Cu 2 O/SnO 2 Heterostructures: Role of the Synthesis Procedure on PEC CO 2 Conversion.

Addressing the urgent need to mitigate increasing levels of CO 2 in the atmosphere and combat global warming, the development of earth-abundant catalysts for selective photo-electrochemical CO 2 conversion is a central and pressing challenge. Toward this purpose, two synthetic strategies for obtaining a Cu 2 O-SnO 2 catalyst, namely co-precipitation and core-shell methods, were compared. The morphology and band gap energy of the synthesized materials were strongly different. The photoactivity of the core-shell catalyst was improved by 30% compared to the co-precipitation one, while its selectivity was shifted towards C 1 products such as CO and formate. The stability of both catalysts was revealed by an easy and fast EIS analysis, indicating how the effective presence of a SnO 2 shell could prevent the modification of the crystalline phase of the catalyst during PEC tests. Finally, directing the selectivity depending on the synthesis method used to produce the final Cu 2 O-SnO 2 catalyst could possibly be implemented in syngas and formate transformation processes, such as hydroformylation or the Fischer-Tropsch process.