Synthesis of sulfur-encapsulated mullite structure Bi0/Fe0-Rich Bi2Fe4O9-x framework by advanced probe sonic approach applied for augmented electroactive hydrogen production, storage and photoactive degradation studies

A new series of dual Bi0/Fe0-rich in sulfur -encapsulated BFNPs (SBFNPs-framework) with a sulfur content ranging from 1.0% to 3.0% were prepared using an advanced probe -sonic approach. The SBFNPs-framework with a sulfur content of 2.0% exhibited a maximum methylene -blue (MB) photo -degradability of 84.20% at 120 min of visible -light exposure. The MB degradation rate of the SBFNPs-framework (0.00839 min -1) was faster than that of pure-BFNPs (0.00308 min -1). Furthermore, the electro-catalyst of SBFNPs-framework demonstrated remarkable hydrogen -production activity, as indicated by a low over -potential (204 mV), a small Tafel-slope (69 mV/dec), a higher double -layer -capacitance (142.0 mF/cm2), a larger electro-chemically-active-surface-area (40.6 cm2), a plentiful presence of catalytic -active -sites (5.65 x10-7 mol/cm2), and excellent stability, respectively. Also, the hydrogen -storage capacity of the SBFNPs-framework exhibited a maximum discharge capacity of 717.35 mAhg- 1 and a hydrogen -storage capacity of 2.66 wt% at a 2.0% sulfur content. These findings have great potential implications for future energy storage and environmental applications.