrogen that has been documented. However, efficient catalysts are necessary to increase the rate at which hydrogen is generated. In the current investigation, Mn₂O₃@C derived from metal–organic framework (MOF) was used, for the first time, as an efficient catalyst for the green generation of H₂—a clean and sustainable fuel—from the hydrolysis of NaBH₄. In addition, the biological performances of this nanocatalyst towards six types of human pathogenic bacteria were also tested. Mn₂O₃@C was fabricated from the carbonization of manganese(II) benzene-dicarboxylate metal–organic frameworks (Mn-BDC). The fabricated catalyst was characterized by XRD, XPS, FTIR, HRTEM, and nitrogen sorption analyses. XRD and XPS analyses confirmed the successful formation of Mn₂O₃@C at a calcination temperature of 400 °C. Results revealed that, at a reaction temperature of 28 °C, Mn₂O₃@C offers values of hydrogen generation rate (HGR) of 150, 352, 555, 885, and 1250 mL min⁻¹ g⁻¹ corresponding to weight of NaBH₄ of 0.19, 0.3, 0.5, 0.7, and 1.0 g, respectively. Furthermore, the catalytic performance is significantly influenced by the reaction temperature; where at 28, 35, 40, and 50 °C, respectively, HGR values of 885, 1150, 1667, and 2857 mL min⁻¹ g⁻¹ were achieved. According to the pseudo-first-order equation, Mn₂O₃@C has an estimated apparent activation energy of 41.5 kJ mol⁻¹. Moreover, thermodynamic calculations showed that borohydride hydrolyzes over Mn₂O₃@C in an endothermic, entropy-driven, and spontaneous manner. The antibacterial properties of Mn₂O₃@C NPs were tested against six pathogenic bacteria: Escherichia coli, Klebsiella pneumoniae, Serratia plymuthica, Bacillus cereus, B. subtilis, and Staphylococcus aureus. Mn₂O₃@C NPs showed high antibacterial properties, especially at 150 μg mL⁻¹ concentration, with growth inhibition of 82.3%, 73.8%, 72.7%, and 71.8% of S. aureus, E. coli, B. subtilis, and B. cereus, compared with 67%, 58.2%, 56.6%, and 61.4% of chloramphenicol, respectively.