Tailoring Electronic Structure of NbB2 Nanorods Through Selenium Incorporation for Synergistically Enhanced Hydrogen Evolution and Triboelectric Energy Harvesting.

The sluggish hydrogen evolution reaction (HER) kinetics of non-noble-metal catalysts remain a major challenge for efficient hydrogen production. Herein, selenium-doped niobium diboride (Se-NbB2) nanorods were synthesized via a molten-salt-assisted route followed by microwave-assisted treatment, yielding a catalyst with higher conductivity and superior electrocatalytic performance. HER activity reveals that Se-NbB2 exhibits excellent performance, requiring an overpotential of only 147 mV to achieve 10 mA cm- 2 and maintaining stable operation for more than 6 days under alkaline conditions. Furthermore, the catalyst demonstrates efficient bifunctional water-splitting performance, delivering 10 mA cm- 2 at a cell voltage of 1.79 V. First-principles calculations reveal that Se incorporation modulates the electronic structure of NbB2 by shifting the Nb d-band center upward and improving electrical conductivity, thereby optimizing hydrogen adsorption free energy toward thermoneutral conditions and accelerating HER kinetics. Beyond electrocatalysis, Se-NbB2 was employed as an electrode material in a triboelectric nanogenerator (TENG), generating a maximum output voltage of 703 V and a current of 33 µA. The enhanced catalytic and triboelectric performances are attributed to improved conductivity and charge-transport characteristics induced by selenium incorporation. This work highlights heteroatom-mediated electronic-structure engineering as an effective strategy for developing multifunctional transition-metal boride materials for sustainable energy conversion, hydrogen generation, and energy-harvesting technologies.