In2O3 uniformly modified MoS2 (In2O3/MoS2) nanoflowers were synthesized via a green, efficient, and controllable normal-pressure microwave-assisted route and a subsequent calcination process, using MoS2 nanoflowers as substrates. The In2O3/MoS2 nanoflower is composed of extremely thin MoS2 nanosheets, among which In2O3 nanoparticles are uniformly attached to the MoS2 nanosheets. Numerous p–n heterojunctions and oxygen vacancies are present on the surfaces of the In2O3/MoS2 nanoflowers. The In2O3/MoS2 composites exhibited high sensitivity and selectivity, along with rapid response and recovery to methanol vapor at 240 °C. The In2O3/MoS2 nanoflower sensors exhibit rapid response and recovery rates toward methanol, particularly notable with a recovery time of only 15 s for 100 ppm methanol. The In2O3/MoS2 sensors also demonstrate excellent stability and reproducibility, with a remarkable selectivity toward methanol. This research presents a promising approach for the future design and preparation of In2O3/MoS2 composite for methanol detection.

While graphene-based lubricants are well-studied, the tribological potential of emerging carbon–nitride and carbon–boron 2D materials remains largely unexplored. Herein, by using first-principles calculations implemented in the VASP code, we systematically explored the interlayer interactions and frictional properties of bilayer homojunctions and heterostructures composed of graphene, C₃N, and C₃B. The DFT-D3 dispersion correction was employed to accurately capture the interlayer van der Waals forces. The results reveal that C₃N/C₃N, C₃N/graphene (C₃N/Gra), and C₃B/graphene (C₃B/Gra) systems exhibit significantly lower friction coefficients compared to pristine bilayer graphene (Gra/Gra). Notably, the sliding potential barrier of the C₃N/Gra heterostructure is only ~0.45 meV/atom (approximately 1/10 that of the Gra/Gra system), manifesting exceptional superlubricity and considerable potential for superlubricant applications. The sliding potential barrier of the C₃B/C₃N heterostructure is slightly smaller than that of Gra/Gra. In contrast, the C₃B/C₃B homojunction exhibits high resistance to sliding; under normal loads of 1–4 nN, its potential barrier ranges from ~16 to ~115 meV/atom, which is consistently twice that of Gra/Gra. The observed frictional variations are attributed to sliding-induced interfacial charge redistribution. These findings provide fundamental insights into the tribological behavior of C₃N- and C₃B-based materials and establish a quantitative link between frictional properties and interfacial charge dynamics, offering a theoretical basis for the development of advanced graphene-derived lubricants.