Selective photocatalytic CO2 reduction (PCR) to CH4 remains challenging due to the sluggish charge transfer kinetics and the involved complicated C1 intermediates. Herein, the deliberately engineering Lewis acid-base interfaces in Cu2S/ZnIn2S4 hollow hetero-nanocages (HHNCs) were constructed, and the enhanced PCR activity and selectivity has been achieved due to accelerated electron transfer and stabilized intermediates. Both experimental and theoretical results have demonstrated the construction of a Lewis base interface with Cu2S and a Lewis acid interface with ZnIn2S4, which exhibit strong CO2 adsorption and reduction of the Gibbs free energy in the hydrogenation step (*CO to *CHO). As a consequence, a CH4 yield of 23.3 µmol g−1 h−1 under visible light irradiation (λ > 400 nm) has been obtained with the Cu2S/ZnIn2S4 HHNCs, approximately 13.7, 10.1 and 6.3 times higher than that of bare Cu2S, ZnIn2S4 and physically mixed sample (Cu2S/ZnIn2S4-mix), respectively. The product selectivity of CH4 is as high as 93.2%, in sharp contrast with 59.5% for Cu2S/ZnIn2S4-mix, 53.1% for Cu2S and 35.4% for ZnIn2S4. This work demonstrates an rational strategy to engineer heterogenous Lewis acid-base interfaces for improving PCR activity and selectivity.
