Bond‐Competition‐Driven Enhancement of Surface Basicity and Interfacial Interaction to Boost Photocatalytic Syngas Production

The adsorption and photocatalytic conversion of CO 2 molecules to mitigate atmospheric greenhouse gas concentrations and manufacture value‐added chemicals require efficient CO 2 reduction reaction catalysts. In this study, a surface bond competition approach was developed to obtain high‐performance CO 2 adsorbents and syngas production photocatalysts via the sulfurization‐driven enhancement of surface basicity and interfacial interaction. The heat treatment of Mg–Al‐layered double hydroxide nanosheets under a flow of CS 2 yielded sulfur‐doped MgO/MgAl 2 O 4 S x nanosheets. The sulfur‐doping‐induced enhancement of surface basicity originated from the increased electron density on oxygen through competition with covalent metal–sulfur bonds, substantially enhancing the CO 2 adsorptivity. The sulfur‐doped MgO/MgAl 2 O 4 S x nanosheets acted as effective hybridization matrices for ZnIn 2 S 4 nanoplates, boosting their activity for photocatalytic syngas production (i.e., ≈3.3 mmol g −1 h −1 with the ratio of CO/H 2 = 2.2). Density functional theory calculations revealed that hybridization with MgO/MgAl 2 O 4 S x nanosheets was effective in lowering both the adsorption energy of CO 2 and the energy barrier for the conversion of *COOH to *CO. Systematic in situ spectroscopic investigations highlighted that the hybridization with MgO/MgAl 2 O 4 S x enhanced Lewis acid−base interaction between ZnIn 2 S 4 and absorbed CO 2 , and the contribution of associative pathways, which were attributed to sulfur‐doping‐assisted reinforcement in interfacial electronic coupling between hybridized components.