Cu-doped CdZnS nanocrystals: a leap forward in selective photocatalytic CO2 reduction to methane†

Our research has demonstrated a significant correlation between the Cu doping concentration in CdZnS and its photocatalytic performance, with CZS-2 exhibiting a 15-fold increase in methane (CH₄) production rate compared to pristine CZS, reaching a peak value of 519.2 μL g⁻¹ h⁻¹. Moreover, CZS-2 demonstrates an unprecedented CH₄ selectivity of 85.3%, surpassing previously reported values for analogous systems. In-depth electrochemical analysis reveals that Cu doping strategically modifies the electronic structure of CZS-x, facilitating efficient charge separation and transfer. This optimization minimizes charge recombination, leading to the selective promotion of CO₂ reduction to CH₄.