Nitrogen-doped WSe 2 few-layer nanotubes for electrocatalytic nitrate reduction via Se vacancies

N-doped WSe 2 few-layer nanotubes (NTs) were prepared and synchronously modulated by controlling the N content. Significant Se vacancies produced in N-WSe 2 NTs enhance the electrocatalytic activity of N-WSe 2 NTs for nitrate reduction reaction.