Adalder Ashadul, Paul Sourav, Ghorai Biswajit, Kapse Samadhan, Thapa Ranjit, Nagendra Abharana, Ghorai Uttam Kumar
Department of Industrial Chemistry & Applied Chemistry, Swami Vivekananda Research Centre, Ramakrishna Mission Vidyamandira, Belur Math, Howrah 711202, India.
Department of Physics, SRM University─AP, Amaravati, Andhra Pradesh 522240, India.
ACS Appl Mater Interfaces. 2023 Jul 26;15(29):34642-34650. doi: 10.1021/acsami.3c01847. Epub 2023 Jul 14.
Ammonia is produced through the energy-intensive Haber-Bosch process, which undergoes catalytic oxidation for the production of commercial nitric acid by the senescent Ostwald process. The two energy-intensive industrial processes demand for process sustainability. Hence, single-step electrocatalysis offers a promising approach toward a more environmentally friendly solution. Herein, we report a 10-electron pathway associated one-step electrochemical dinitrogen oxidation reaction (NOR) to nitric acid by manganese phthalocyanine (MnPc) hollow nano-structures under ambient conditions. The catalyst delivers a nitric acid yield of 513.2 μmol h g with 33.9% Faradaic efficiency @ 2.1 V versus reversible hydrogen electrode. The excellent NOR performances are achieved due to the specific-selectivity, presence of greater number of exposed active sites, recyclability, and long period stability. The extended X-ray absorption fine structure confirms that Mn atoms are coordinated to the pyrrolic and pyridinic nitrogen via Mn-N coordination. Density functional theory-based theoretical calculations confirm that the Mn-N site of MnPc is the main active center for NOR, which suppresses the oxygen evolution reaction. This work provides a new arena about the successful example of one step nitric acid production utilizing a Mn-N active site-based metal phthalocyanine electrocatalyst by dinitrogen oxidation for the development of a carbon-neutral sustainable society.
氨是通过能源密集型的哈伯-博施法生产的，该方法通过衰老的奥斯特瓦尔德法进行催化氧化以生产商业硝酸。这两个能源密集型工业过程对过程可持续性有要求。因此，单步电催化为更环保的解决方案提供了一种有前景的方法。在此，我们报道了在环境条件下，锰酞菁（MnPc）中空纳米结构通过10电子途径进行的一步电化学二氮氧化反应（NOR）生成硝酸。该催化剂在相对于可逆氢电极2.1 V的电压下，硝酸产率为513.2 μmol h g，法拉第效率为33.9%。由于特定选择性、大量暴露的活性位点的存在、可回收性和长期稳定性，实现了优异的NOR性能。扩展X射线吸收精细结构证实，Mn原子通过Mn-N配位与吡咯氮和吡啶氮配位。基于密度泛函理论的理论计算证实，MnPc的Mn-N位点是NOR的主要活性中心，它抑制析氧反应。这项工作为利用基于Mn-N活性位点的金属酞菁电催化剂通过二氮氧化一步生产硝酸的成功实例提供了一个新领域，以促进碳中性可持续社会的发展。
