Zeolite templated carbon from Beta replica as metal-free electrocatalyst for CO2 reduction

Abstract

Zeolite Templated Carbons (ZTCs) are a class of materials that feature the textural properties of the template zeolites and the high conductivity of graphene-like structures. These characteristics make ZTCs a valuable candidate for CO2 catalytic reduction. We report here for the first time that metal-free ZTCs obtained from Beta zeolite are a novel valuable energy material for the reduction of CO2 to formic acid, about 10 times better than a reference reduced graphene oxide catalyst. In addition, it is evidenced that the pristine ZTC contains a large amount of oxygen, an aspect largely underestimated in literature. A specific method to reduce this oxygen content was developed, that coupled to an in-depth characterization by multiple techniques of these materials, allows to understand the nature of the oxygen functionalities on ZTCs surface. Moreover, it was evidenced that the change of oxygenated species by combined thermal and NaBH4 treatment of ZTCs affects the catalytic behavior, leading to a remarkable increase in the performances compared to the pristine one. The comparison of the performances and characteristics of two ZTCs, obtained by different BEA nanostructures, allow to correlate better the modification of the type of oxygen species present in ZTCs to the catalytic behavior. The results open new perspectives for the catalytic application of deoxygenated ZTCs.