Low Temperature Thermal and Solar Heating Carbon-Free Hydrogen Production from Ammonia Using Nickel Single Atom Catalysts

摘要

Catalytic splitting NH_3 to H_2 is one of the foundations for building a carbonfree H_2 energy system but requires NH_3 splitting catalysts that are highly active and durable at low temperatures. Although various non-noble catalysts have been designed, NH_3 splitting still operates at relatively high temperatures (600–850 ℃). Herein, theoretical calculations predict that the Ni single atoms can change the bonding mode of Ni-N from covalent bond to ionic bond to boost the NH_3 splitting activity. Further, Ni single atoms supported on CeO_2 nanosheets (SA Ni/CeO_2) are synthesized by the sol–gel method, which exhibits a robust 3.544 mmol g~(?1) min~(?1) of H_2 yield speed of NH_3 splitting at 300 ℃, superior to all non-noble catalysts and most of the noble catalysts. Combing with the homemade solar heating device, the one sun-driven NH_3 splitting over SA Ni/CeO_2 shows a stable H_2 yield of 1.58 mmol g~(?1) min~(?1), 100 times the record value of advanced weak solarpowered NH_3 splitting, demonstrating the potential for practical application in carbon-free H_2 systems.