Scientist develops new electrocatalytic method for producing ammonia

A scientist at the Institute of Nano Science and Technology (INST), Mohali, Punjab, has developed a electrocatalytic method of producing ammonia.

The traditional way of producing ammonia is by the age-old Haber-Bosch process, which calls for high temperature and pressure and emits lots of carbon dioxide. Electrochemical methods of producing ammonia are carbon-free, but they yield uneconomically low amount of ammonia, because the production of ammonia is accompanied by the release of hydrogen gas.

A team led by Dr. Ramendra Sundar Dey of INST has found a way around this problem. The process developed by the team supresses hydrogen production and hence gives out more ammonia. 

The new process is called interface engineering. It interfaces nanoporous gold (NPG) with Tin sulfide (SnS₂) and extensively investigated the alteration in the electronic band structure of the hydrogen evolution reaction (HER) with high Faradaic efficiency of 49.3 % for ammonia synthesis. This is, till date highest among all the SnS₂ based and interface engineering-based materials for NRR.

“Our research approach could pave path for the development of a catalyst, which would act well as an HER suppressant and is capable to compete with several high-performance catalysts to achieve a high Faradaic efficiency for NRR,” added Dr. Ramendra Sundar Dey.

For those who want to know more technical stuff about the process here is an extract from the government press release.

For any electrocatalytic process, the conductivity and d-band centre of the semiconductor could be improvised by interfacing the same with a metal.  

The synthesis of NPG@SnS₂ firstly involved cleaning of glass substrates successively with IPA, water, and acetone to do away with any kind of aerial impurity. This step was followed by the acid etching of the gold−silver alloy to obtain nanoporous gold (NPG), which was then transferred onto the glass substrates. This layer was coated with 100 nm thick Sn layer, which was then subjected to sulphurization in Ar atmosphere to obtain the semiconducting SnS₂ layer over NPG and a metal−semiconductor interface at their junction.

INST team believes that the progress represented in this work is of immense importance to fine-tune the electronic properties of a semiconducting material with a suitable metal-semiconductor heterojunction according to the demands of the electrocatalytic process. The interfacial engineering strategy of catalyst development adopted in this work could be potentially used to achieve high Faradaic efficiency for electrochemical nitrogen reduction reaction by suppressing its competitive counterpart, that is, hydrogen evolution reaction (HER).

The scientists are yet try for industrial-scale ammonia synthesis with this material. But if the Faradaic efficiency for ammonia synthesis is considered, then this material can be surely worked upon for industrial preparation of ammonia.