Probing the role of surface speciation of tin oxide and tin catalysts on CO2 electroreduction combining in situ Raman spectroscopy and reactivity investigations

Electrochemical CO2 reduction to formate is a promising approach store renewable electricity and utilize CO2. Tin oxide catalysts are efficient for this process, while the mechanisms underneath, especially existence role of oxidized tin species under electroreduction conditions remain unclear. In work, we provide strong evidence on presence both SnO2 Sn during via in situ surface-enhanced Raman spectroscopy, different nature. Reactivity measurements show similar activity selectivity production catalysts. Combined analysis spectra reactivity results suggests that Sn(IV) Sn(II) unlikely catalytic formate.