The modification of catalytic activity through the use of metallic promoters is a key strategy for optimizing performance, as electronic factors play a crucial role in regulating catalytic behavior. This study explores the electronic factors behind the adsorption of glycerol (Gly) on bimetallic nickel-based compounds (${\mathrm{Ni}}_3\mathrm{X}$) using density functional theory (DFT) calculations; incorporating Mn, Fe, Co, Cu, and Zn as promoters effectively tunes the d-band center of these systems, directly influencing their magnetic, adsorption, and catalytic properties. A good correlation between the calculated glycerol adsorption energy and the d-band filling of the studied bimetallic surfaces was identified. Interestingly, this correlation can be rationalized using the celebrated Newns–Anderson model based on the calculated d-band fillings and centers of the systems under study. Additionally, the adsorption energies and relative stability of other electro-oxidation intermediates toward dihydroxyacetone (DHA) were calculated. Notably, the ${\mathrm{Ni}}_3\mathrm{Co}$ and ${\mathrm{Ni}}_3\mathrm{Cu}$ systems exhibit an optimal balance between glycerol adsorption and DHA desorption, making them promising candidates for glycerol electro-oxidation. These theoretical insights address fundamental aspects of developing glycerol valorization processes and advancing alcohol electro-oxidation technologies in fuel cells with noble-metal-free catalysts.

Zn–air batteries (ZABs) are a promising technology; however, their commercialization is limited by challenges, including those occurring in the electrolyte, and thus, gel polymer electrolytes (GPEs) and hydrogels have emerged as substitutes for traditional aqueous electrolytes. In this work, PVA/PAA membranes were synthesized by the solvent casting method and soaked in 6 M KOH to act as GPEs. The thickness of the membrane was modified (50, 100, and 150 μm), and after determining the best thickness, the membrane was modified with synthesized SiO₂ nanospheres and multi-walled carbon nanotubes (CNTs). SEM micrographs revealed that the CNTs displayed lengths of tens of micrometers, having a narrow diameter (95 ± 7 nm). In addition, SEM revealed that the SiO₂ nanospheres had homogeneous shapes with sizes of 110 ± 10 nm. Physicochemical experiments revealed that SiO₂ incorporation at 5 wt.% increased the water uptake of the PVA/PAA membrane from 465% to 525% and the ionic conductivity to 170 mS cm⁻¹. The further addition of 0.5 wt.% CNTs did not impact the water uptake but it promoted a porous structure, increasing the power density and the stability, showing three-times-higher rechargeability than the ZAB operated with the PVA/PAA GPE.

Cathodic materials significantly influence the performance, durability, and sustainability of primary zinc‐air batteries (ZABs). This study focuses on the rational design of highly active metal‐free composites by tailoring the content of N and S heteroatoms in carbon nanotube‐graphene (CNTG) composites. The oxygen reduction reaction (ORR) tests showed onset potentials (E_o) of 0.88 V (N‐CNT) and 0.89 V (N‐graphene) for individual materials and 0.92 V for the N‐CNTG composite, highlighting the advantage of using a composite materialThe N content varied with dicyandiamide and urea, displaying changes in the surface area and N content (7.09 vs. 5.30 at. %), and in pyridinic and quaternary N species. The N content varied with dicyandiamide and urea, showing changes in the surface area and N content (7.09 vs. 5.30 at. %), and in pyridinic and quaternary N species. The abundance of pyridinic‐N species in N‐CNTG using urea enabled a higher ORR activity (E_o=0.92 V). The S incorporation through thiourea improved the E_o to 0.94 V (Pt/C=1.03 V). And, the combination of urea and thiourea resulted in a highly active and durable N,S‐CNTG material, displaying a E_o of 0.96 V, and an activity loss of 8.7 % (Pt/C=25.4 %) after 2000 cycles. In ZAB mode, this material displayed a voltage of 1.35 V, a power density of 107 mW cm⁻², and a specific capacity of 1060 mA h g⁻¹.