Nanoporous boron-doped diamond-like carbon (DLC) electrodes for electrocatalytic nitrate reduction

Abstract

The electrocatalytic nitrate reduction reaction (NO₃RR) is regarded as a promising strategy to rebalance the global nitrogen cycle. However, the multi-step electron and proton transfer involved in NO₃RR severely compromises its faradaic efficiency; thus, efficient electrocatalysts for NO₃RR are desired to accelerate this process. Herein, we applied the “laser direct-writing” method to fabricate a nanoporous boron-doped DLC electrode for efficient electrocatalytic NO₃RR, and we optimized catalytic activity by modulating the boron doping concentration in the DLC catalyst. It is noted that the electrode achieved a high faradaic efficiency of 80% and an ammonia yield rate of 550 µg cm⁻² h⁻¹ at −0.59 V vs. RHE. In situ Raman spectroscopy combined with X-ray photoelectron spectroscopy (XPS) and multiple characterization techniques indicated that B_0.57DG effectively promoted the reduction of intermediate species. Strong reducing *H species can accelerate hydrogenation during nitrate electroreduction, thereby enhancing the efficiency of ammonia synthesis.