Charge redistribution on NiCo-P hybrid nanoneedle via Br doping enables highly HER

Abstract

Designing and manufacturing a catalyst with promoted activity and robust stability plays a great role in hydrogen production through electrocatalytic water splitting, but it still remains a great challenge. Herein, this paper reports a porous Br doping NiCoP nanoneedles grown onto the coarsen nickel foam (NF/Ni@Br-NiCoP NNs) through a sequential process of electrodeposition, hydrothermal, and thermal phosphorization. The characterization demonstrates that Br enhanced the electric conductivity and regulated the electron structure, thus leading to a proper H absorption energy (ΔGH*) of –0.13 eV. As a sequence, the NF/Ni@Br-NiCoP NNs only needs 35 (170 mV) to reach 10 (100 mA cm−2) for HER. In addition, the NF/Ni@Br-NiCoP NNs exhibits long-term durability for HER, which the overpotential increased by approximately 3.84 % post 100 h at 50 mA cm−2. Additionally, the KSCN poisoning experiment and first-principle density function theory (DFT) calculation reveal that the Co served as the active site due to the most proper ΔGH*. Moreover, the in-situ Raman spectroscopies characterization indicates that the Ni(OH)2 and α-Co(OH)2 were generated in HER. Hence, this study not only demonstrates a facile synthesis route to prepare HER catalysts, but also establishes a detailed understanding of the interaction between crystal structure, morphology, and electrocatalytic activity.