Wei Wang,Jing-Zhe Li,Shi-Jian Luo,Zi-Xuan Yao,Kuan-Guan Liu
Using the atomic precisely structurally characterized clusters as electrocatalysts can provide some possible structure information about the active intermediate during the electrocatalytic N 2 reduction reaction (NRR) process. A Cu4 cluster, named [(bpy) 4 Cu 4 (C 10 H 8 SO 3 ) 4 (OH) 4 ]•4H 2 O ( 1 ), has been synthesized and fully characterized by IR, SXRD, XPS, EPR, et al. Single crystal structural analysis reveals that the core structure of the cluster has a step-scheme conformation with two μ 2 -OH and two μ 3 -OH groups. Electro-catalysis studies of this cluster show that it can achieve a highest NH 3 yield of 2.18 μg h −1 mg −1 and a FE of 0.97 % at −0.6 V. The excellent NRR performance may be attributable to the additional μ 3 -OH groups, based on the contrastively study of the other electrocatalysts of the Cu powder and the Cu 2 complex, named [(μ 2 -OH)(μ 2 -Cl)(bpy) 2 Cu 2 Cl 2 ] ( 2 ), with one μ 2 -OH group in its structure. This work provides some structure information about the possible active sites during the NRR process and inspires us to develop new cluster as efficient electrocatalysts for advancing sustainable NH 3 production. Using the atomic precisely structurally characterized clusters as electrocatalysts can provide some possible structure information about the active intermediate during the electrocatalytic N 2 reduction reaction (NRR) process. A Cu4 cluster, named [(bpy) 4 Cu 4 (C 10 H 8 SO 3 ) 4 (OH) 4 ]•4H 2 O ( 1 ), has been synthesized and fully characterized by IR, SXRD, XPS, EPR, et al. Single crystal structural analysis reveals that the core structure of the cluster has a step-scheme conformation with two μ 2 -OH and two μ 3 -OH groups. Electro-catalysis studies of this cluster show that it can achieve a highest NH 3 yield of 2.18 μg h −1 mg −1 and a FE of 0.97 % at −0.6 V. The excellent NRR performance may be attributable to the additional μ 3 -OH groups, based on the contrastively study of the other electrocatalysts of the Cu powder and the Cu 2 complex, named [(μ 2 -OH)(μ 2 -Cl)(bpy) 2 Cu 2 Cl 2 ] ( 2 ), with one μ 2 -OH group in its structure. This work provides some structure information about the possible active sites during the NRR process and inspires us to develop new cluster as efficient electrocatalysts for advancing sustainable NH 3 production.
Shijian Luo,Xiaoman Li,Wanguo Gao,Haiqiang Zhang,Min Luo
Today, industrial ammonia synthesis mainly depends on the Haber–Bosch process, which causes a lot of energy consumption and huge CO2 emissions. The electrochemical N2 reduction reaction (NRR) is considered a more sustainable and environmentally benign alternative to produce ammonia, but it requires an efficient catalyst to overcome the difficulty of N2 activation. In this work, we reported that MOF-derived C@NiO@Ni microtubes behaved as a high-efficiency electrocatalyst in 0.1 M KOH electrolyte. This electrocatalyst achieved a high NH3 yield of 43.15 μg h−1 mgcat.−1 and faradaic efficiency of 10.9% at −0.7 V vs. a reversible hydrogen electrode. The experimental results indicated that the excellent NRR performance originated from the oxygen vacancies in NiO. Moreover, the abundant NiO/Ni interfaces were conducive to proton adsorption and further enhanced the NRR performance.
Current artificial NH3 synthesis relies heavily on the Haber–Bosch process that involves enormous energy consumption and huge CO2 emission. The electrochemical N2 reduction reaction (NRR) offers an eco-friendly and sustainable alternative but demands cost-effective and efficient NRR electrocatalysts. Herein, NiO nanodots (∼2 nm) supported on graphene (NiO/G) were developed as a high-performance NRR electrocatalyst at ambient conditions. Electrochemical tests indicated that the NiO/G exhibited a high NH3 yield (18.6 μg h–1 mg–1) and Faradaic efficiency (7.8%) at −0.7 V vs reversible hydrogen electrode, outperforming the most reported NRR electrocatalysts. Experimental and density functional theory (DFT) results revealed that NiO was the dominating active center, and nanodot structure enabled the NiO to expose more active sites. DFT results further demonstrated that the distal associative route was the preferable NRR pathway with *N2 → *NNH being the rate-determining step.