Nb2O5–Ni3N heterojunction tuned by interface oxygen vacancy engineering for the enhancement of electrocatalytic hydrogen evolution activity

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 9; no. 19; pp. 11563 - 11570
• Main Authors: Xiao Hui Chen, Xiao Lin Li, Li Li Wu, Fu, Hong Chuan, Luo, Juan, Shen, Li, Zhang, Qing, Jing Lei Lei, Luo, Hong Qun, Li, Nian Bing
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 21.05.2021
• Subjects: Adsorbed water; Adsorption; Catalysts; Catalytic activity; Coordination numbers; Density functional theory; Electrocatalysts; energy; Free energy; Gibbs free energy; Heterojunctions; Hydrogen; Hydrogen evolution reactions; hydrogen production; Nickel; Niobium oxides; Oxygen; synergism; Synergistic effect; Vacancies
• ISSN: 2050-7488; 2050-7496; 2050-7496
• DOI: 10.1039/d1ta01872h

The requirement of hydrogen adsorption Gibbs free energy (ΔGH*) approximating to 0 eV limits the hydrogen evolution reaction (HER) activity of most electrocatalysts in alkaline media. The construction of interface and defects engineering is an effective strategy to obtain the optimal ΔGH*. Ni3N exhibits poor HER activity due to its undesirable ΔGH*. By cooperating with Nb2O5, the d-band center of Ni3N was reduced, improving its catalytic performance. The optimized Nb2O5–Ni3N displays an overpotential of 80 mV at 10 mA cm−2 and superior activity than the benchmark Pt/C catalyst when the current density is greater than 125 mA cm−2. Experimental and density functional theory results demonstrate that the improved catalytic activity is because the electronic interaction between Ni and Nb changes the coordination numbers of these two atoms, resulting in oxygen vacancies at the interface. Under the synergistic effect of Nb2O5 and Ni3N, the catalyst exhibits optimal ΔGH* and water adsorption energy.