Herein, a split-type immunoassay strategy instigated by cation exchange (CE) and changing the capacity of an electron donor in an electrolyte solution is optimized, namely, for differentiating the biological-specific binding assay and photoelectrochemical (PEC) analysis. MoSe 2 /CdSe, a Z-scheme heterojunction with efficient visible light absorption and a low recombination of carriers, is used as a photoelectrode substrate. Silver ions (Ag + ) as the initiator of CE are generated by the acidolysis of evenly loaded silver nanoparticles on mesoporous silica nanospheres (MSNs). The theoretical calculation and experimental results confirm that Ag + replaces Cd 2+ in CdSe and retains the crystal structure of MoSe 2 . However, this behavior destroys the perfectly matched heterojunction structure and introduces defects, which led to the reduction of the photocurrent response. In addition, ascorbate oxidase in combination with MSNs can be used as a consumptive agent of the electron donor, which further improves the sensitivity and reliability of the sensor. As a proof of principle, neuronspecific enolase was applied to elucidate the potential application of the PEC immunoassay in clinical diagnosis, and the obtained linear range of the sensor was from 0.0001 to 100 ng/mL with a detection limit of 28 fg/mL (S/N = 3).

Bimolecular nucleophilic substitution (S N 2) reactions are of great importance in chemistry and biochemistry due to their capability of constructing functional groups. In this work, we investigate the solvent effect on the free energy profiles of symmetric and asymmetric S N 2 reactions in the acetonitrile solution using the proposed reaction density functional theory (RxDFT) method. This multiscale method utilizes quantum density functional theory for calculating intrinsic reaction free energy coupled with classical density functional theory for addressing solvation contribution. We find that the presence of acetonitrile brings both the polarization effect and solvation effect on the reaction pathways. For the eight selected symmetric S N 2 reactions, the predicated reaction pathways agree well with the results from the direct and thermodynamic cycle (TC) methods with the SMD-M062X solvation model. In addition, the polarization effect reduces the free energy barriers by about 6 kcal/mol, while the solvation effect increases the barriers by about 18 kcal/mol. For the four selected asymmetric S N 2 reactions, the predicted reaction pathways agree well with the results from the Monte Carlo simulations and experiments. The polarization effect and the solvation effect mutually reduce the free energy barriers, and the solvation effect plays a dominant role.

Decoration of noble metals with transition-metal oxides has been intensively studied for heterogeneous catalysis. However, controllable syntheses of metal−metal oxide heterostructures are difficult, and elucidation of such interfaces is still challenging. In this work, supported IrCo alloy nanoparticles are transformed into supported Ir−CoO x close-contact nanostructures by in situ calcination and following selective reduction. Relative to Ir/Al 2 O 3 , Ir−CoO x / Al 2 O 3 shows greatly enhanced activities for the hydrogenation of furfural derivatives to the corresponding furfuryl alcohol derivatives with more than 99% selectivity and demonstrates significantly improved activities and selectivity for hydrogenations of α,β-unsaturated aldehydes to α,β-unsaturated alcohols. The modification of Ir surfaces with CoO x prevents Ir nanoparticles from growing, achieving high thermal and catalytic stabilities. Theoretic calculation suggests that the better catalytic performance of Ir−CoO x /Al 2 O 3 is ascribed to the Ir−CoO x interaction, which promotes the absorption of furfural as well as desorption of furfuryl alcohol, resulting in enhanced catalytic activities.