Physical mixing of piezo-electrocatalysts and graphene oxide to promote CO2 conversion

Piezo-electrocatalytic CO2 reduction reaction (PECRR) technique has been verified as an effective CO2-to-fuel conversion strategy by exploiting and utilizing the widely distributed mechanical energy in nature, e.g., blue energy. The facile large-scale preparation of high-performance and low-cost piezo-electrocatalysts is therefore highly desired but challenging. Herein, a method of physical mixing of piezo-electrocatalysts and earth-abundant carbon-based materials is proposed to address the above issue, and we verified this method with typical piezoelectric BaTiO3 and graphene oxide (GO) as a demonstration. With an optimized GO concentration, the BaTiO3 shows a CO yield of 134.4 μmol g−1 h−1 which is about 45.3 % higher than that of pristine BaTiO3. The mechanisms for the enhancement are revealed via boosted piezo-carrier dynamics and charge transfer from BaTiO3 to GO as well as enhanced intrinsic activity. Furthermore, physical mixing of GO is extended to other piezo-electrocatalysts (MoS2, ZnO, ZnS, CdS, Bi2WO6), from which it is found that their performance is improved compared to the counterpart of those without GO. This work suggests that the physical mixing GO is a universal method to improve PECRR performance and may be a decent candidate approach for large-scale preparation of high-performance and low-cost piezo-electrocatalysts in future.