Construction of controllable hydrogen production system of aluminum-based gel via solvent exchange strategy and its...

High-activity aluminum-based composites for hydrogen production have uncontrollable reaction kinetics, releasing large amounts of hydrogen and heat in a short period of time, which severely hinders their application in proton exchange membrane fuel cells (PEMFCs). This study reports a novel method for embedding highly active Al-based composites into PVA/DMSO organogels, where polyvinyl alcohol (PVA) serves as the gel factor and dimethyl sulfoxide (DMSO) acts as the dispersing medium. This method is based on a solvent exchange strategy, which regulates the gradient diffusion of DMSO and H₂O by adjusting the material network structure, thereby controlling the kinetics of the aluminum-water reaction. Within the gel, the three-dimensional network structure effectively disperses the active aluminum components, preventing agglomeration from affecting the hydrogen production performance of the material. At the same time, DMSO physically encapsulates the aluminum particles, further enhancing the material's antioxidant capacity. In this paper, the factors affecting the hydrogen production performance of Al-based gels were investigated. Typically, the Al-based gels can precisely modulate stable hydrogen generation rates from 4.2 to 52.4 mL·s^-1 while maintaining a final conversion efficiency of about 90 % by adjusting the concentration of PVA and the ratio of Al-based composite to PVA solution. Additionally, after further optimizing these material parameters, the Al-based gel achieved a stable discharge of 5.2 W PEMFC. The Al-based gel's pore size, active aluminum content per unit area, and structural stability are the key elements influencing hydrogen production, as validated by SEM, BET, and other characterization techniques.