Multi-yolk–shell bismuth@porous carbon as a highly efficient electrocatalyst for artificial N2 fixation under ambient conditions

The conventional Haber–Bosch process dominates the production of industrial NH3, and unfortunately leads to a large amount of energy consumption and carbon dioxide emissions. Meanwhile, from the environmentally friendly and energy-saving point of view, electrocatalytic N2 fixation is gradually becoming a more promising and desirable alternative technique. Herein, multi-yolk–shell bismuth@porous carbon (MB@PC) composites were successfully synthesized via a facile simple hydrothermal reaction followed by a subsequent pyrolyzation. The as-prepared MB@PC composite can act as an efficient N2 reduction reaction (NRR) electrocatalyst under ambient conditions. Test results demonstrated that the MB@PC composite catalysts can deliver a high NH3 yield of 28.63 μg h−1 mg−1cat., a Faraday efficiency of 10.58% at −0.5 V versus a reversible hydrogen electrode, long-term electrochemical durability in N2-saturated 0.1 M HCl solution, and an excellent selectivity for NH3 formation, and are better than most reported bismuth-based electrocatalysts. The excellent NRR performance is mainly ascribed to the synergetic effect of good conductivity, the highly porous feature derived from the carbon framework and intrinsic electrocatalytic NRR activity of bismuth nanoparticles. Generally, the present research findings would provide an alternative avenue to produce other efficient non-precious metal electrocatalysts for clean energy applications.