Lanthanide Oxides in Ammonia Synthesis Catalysts: A Comprehensive Review

Abstract

The production of ammonia through the Haber–Bosch process is a large-scale catalytic industrial endeavour with substantial energy consumption. A key area of energy optimisation for this process involves efforts to ease the synthesis reaction conditions, particularly by reducing the operating pressure. To achieve this goal, new catalysts are designed to function effectively at lower pressures and temperatures. In recent years, reports in the literature concerning including lanthanide oxides in the catalysts’ composition have started appearing more frequently. This review article offers a concise overview of the pivotal role that lanthanide oxides play in the field of ammonia synthesis catalysts. The paper delves into the diverse utilisation of lanthanide oxides, emphasising their role in catalytic systems. The review explores recent advances in the design of catalysts incorporating lanthanide oxides as promoters or support materials, highlighting their impact on enhancing catalyst stability, activity, and operation. Three main groups of catalysts are discussed, where iron, ruthenium, and cobalt constitute the active phase. Insights from recent research efforts are synthesised to provide a comprehensive perspective on the application prospects of lanthanide oxides in ammonia synthesis catalysts.