Sulphur Assisted Nitrogen-Rich CNF for Improving Electronic Interactions in Co-NiO Heterostructures Toward Accelerated Overall Water Splitting

Electrochemical water splitting is the eco-friendly route to generate green hydrogen, which is recognized as sustainable energy for the future. However, the cost, operational efficiency, and long-term durability of the electrochemical water splitting rely on the choice of the electrocatalysts. Hence, developing a superior design strategy is an important criterion to establish an efficient and sustainable water splitting system. Herein, a sulphur-rich Co-NiO heterostructure encapsulated on N-rich carbon nanofibers (SCNO@N-CNF) synthesized via a simple and efficient electrospinning technique is reported. The three-way redox active centers, viz., the electron redistributed active Co-delta (-)-NiO delta (+) interfaces, S-dopant sites with modified electronic density, and the porous N-CNF matrix, makes the prepared electrocatalyst more efficient toward oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The SCNO@N-CNF electrocatalyst exhibits a low OER and HER overpotentials (eta(OER) = 247 mV; eta(HER) = 169 mV) at a current density of 10 mA cm(-2). Moreover, SCNO@N-CNF was analyzed as the bifunctional electrocatalyst in overall electrochemical water splitting, and it is found to deliver 10 mA cm(-2) at only 1.58 V. Thus, the design and engineering of multiple active elements in a single electrocatalyst is anticipated as an effective approach to establish an efficient and sustainable water splitting system.

Automated summary

This paper reports on the synthesis of SCNO@N-CNF electrocatalyst via a simple and efficient electrospinning technique. The electrocatalyst exhibits multiple redox active centers, making it more efficient in oxygen evolution reaction and hydrogen evolution reaction. As a bifunctional electrocatalyst in overall electrochemical water splitting, SCNO@N-CNF delivers high current density at a low voltage.