High Performance Cobalt-Vanadium Layered Double Hydroxide Nanosheets for Photoelectrochemical Reduction of Nitrogen

Photoelectrochemical (PEC) nitrogen reduction to ammonia under ambient conditions is an efficient and environmentally friendly alternative to the traditional Haber-Bosch process. However, ambient nitrogen reduction reaction (NRR) still faces numerous challenges like high reaction barrier, onset of competitive hydrogen evolution reaction at low potential, low ammonia yields, and poor selectivities. Herein, for the first time, we take advantage of the nanosheet structure of layered double hydroxide (LDH) materials to develop CoV-LDH nanosheet arrays as PEC NRR catalytic materials. By tuning the Co/V ratio, the optimized Co2V1-LDH nanosheet material is capable to accelerate the N equivalent to N bond cleavage, providing a large number of exposed active sites, and improving the catalytic activity. The developed Co2V1-LDH photocathode attained a high NH3 yield rate (8.97x10(-7) mol h(-1) cm(-2)) and high Faradaic efficiency (52.4 %) at -0.2 V vs. RHE. Notably, Co2V1-LDH exhibits excellent durability over five consecutive reaction cycles. Therefore, this work provides a basis to further design and explore the efficient materials for ambient photoelectrocatalytic nitrogen fixation.