Photocatalytic H2O2 production is a sustainable and inexpensive process that requires water and gaseous O2 as raw materials and sunlight as the energy source. However, the slow kinetics of current photocatalysts limits its practical application. ZnO is commonly used as a photocatalytic material in the solar-to-chemical conversion, owing to its high electron mobility, nontoxicity, and relatively low cost. The adsorption capacity of H2O2 on the ZnO surface is low, which leads to the continuous production of H2O2. However, its photoresponse is limited to the ultraviolet (UV) region due to its wide bandgap (3.2 eV). Polydopamine (PDA) has emerged as an effective surface functionalization material in the field of photocatalysis due to its abundant functional groups. PDA can be strongly anchored onto the surface of a semiconducting photocatalyst through covalent and noncovalent bonds. The superior properties of PDA served as a motivation for this study. Herein, we prepare an inverse opal-structured porous PDA-modified ZnO (ZnO@PDA) photocatalyst by in situ self-polymerization of dopamine hydrochloride. The crystal structure, morphology, valency, stability, and energy band structure of photocatalysts are characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), electrochemical impedance spectroscopy (EIS), Mott-Schottky curve (MS), and electron paramagnetic resonance (EPR). The experimental results showed that electrons in PDA are transferred to ZnO upon contact, which results in an electric field at their interface in the direction from PDA to ZnO. The photoexcited electrons in the ZnO conduction bands flow into PDA, driven by the electric field and bent bands, and are recombined with the holes of the highest occupied molecular orbital of PDA, thereby exhibiting an S-scheme charge transfer. This unique S-scheme mechanism ensures effective electron/hole separation and preserves the strong redox ability of used photocarriers. In addition, the inverse opal structure of ZnO@PDA promotes light-harvesting due to the supposed "slow photon" effect, as well as Bragg diffraction and scattering. Moreover, the enhanced surface area provides a high adsorption capacity and increased active sites for photocatalytic reactions. Therefore, the resulting ZnO@PDA (0.03% (atomic fraction) PDA) exhibits the optimal H2O2 production performance (1011.4 μmol•L −1 •h −1 ), which is 4.4 and 8.9 times higher than pristine ZnO and PDA, respectively. The enhanced performance is ascribed to the improved light absorption, efficient charge separation, and strong redox capability of photocarriers in the S-scheme heterojunction. Therefore, this study provides a novel strategy for the design of inorganic/organic S-scheme heterojunctions for efficient photocatalytic H2O2 production.

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adsu.202200381.

Compared with other components, actuator fault has a higher probability of occurrence in semi-active suspension with magneto-rheological (MR) damper, which will lead to the safety and reliability of the system. Hence, the fault diagnosis and fault-tolerant methods of semi-active vehicle suspension system with MR damper are investigated in this paper to deal with the fault of MR damper. Firstly, the quarter-vehicle suspension system model is established. Secondly, an unknown input observer (UIO) with strong robustness and simple structure is employed to detect the fault of MR damper; meanwhile, the correlation coefficient method based on the system residuals is used to isolate the fault of MR damper. Lastly, the skyhook fault-tolerant controller (FTC) is designed to compensate the system with fault application. The simulation results under sine excitation, random excitation and bump excitation show that the performance of the proposed FTC always outweigh that of without fault-tolerant when MR damper occurs fault.

In the intelligent control system of magnetorheological (MR) suspension of all-terrain vehicle(ATV), the low-frequency disturbance(LFD) in the measured feedback signal (acceleration) makes the controller unable to calculate the theoretical control force accurately. Especially, when the frequency of the LFD signal is close to that of the actual acceleration signal, the LFD can’t be filtered by designing a traditional filter. Based on the above questions, this paper proposes an incremental proportion integration differentiation (IPID) strategy to address the issue of LFD in the measured feedback acceleration signal of the MR suspension system of ATV. First of all, the model of 1/4 vehicle suspension in consideration of LFD is established, the source of LFD is analyzed which is due to the transformation of Coriolis acceleration under the condition of vehicle body pitch and roll. Next, a semi-active IPID controller is designed by utilizing differential derivation of discrete PID and semi-active principle to eliminate the LFD component mixed in the acceleration signal by making a difference. The particle swarm optimization (PSO) algorithm is utilized to optimize the parameters of the controller, which is then verified through numerical simulation. Subsequently, a real vehicle control experiment is carried out based on a 4x4 ATV equipped with the MR suspension system and implemented by DSP controller with the designed IPID algorithm. The effectiveness of the prosed method is evaluated under the speed 10km/h and E road. And the designed method is compared with the traditional PID control algorithm through simulation and experimentation to demonstrate the superiority and rationality of "filtering out" LFD signal and improving control effectiveness.