Manipulation of Mott-Schottky Ni/CeO2 Heterojunctions into N-Doped Carbon Nanofibers for High-Efficiency Electrochemical Water Splitting.

Designing affordable and efficient bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has remained a long-lasting target for the progressing hydrogen economy. Utilization of metal/semiconductor interface effect has been lately established as a viable implementation to realize the favorable electrocatalytic performance due to the built-in electric field. Herein, a typical Mott-Schottky electrocatalyst by immobilizing Ni/CeO2 hetero-nanoparticles onto N-doped carbon nanofibers (abbreviated as Ni/CeO2 @N-CNFs hereafter) has been developed via a feasible electrospinning-carbonization tactic. Experimental findings and theoretic calculations substantiate that the elaborated constructed Ni/CeO2 heterojunction effectively triggers the self-driven charge transfer on heterointerfaces, leading to the promoted charge transfer rate, the optimized chemisorption energies for reaction intermediates and ultimately the expedited reaction kinetics. Therefore, the well-designed Ni/CeO2 @N-CNFs deliver superior HER and OER catalytic activities with overpotentials of 100 and 230 mV at 10 mA cm-2 , respectively, in alkaline solution. Furthermore, the Ni/CeO2 @N-CNFs-equipped electrolyzer also exhibits a low cell voltage of 1.56 V to attain 10 mA cm-2 and impressive long-term durability over 55 h. The innovative manipulation of electronic modulation via Mott-Schottky establishment may inspire the future development of economical electrocatalysts for diverse sustainable energy systems.