Executive Summary : | The conventional route of urea production involves energy and capital intensive two–step process. At first ammonia is produced by reacting nitrogen with hydrogen (N2 + H2 → NH3) by the Haber-Bosch process at high temperature and pressure (350–550°C, 150–350 bar), followed by the reaction of produced ammonia with carbon dioxide to form urea [NH3 + CO2 → CO(NH2)2] under mild reaction conditions (170–200°C and 200–250 bar). Overall, this two-step process for large scale production of urea consumes high energy and releases greenhouse gases to the environment. Therefore, electrochemical urea synthesis by the co-reduction of nitrogen sources (N2/NO2–/NO3–) and CO2 using efficient electrocatalyst in water medium under ambient conditions presents a sustainable and eco-friendlier alternate route. But, this single step electrochemical process has hit a roadblock due to the lack of efficient and economically viable electrocatalyst with dual active sites for co-reduction of N2/NO2–/NO3– and CO2 gas molecules. Therefore, the design and developement of electrocatalyst with higher urea yield rate and Faradaic efficeincy (FE) are key factors to resolve this problem. To increase the yield rate and FE, an in-depth understanding of the active sites, specificity and selectivity of electrocatalyst towards simultaneous reduction of gases and suppression of hydrogen evolution reaction (HER) are of utter necessity. In our previous report, metal phthalocyanine (MPc) nanostructures such as cobalt phthalocyanine (CoPc), nickel phthalocyanine (NiPc) have shown very optimistic electrochemical nitrogen reduction reaction (NRR) activity. Recent report also exhibited CuPc-carbon nanotube (CuPc-CNT) is an attractive electrocatalyst for CO2 into CO with high FE at low potential. Therefore, the availability of the multiple active sites (metal center, Pyrrolic-N3, Pyrrolic-N2, and Pyridinic-N1) in the MPc structure has the ability to co-reduce the dual gases (N2 and CO2). In this state-of-the-art, this proposed project aims to develop effective MPc based electrocatalysts having specificity and selectivity towards simultaneous reduction of N2/NO2–/NO3– and CO2 gases through the formation of C–N bond for urea under ambient conditions. Moreover, our recent study based on the proposed pristine CuPc nanotubes exhibited the promising urea yield rate and FE by co-reduction of N2 and CO2. In case of any heterogeneous catalysis, performances are limited due to their non-conducting or aggregating nature, leading to low reduction current density. Therefore, we foresee that surface functionalization of electrocatalyst or embedding on conductive carbon nanomaterials host will be instrumental in enhancing the reduction current densities towards the development of high performance electrocatalyst for N2/NO2–/NO3–and CO2 reduction to form urea. |