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Ammonia (NH3) production is of global concern for today's food supply security and as future energy vector. Plasma technology can add to supply‐chain resilience of fertilizer production and improve the environmental profile using renewable energy; allowing distributed NH3 production. With the objective to provide process intensification of small‐capacity reactors for local supply, a novel micropyramid‐disk plasma reactor operated in micro‐arc mode was developed. NH3 was synthesized from N2, nitrogen, and H2, hydrogen over Ru/MCM‐41 catalyst at atmospheric pressure. The microplasma brings plasma and catalyst surface close together and intensifies the electric field. The arc plasma elevates temperature, 'nonthermal', releasing high‐energy free electrons, known to be effective in converting low‐reactive molecules. The study demonstrates that microplasma, with reduced electrode‐to‐electrode dimensions and a microstructured reaction environment, enhances the performance of the NH3 synthesis and opens novel process windows. This is detailed on the impact of feed ratio (N2/H2), applied voltage, frequency, electrode gap, and the flow distribution by which the gas is fed in. Optical emission spectroscopy (OES) was used to identify vibrationally and other excited species generated by the microplasma and confirms the catalyst is in symbiosis with the radicals. [ABSTRACT FROM AUTHOR]

Plasma-assisted ammonia (NH 3) synthesis is receiving significant attention·NH 3 is globally important to fertilizer production and as a fuel. However, plasma research is, intrinsically, significantly cross-disciplinary and encompasses chemistry, physics, materials science and electrical engineering. A consequence is that it is uncommon for plasma researchers to be fully aware of the entirety of plasma-related research beyond a particular discipline. Here for the first time we critically review this cross-disciplinary literature to address this problem using plasma-enabled NH 3 synthesis as an eminent showcase for process chemistry. A justification is that an improved understanding will be helpful to deal with the complexity of plasma processes which typically involve a set of chemical reactions with an ensemble of many short-lived excited, or reactive, species that vary amongst different plasmas. In this way, mechanisms for plasma-driven NH 3 synthesis are deciphered which helps to improve plasma reaction engineering. Modern analytical techniques are critical in deciphering these fundamentals and in this review optical emission spectroscopy (OES) is featured. [ABSTRACT FROM AUTHOR]