Enhancing Nitrogen Electroreduction to Ammonia by Doping Chlorine on Reduced Graphene Oxide

Abstract

As one of the possible alternatives to the Haber–Bosch process, electrochemical ammonia synthesis has been attracting considerable interest in recent years. However, most electrocatalysts are confronted with the predicament of a low yield rate for ammonia production. In this study, we report the chlorine-doped reduced graphene oxide that can efficiently electroreduce nitrogen to ammonia. At an applied potential of −0.3 V (vs RHE), the chlorine-doped reduced graphene oxide attains a high NH3 yield of 70.9 μg h–1 mgcat –1 (2.84 μg h–1 cm–2) with a Faraday efficiency (FE) of 5.97%, which shows a considerable ammonia yield in terms of the metal-free carbonaceous material electrocatalysts. Experimental results indicate that the chlorine doping can be propitious to remarkably strengthen the nitrogen adsorption in the defect structure. Density functional theory calculations verify this result and further reveal that the adsorbed nitrogen is reduced through the associative distal pathway. These results come down to the appropriate electronegativity of chlorine, which can induce the electron redistribution of the adjacent carbon atoms, favoring the electroreduction of N2. Our work expands a new member for the application of nonmetallic carbonaceous materials in nitrogen electroreduction.

A dog nose-inspired high-performance NH3 gas sensor of biomass carbon materials with a pleated structure derived from rose tea

“…The peak at 3428 cm À1 is associated with the stretching and bending vibrations of the O-H groups (hydroxyl and chemisorbed water). 24,25 The peaks at 2924 and 1736 cm À1 for the ORT are attributed to the stretching vibrations of C-H and C]O functional groups, respectively, 26,27 which are the characteristic groups of cellulose. The peaks at 1566 cm À1 for CRT are attributed to C]C vibrations and the peaks at 1028 cm À1 for ORT and CRT are attributed to C-O vibrations.…”

Atomically Structural Regulations of Carbon‐Based Single‐Atom Catalysts for Electrochemical CO2Reduction

“…As a result, the catalyst exhibited a high selective CO 2 ‐to‐CO conversion over 95% FE from −0.67 to −0.97 V. In addition to S, F atoms, the doping of B, P, Cl, and other heteroatoms have also been developed by researchers in energy‐related applications. [ 227,228 ] The key point of noncoordination heteroatom doping in carbon substrates for boosting CO 2 RR performance lies in the appropriate modulation of electron density over the M–N x sites, which can lower the activation energy barrier for critical steps in CO 2 RR reactions.…”

“…have also been developed by researchers in energy-related applications. [227,228] The key point of noncoordination heteroatom doping in carbon substrates for boosting CO 2 RR performance lies in the appropriate modulation of electron density over the M-N x sites, which can lower the activation energy barrier for critical steps in CO 2 RR reactions.…”

Multidimensional Nonstoichiometric Electrode Materials for Electrochemical Energy Conversion and Storage

“…The metal dopants cover almost all the metal elements, such as alkali metals, [45] alkaline-earth metals, [46,47] transition metals, [48][49][50][51][52] and noble metals, [53,54] while nonmetal dopants include boron, [55] carbon, [56] pnictogens, [57][58][59][60][61] chalcogens, [62] and halogens. [63,64] Depending on the doped materials, metal doping can be realized through solid-state, [50,65,66] co-precipitation, [67,68] hydro/solvothermal, [48,69] electrodeposition, [70,71] and sol-gel [72] methods. For example, by mixing Li 2 CO 3 , Na 2 CO 3 , and Mg(OH) 2 with MnO 2 precursor for high-temperature solid-phase sintering, Liu et al successfully synthesized Na/Mg co-doped LiMn 2 O 4 electrode material.…”