Deng Dan, Yang Li-Ming
Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, Hubei Engineering Research Center for Biomaterials and Medical Protective Materials, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
ACS Appl Mater Interfaces. 2023 May 10;15(18):22012-22024. doi: 10.1021/acsami.3c00004. Epub 2023 Apr 25.
Electrocatalytic reduction of nitrogen to ammonia (eNRR) under ambient condition is a potential sustainable and promising alternative to the traditional Haber-Bosch process. However, this electrochemical transformation is limited by the high overpotential, poor selectivity, low efficiency, and low yield. Herein, a new class of two-dimensional (2D) organometallic nanosheets c-TM-TCNE (c = cross motif, TM = 3d/4d/5d transition metals, TCNE = tetracyanoethylene) were comprehensively investigated as potential electrocatalysts for eNRR through high-throughput screening combined with spin-polarized density functional theory computations. After a multistep screening and follow-up systematic evaluation, c-Mo-TCNE and c-Nb-TCNE were selected as eligible catalysts, and c-Mo-TCNE showed the lowest limiting potential of -0.35 V via a distal pathway, displaying high catalytic performance. In addition, the desorption of NH from the surface of c-Mo-TCNE catalyst is also easy, with the free energy being 0.34 eV. Furthermore, the stability, metallicity, and eNRR selectivity are preeminent, making c-Mo-TCNE a promising catalyst. Unexpectedly, the magnetic moment of the transition metal shows a strong correlation with the catalytic activity (limiting potential), i.e., the larger the magnetic moment of the transition metal, the smaller the limiting potential of the electrocatalyst. The Mo atom has the largest magnetic moment and the c-Mo-TCNE catalyst features the smallest magnitude of limiting potential. Thus, the magnetic moment can be used as an effective descriptor for eNRR on c-TM-TCNE catalysts. The present study opens a way toward the rational design of highly efficient electrocatalysts for eNRR with novel two-dimensional functional materials. This work will promote further experimental efforts in this field.
在环境条件下将氮气电催化还原为氨（eNRR）是传统哈伯-博施法潜在的可持续且有前景的替代方法。然而，这种电化学转化受到高过电位、低选择性、低效率和低产率的限制。在此，通过高通量筛选结合自旋极化密度泛函理论计算，对一类新型二维（2D）有机金属纳米片c-TM-TCNE（c = 交叉 motif，TM = 3d/4d/5d过渡金属，TCNE = 四氰基乙烯）作为eNRR潜在电催化剂进行了全面研究。经过多步筛选和后续系统评估，c-Mo-TCNE和c-Nb-TCNE被选为合格催化剂，c-Mo-TCNE通过远端途径显示出最低的极限电位-0.35 V，表现出高催化性能。此外，NH从c-Mo-TCNE催化剂表面的脱附也很容易，自由能为0.34 eV。此外，其稳定性、金属性和eNRR选择性都很突出，使c-Mo-TCNE成为一种有前景的催化剂。出乎意料的是，过渡金属的磁矩与催化活性（极限电位）呈现出很强的相关性，即过渡金属的磁矩越大，电催化剂的极限电位越小。Mo原子具有最大的磁矩，c-Mo-TCNE催化剂具有最小的极限电位值。因此，磁矩可作为c-TM-TCNE催化剂上eNRR的有效描述符。本研究为利用新型二维功能材料合理设计高效的eNRR电催化剂开辟了一条道路。这项工作将推动该领域进一步的实验研究。
