The Preparation Of Mixed Metal Compound Catalyst Is Used In Electrocatalytic Synthesis Of Ammonia And Urea

Ammonia（NH₃）is an important chemical substance,an energy storage intermediate and a carbon-free energy carrier,and is closely related to the production and life of human society.NH₃ and its derivative urea have been relying on the traditional Haber-Bosch industrial synthesis method,but this process requires high temperature and high pressure conditions and the emission of a large amount of CO₂ aggravates the greenhouse effect.Therefore,it is very necessary to develop low-energy-consumption,green,and sustainable strategies for ammonia and urea synthesis.The electrochemical ammonia and urea technology using water as the proton source and renewable energy as the power can eliminate the drawbacks of fossil fuels as a source of hydrogen and energy,and at the same time greatly reduce carbon emissions in industrial production.It is expected to become an alternative process for industrial ammonia synthesis.In this paper,Pt-W/Mo@rGO and Bi-BiVO₄/FeOOH-X composite catalytic materials were synthesized using mixed metal multi-metal oxygen clusters H₃PW₆Mo₆O₄₀ and porous nanotubes FeOOH as precursors,which were used as electrocatalysts,respectively,to realize efficient electrocatalytic synthesis of ammonia and urea.1.Inspired by biological nitrogenase,a W/Mo polyoxometalate-derived catalyst was constructed for efficient electrocatalytic nitrogen reduction.Using Keggin polyacid H₃PW₆Mo₆O₄₀as a precursor,W/Mo doped electrocatalysts were prepared by high temperature calcination,and a trace amount of Pt was supported on the surface of W/Mo@rGO by in-situ electroplating to obtain Pt-W/Mo@rGO composite catalyst.Taking advantage of the multi-metal synergy in the catalyst Pt-W/Mo@rGO-6,the electrocatalytic ammonia synthesis experiment was carried out in 0.05 M H₂SO₄electrolyte,and the NH₃ yield reached 79.2μg h^-1 mg^-1_cat,and the FE was as high as20.0%.The results of continuous electrolysis for 24 h and 5 cycles showed that the catalyst had excellent catalytic activity and stability.2.Construct Bi-BiVO₄/FeOOH mixed metal composite catalytic material,and use electrocatalytic technology to synthesize high value-added chemical urea.Firstly,one-dimensional nanotube FeOOH was synthesized by polyacid etching,and it was mixed with ammonium metavanadate and bismuth nitrate.BiVO₄/FeOOH heterostructure was constructed by hydrothermal method,and then prepared by Na BH₄ reduction.A Bi-BiVO₄/FeOOH mixed metal composite catalyst was developed.In 0.1 M KNO₃ solution,the electrocatalytic synthesis of urea reached a yield of 9.7 mmol h^-1 g^-1 and FE of 13.0%,realizing an efficient electrocatalytic C-N coupling reaction under ambient conditions.