Polymolybdate-guided assembly of a thiacalix[4]arene-protected Ag nanocluster for electrocatalytic CO2 reduction.

A large polymolybdate-templated {Ag49Mo16} cluster protected by six thiacalix[4]arene (TC4A) molecules was synthesized by a one-pot solvothermal reaction. Structural analysis shows that the {Ag49Mo16} is assembled by inserting a [Mo6O22]8- cluster into a [Ag49Mo10@(TC4A)6] cage, representing the first polyoxometalate-templated Ag cluster protected by calixarene macrocyclic ligands. The solution stability and photoelectric properties of {Ag49Mo16} are discussed. Furthermore, this POM-templated Ag nanocluster realized electrocatalytic CO2 reduction applications, and 44.75% CO faradaic efficiency (FE) was obtained at a voltage of -0.8 V (vs. RHE).