A catalyst that makes hydrogen from ammonia can lose activity as its surface oxidizes or becomes blocked by nitrogen. A National University of Singapore team reports a catalyst design and a regeneration routine that addressed both problems, sustaining hydrogen production for more than 2,000 hours in laboratory tests. A higher-current test ran for 500 hours. Both tests were conducted at 80°C.
The work concerns electrochemical ammonia cracking, in which electricity drives the conversion of ammonia into nitrogen and hydrogen. Ammonia is easier to store and transport than hydrogen gas, the report explains, so producing hydrogen from it near where it is needed could ease some storage and transport challenges. The approach remains under development, however, and the reported tests do not establish how it would perform at larger scale.
The team was led by Professor Chen Wei of NUS’s Departments of Physics and Chemistry. The reported catalyst, called Pt/Fe-NC, consists of platinum nanoparticles on nitrogen-doped carbon, with iron atoms dispersed individually across the support. The report says the catalyst showed more than ten times the ammonia oxidation activity of a commercial platinum-on-carbon catalyst under the tested conditions. It also describes the material as effective for hydrogen production, allowing the same catalyst to be used for both key reactions in the process.
The report attributes the catalyst’s behavior to interactions between platinum and the iron-containing support. Electron transfer from the support is said to suppress platinum oxidation and speed up a rate-determining dehydrogenation step. The team also reports that iron-nitrogen sites promote water dissociation. This, in turn, helps convert nitrogen species that block platinum into reactive NH-containing intermediates, freeing blocked sites and restoring activity. These are the mechanisms described in the report; the supplied account does not provide further measurements with which to assess them independently.
The researchers paired the catalyst design with periodic reversal of the electrical current, occasional acid washing and replenishment of ammonia. According to the report, this combination helped restore catalyst activity and keep hydrogen production going. The difference between the two test durations—more than 2,000 hours at low current and 500 hours at a substantially higher current—shows why operating conditions matter when interpreting durability. The account does not give the current values or hydrogen production rates.
The research was carried out with Assistant Professor Ou Pengfei of NUS’s Department of Chemistry and Professor Fan Lei of the University of Electronic Science and Technology of China. The report says the findings were published in *Nature Synthesis*, with publication details listing Rui Jiang and colleagues. Jiang, identified as a research fellow in NUS’s Department of Chemistry, described the water-assisted regeneration approach as a way to keep nitrogen from blocking platinum for longer. Professor Chen suggested that the design principles might also apply to other ammonia oxidation uses, including direct ammonia fuel cells.
Longer catalyst life could make ammonia-based hydrogen production more practical, particularly if it can support production closer to where hydrogen is used. But the reported laboratory durations alone do not establish commercial readiness, overall energy efficiency or performance at larger scale. The account says further research is needed to evaluate the technology at larger scales.