Across the Board: Federico Bella on Electrochemical Nitrogen Reduction

Abstract

In this series of articles, the board members of ChemSusChem discussrecent research articles that they consider of exceptional quality and importance for sustainability.T his entry features Prof. F. Bella, who discusses the electrochemical reduction of nitrogen to produce ammonia through the addition of protons and electrons under mild conditions (25 8C, 1atm). This reaction has the potential to replace the energy-intensive traditional Haber-Bosch process but faces severalc hallenges and pitfalls.To day,t he fortune of 8billion people living in this world is closely dependento ns ome essential factors, among whichf ertilizers surely play ak ey role. The scientific communityi nt he field of chemical sciences fully shares the idea that the Haber-Bosch process for the synthesis of ammonia at al arge scale allowed the demographic boom of the twentieth century,o wing to the possibility of fertilizing the land and feeding people. In parallel, the use of ammonia as an intermediate for the industrial chemistry,a saproduct for domestic use, and as ac omponent for variousp rocesses behind the production of plastics furtherh ighlighted the strategic role of Haber-Bosch plants at ag lobal scale. [1] We should take into account that 170 million tons of ammonia are produced per year and that, even if ah undred years of development have led to an overall decrease in energy consumption and production cost, the Haber-Bosch process is responsible for approximately 2% of the current global energy consumption. Considering the high temperature and pressure conditions of this process, along with the requirement of clean hydrogen and nitrogen reactantg ases, it should also be kept in mind that ammonia industrial synthesis is responsible for 1.44 %o fg lobal CO 2 emissions (2.86 tons of CO 2 per ton of NH 3 in average). As at hird critical point, Haber-Bosch plants requireb illions of euros of capital to be built through an engineering project that takes several years to complete. [2] The scientific community hasr ecently come back to an old "Holy Grail" concept:t rying to perform ammonia synthesis under mild conditions and without the huge constrains of the Haber-Bosch large-scale (geo-localized) plants. Thisc hallenge is extremelyd ifficult because the aim is to completely eliminate carbonemissions and deliver both hydrogen and required powerf rom renewable sources. [3] This hot topic in the scientific literature( 2018-today) has been approached throughd ifferent researchs trategies:b iochemical, photocatalytic, chemical looping, plasma-chemical,and electrochemical.Electrochemistry is today al eadingd iscipline within applied chemicals ciences, and the strategies developed in the last ten years in the fields of CO 2 conversion,H 2 technologies, and solar energy conversion/storage devices seem usefult op ave the way to resolve the electrochemical nitrogen reduction reaction (E-NRR) challenge. The advantage of the electrochemical route lies in the thermodynamic force,w hich allows af lexible control of electrochemical potentials,t hus r...

WOx nanoparticles coupled with nitrogen-doped porous carbon toward electrocatalytic N2 reduction

“…1,15,16 Designing and preparing high-performance catalysts to break NuN bonds, inhibit competitive reactions, and effectively reduce N 2 to NH 3 are always the main goals of eNRR. 17,18 Traditionally, high-performance eNRR catalysts are mostly based on noble metals (Pt, Pd, Au, Ru, etc.). 7,8,19 Nevertheless, the scarcity and higher costs seriously limit the large-scale application of noble metal-based catalysts.…”