A strong Jahn-Teller distortion in Mn3O4-MnO heterointerfaces for enhanced silver catalyzed formaldehyde reforming into hydrogen

The Jahn-Teller effect has received intense interest in the field of catalysis because of its ability to optimize the surface electron state to tune the adsorption behavior of reactants on catalysts. Herein, direct evidence of a strong Jahn-Teller distortion at Mn3O4-MnO heterointerfaces is reported, which is used to regulate the electronic and lattice structures of the Mn3O4-MnO composite support and effectively enhance the activity of Ag nanoparticle-catalyzed H-2 production from formaldehyde. Benefiting from the improved density and properties of adsorption sites in Mn3O4-MnO by the stabilization of Mn3+ at the heterointerface, the lattice distortion affords abundant active sites for reaction intermediate conversion. Therefore, Ag/Mn3O4-MnO exhibits the highest catalytic efficiency for formaldehyde reforming into H-2 at room temperature, which is one order of magnitude higher than that of its counterpart catalysts, such as Ag/Mn3O4, Ag/MnO and Ag/Mn3O4#MnO. Experimental observations and theoretical calculations indicate that the excellent performance can be attributed to the distorted heterointerface, where the Ag NPs and the weak Mn-O bond caused by the strong Jahn-Teller effect are responsible for C-H bond cleavage and O-H activation, respectively. The stabilization of Mn3+ at Ag/Mn3O4-MnO heterojunction interfaces results in local electron accumulation and a modulated d electron state, facilitating the adsorption of hydrogen-involving intermediates. This work provides new insights into the Jahn-Teller distortion in catalyst engineering to bring about further practical benefits to chemical processes involving sustainable energy conversion.

Automated summary

This study reports a strong Jahn-Teller distortion at Mn3O4-MnO heterointerfaces, which can regulate the electronic and lattice structures of the composite support, enhancing the catalytic activity of hydrogen production from formaldehyde.