Transforming electrochemical hydrogen Production: Tannic Acid-Boosted CoNi alloy integration with Multi-Walled carbon nanotubes for advanced bifunctional catalysis.

The dimensions of alloy nanoparticles or nanosheets have emerged as a critical determinant for their prowess as outstanding electrocatalysts in water decomposition. Remarkably, the reduction in nanoparticle size results in an expanded active specific surface area, elevating reaction kinetics and showcasing groundbreaking potential. In a significant leap towards innovation, we introduced tannic acid (TA) to modify multi-walled carbon nanotubes (MWCNTs) and CoNi alloys. This ingenious strategy not only finely tuned the size of CoNi alloys but also securely anchored them to the MWCNTs substrate. The resulting synergistic "carbon transportation network" accelerated electron transfer during the reaction, markedly enhancing efficiency. Furthermore, the exceptional synergy of Co and Ni elements establishes CoNi/MWCNTs as highly efficient electrocatalysts. Experimental findings unequivocally demonstrate that TA-CoNi/MWCNTs require minimal overpotentials of 171 and 294 mV to achieve a current density of ± 10 mA cm. Serving as both anode and cathode for overall water splitting, TA-CoNi/MWCNTs demand a low voltage of 1.66 V at 10 mA cm, maintaining structural integrity throughout extensive cyclic stability testing. These results propel TA-CoNi/MWCNTs as promising candidates for future electrocatalytic advancements.