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

ABSTRACT

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.