Achieving high cyclohexanone selectivity via La³⁺-Doped MoO3-x /Carbon dot s-scheme photocatalyst

Overcoming the limitations of high energy consumption and over-oxidation in cyclohexanol-to-cyclohexanone conversion requires efficient photocatalytic strategies. This work presents a dual-engineered MoO_3-x catalyst, modified through La³⁺ doping and coupled with electron-enriched carbon dots (CDs) to form an S-scheme heterojunction (LMOCDs). La³⁺ doping induces lattice distortion and oxygen vacancies, enhancing carrier mobility, while the S-scheme junction with CDs significantly boosts charge separation and enables directional interfacial electron transfer. Under ambient conditions, the optimized LMOCDs catalyst achieves exceptional cyclohexanone selectivity of 97.7 % and a conversion efficiency of 19.1 %, representing a 1.93-fold enhancement over pristine MoO_3-x. The synergistic effects of La³⁺ doping and CDs compounding not only promote the selective adsorption of cyclohexanol but also dramatically improve the utilization of photogenerated charge carriers. Photoelectrochemical characterization, band alignment analysis, and radical trapping experiments elucidate the underlying mechanism. This study demonstrates the pivotal role of combined cation doping and S-scheme heterojunction engineering in developing high-performance photocatalytic systems for selective oxidation.